| Author | Message | ||
| truthunter
Rating: N/A |
I have been contemplating the addition of a 3 or 5 hp electric motor with 2nd compressor clutch above the factory air conditioning compressor to allow the factory A/C to run on shore power or generator when parked. I would run factory 24 VDC evaporator & condensor blowers and controls with "house battrey charge system" when not driving. Can I get some constructive critism on such a novel headace. | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
Depending on which compressor u have on your bus, usually a Carrier 05, your dealing with a 20-25 hp compressor back there. Even fully unloaded, your looking at approx 10-12 hp to drive it. Beyond just turning the compressor, there are many other considerations to making the bus system work effectively. Bottom line, 3-5 hp won't do it. It would be marginal at best on something as small as Honda CRV. | ||
| Ed Jewett (Kristinsgrandpa)
Rating: N/A |
Have you tried a keyword search? This comes up a couple of times a year. I thought it would be a good idea till I read the pro's amd con's. One of the things is the cost to replace/repair factory units, the fact that they are immensely oversized for conversion use, and a lot of extra weight compared to roof/basement/mini split units. I'm sure there are more knowledgable people that will post, but the general consensus is that it is generally better to go another route. I saw a similar set-up at bussin 2005 that apparently worked quite well. The man always had a crowd around looking at it. HTH Ed | ||
| TWO DOGS Rating: N/A |
I seriously thought about doing the same thing & everybody said it wouldn't work....I was thinking about a 5 h.p. high r.p.m (3400)elec. motor geared down (more power).. | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
Before you do much more thinking, investigate the full load running current and the locked rotor starting current required at 120 volts for a 5 hp single phase motor. IIRC the FLA is around 60 and LRA is 5-8 times that. Would need at least 100 amp main breaker I believe. And the 5 hp motor would probably not run the compressor with all the valves open. Richard | ||
| twodogst Rating: N/A |
240 volts | ||
| gillig-dan Rating: N/A |
I would also like to know why this wouldn't work with the right compressor/motor combo. It seems just two horsepower would produce about 20K btu's. That would be about 17 amps @ 110VAC. I don't know what the efficiency is of most automotive compressors but I sure would hope I'm not losing that much power. I am guessing, based on the window units I had in the bus, that 20K btu's would drop the interior about 15 degrees or more from the outside temperature, sitting in the sun. I'm going to be experimenting with this soon and let you know the outcome. I planned to use a belt tensioner system to switch between the engine belt and electric motor belt. I would be nice to modify the clutch with a second pulley coupled straight to the compressor shaft so, when it's running on electric, I wouldn't need to waste power on the clutch. Another consideration is that the heat load is less when parked then when I drive because the windows get covered when parked. I think the system will work if I can pull about 30K btu's driving and 20K btu's parked. I'd like to hear from anyone who is running an automotive compressor with an electric motor. I have a York model 210, 10 cu. inch compressor ready for the job. I haven't picked up a motor yet. I plan to run this through a 30,000 btu Carrier condensor and two evaporators. Finally, I am hoping to push the air across the main evaporator housed in a plenum with the fan from my propane furnace; just like the central air in my house. I tried to search the archives on this and haven't found very much reliable information. Gillig-Dan | ||
| truthhunter@shaw.ca
Rating: N/A |
Not sure but I think 100 amp breaker main might be a little overkill. I manage to operate my 5 hp(220 volt)air compressor in the shop without setting of the 20 amp breaker. Just like the A/C compressor in the bus (older style not the newer 05G) it has a unloader system and the compressor starts with no load on the pistons. Of course generated power is not the same as being hooked up on the utility line; when it comes to start-up. Thanks for the thought though. I am not sure about the 10 -12 hp requirements to run the A/C compressor. The best I could find at carrier web site was a rating of 5 hp for this compressor (forgot the model number already). Which could be lower if you reduce speed (via pulley size) and of course cooling output. Do correct me if anyone knows the proper power requirements on the MC 8 A/C compressor Ed did you happen to notice what size electric motor was used in the bus at Bussin 2005. Would relish (not mustard) to hear more about what you observed in that factory modification. | ||
| TWO DOGS Rating: N/A |
we have argued abut this for years...but...gas/desel power loss doesn't have any comparison to elec. horsepower...if you lose 20 h.p. when you turn on your air cond. IT DOES NOT MEAN YOU HAVE TO HAVE A 20 H.P. ELEC. MOTOR kinda the same thing on painting a car....I can paint with a 5 h.p. elec. compressor ...BUT...if it is a gas/diesel compressor ...I need a 10 h.p. | ||
| gillig-dan Rating: N/A |
So, if I can get a 20,000 btu roof unit to run on 110VAC at less than 20 Amps, how come I can't run an 20,000 btu automotive compressor with an electric motor on 110VAC? It seems to me, if you run the auto compressor at it's best output RPM, the systems should produce similar power. If an auto compressor is so much less efficient, wouldn't they be working on a better design? I do realize that temperature control on automotive units actually mix heater core air with the output to regulate temperature (how's that for efficient?, not, but still...). The average automobile system generates at least 20,000 btu's, even a for a compact car. Realize, a car sitting in the mall parking lot can get up to 150 deg F in no time at all. When you get in the car, you want it back to 75 degrees before you finish putting your wife's packages in the trunk. Still not convinced I should not to give it a try, Gillig-Dan | ||
| TWO DOGS Rating: N/A |
are you talking about a bus ??...my bus air is 9 tons.....20,000 btu will not cool a bus..that's only 1 1/2 tons | ||
| truthhunter@shaw.ca
Rating: N/A |
For years and still not resolved, boy I am in the right place ! An Irishmans paradise. Got my brain warmed up and remembered that the compressor is a Carrier 5F 30, the specs say 5 - 15 hp requirements (30 cid 3 cyl) could not remember the torque reqirements and could not refind them, but they were at low volume. Minimum speed 600 rpm and max 1750 rpm (may account for the horspower range of 5-15hp along with ambient tempature). This assums R-12 which is lower operating pressure than 134A at same ambient tempatures. The spec sheet is on pdf at http://www.xpedio.carrier.com/idc/groups/public/documents/techlit/5f,h-3pd.pdf if anyone would like to join my headach and try translate the specs. into layman. I am not a HVAC engineer yet, I will have to sleep overnight in a Holiday Inn first before I can make a educated guess before I try the practical application, some day not very soon (the tempature up here has been -40 lately). Have not been able to find anything in the BNO archives on past discussions; is there a way to do a quick search. Dog Dog you are correct about your rule of thumb on the comparison of typical combustion engine versus electric you have to include the torque to do a real comparison. It was normally said that electric motors are double the useful work of the same h.p. gas engine. Of course now days manufactrures do "cheat" on there electic motor ratings with low torque and high hp. I usely make a guess on a electrics useful work by comparing the amps with the hp before getting out the magnifying glass to look at the fine print on the lable. I was thinking of using a 5 hp (4 pole)1750 rpm motor and then "gearing/pulleying down the speed" of the A/C compressor to 700 rpm. These 1750 rpm motors have much more torque, are well sealed, higher heat rated for use in the engine compartment and are not much more expensive than a 3600 rpm compressor motor.(usally advertised as farm or industrial duty). | ||
| TWO DOGS Rating: N/A |
I would get the 3400 rpm...gearbox it down to 1000 rpm...a 3to1 reduction...would REALY boost your power...I'd use the clutch on the a/c unit, | ||
| John that newguy Rating: N/A |
The OE compressor is as large as it is, due to enormous amount of piping and gas needed to be as effective as it is. Trying to compress that much a volume of gas with a smaller compressor, is like trying to move that bus up Pike's Peak using a lawnmower engine. Before you knock yourself and your wallet out, look into the Welch auxiliary AC systems. You'd may be better able to do what you're looking to do with one of those. http://www.welchindustries.com/convkits.html | ||
| TWO DOGS Rating: N/A |
I hope he is not talking about a smaller compressor...I was talking about the bus a/c compressor.... | ||
| John that newguy Rating: N/A |
I misunderstood... But running the OE compressor slower will result in the same inefficient amount of compression. It's a helluva big system with a helluva lot of freon. It's all got to be moved throughout those lines quickly, if it's going to do it's job as designed (or at all?). | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
For those of you wishing to re-engineer the wheel, consider the following 2 facts: 1hp/hr=2545.6btu 1hp=746watts Both of these facts are based on 100% efficiency, which you ain't going to accomplish, regardless of how much engineering you do. To add to JTNG anology, this 3-5hp motor idea is sort of like a fart in a whirlwind or pissin' on the beach in Santa Monica trying to change the tide in Hawaii. | ||
| truthhunter@shaw.ca
Rating: N/A |
while the formual 1 hp/equals 2545.6 btu or 746 watts may be correct; that is not accurate that you can will get 2545.6 btu of in a Air Conditioning system per hp of compressor power. But thanks for your contribution , every fart helps. Your formula is only part of the equation. Do you want me to see if they have an extra room at the holiday inn for you, I can see I am not the only one who has not become a HVAC engineer. | ||
| John that newguy Rating: N/A |
"Doing it our way" has always been a great motto for bus converters, but trying to do the impossible isn't quite the same thing.... Try turning that OE compressor by hand; there's a reason they engineered it to have two belts driven off the crank pulley... Even if you can get a small 5hp motor to turn it, it'll never turn fast enough to amount to any serious compression of all that gas.. When you think seriously about it... Wouldn't the manufacturer have one helluva selling feature, to allow a bus company to keep their buses cool when in the depot without having to run the engine? Oh well, ehh? | ||
| Buswarrior (Buswarrior)
Rating: N/A |
Hello truthunter. You have my support to continue investigating a shore power solution to using the stock coach air parts. A lot of folks may not want you to succeed, they'll feel foolish for giving away or throwing out their HVAC equipment! Perhaps I might offer a little correction to what has already been offered? The 25HP figure attributed to the coach AC is a SWAG, popularly considered the total engine power needed to run the whole AC, the compressor and then the load on the alternator to run the coach blowers, the defroster(driver's AC) and condenser fans, all together counting up to beyond 2 1/2 HP of electric motors, that'll be worth quite a bit of load right there, generating all that electricity. oh, SWAG means: Scientific Wild A-- Guess. To put it in perspective, if you are climbing the big mountain, turning off the AC makes no driver discernable difference in performance; it still climbs poorly! Easy to do a test: pull the belts off the engine pulley and rig up another drive source for the AC compressor in the driveway and see if it will power the compressor while the coach takes care of the electrical. At least you'll find out if you can spin that thing under load? Come on folks, how about a little support for a guy trying to pioneer something the rest of us haven't??? happy coaching! buswarrior | ||
| truthhunter@shaw.ca
Rating: N/A |
Sorry John but I do not see your analogies leading directly to mechanical & engineering facts. If we were after mechanical beliefs we could guess that they use 2 belts for longlivity at full output (I was not looking for full output out of a 5 hp,just 50% output at most, like a 2 speed house AC). Without deeply contemplating manufacture design logic I would not think that most depo parked coaches need a 3-way-AC system- as they are rarely in the depo for more than 1 hour loading time; most of the time that they are occupied they are rolling; which is the opposite of a conversions primary mode for the application whcih I hope we can resolve together! Even though belief is not a complete subsitute for facts, at least we are contemplating the issue at hand, sort of some of the time. Which is my way of saying more farts and along with any available facts or observations please? The manufacture lives in a differnt box than us ("think outside the box") | ||
| Buswarrior (Buswarrior)
Rating: N/A |
Hey folks Go easy... I still haven't seen anything concrete that proves truthunter will not be able to get his coach AC to run off shore power. As long as he isn't endangering himself, perhaps if we have nothing nice to say, we might be best to keep quiet? happy coaching! buswarrior | ||
| truthhunter@shaw.ca
Rating: N/A |
Thanks for the encouragement BusWarrior. I would like to see no more Factory A/C removed and thrown out too. Please do not be to hard on the other's for there contributions, I did ask for both kinds of critic analyasis. It may prove to be rather efficent if all those resentments and regrets formed by "Post Tramatic Premature Factory Air Conditioning Removal Syndrome" can be healed in the course of our technical inquirey in this forum not to mention the posible prevention of any future cases. Hell I feel like I earned my days bread if I can help someone else fart. From my own personal experience keeping all that gas in puts too much presure on the mind and styfels the problem resolution process. I welcome all input too this swell think tank. Just hoping Fast Fred would feel fit to sew into this thread, hia insites are kind of like looking in a mirror. ARe you out there Fred? | ||
| Tom Caffrey (Pvcces)
Rating: N/A |
For the purposes of this thread, I seem to recall that the electric motors on submarines stay connected to the shaft while under diesel power. When running submerged, the diesels are not connected to the shaft. Diesel electric systems are another breed of cat; I was only thinking about the older equipment that used a clutch to tie diesel and shaft together. If you were driving a compressor through a clutch off of the PTO, the electric motor would not necessarily need to be unhooked from the compressor; it would only need to be turned off. IF the electric motor could start the compressor while the clutch on the PTO was disengaged, then the shifting equipment will only require switches and relays. I agree with Buswarrior in that I think the power used by air handling equipment is a big percentage of the total. Then, there's the power loss in the alternator. It all adds up. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| airless in Mississippi (Airless_in_mississippi)
Rating: N/A |
I really hope you can make this work.. I am behind you 100% in the attempt. For those doubting thomas's out there your great minds would still believe the world is flat. | ||
| TWO DOGS Rating: N/A |
go truth guy !!! get a grainger book & look for gearboxes & elec. (220) 5 h.p. motors..I would suggest a different hook-up....maybe a lovjoy coupling...instead of belts | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
Truthhunter & BusWarrior: Just so u will know, I have lived very comfortably for the past 31 yrs. in retirement from the proceeds of a relatively short career as a Industrial and Commercial HVAC Tech. I don't need a room in the Holiday Inn Express since I'm the guy that made the air work at The Westin and Hilton and am always welcome at several of them. I also did not scrap the central system of either of my 2 buses, although one of them currently has a scrambled compressor (12 ton Thermal King T-4--a scaled down knock-off copy of the old Trane TR-100). The other, and operating, is a 05G, which depending on a lot of factors, is capable of consuming 40 hp just for the compressor. Don't take my word(SWAG), find yourself a Carrier Spec. manual and read the entire thing. Just keep in mind, it takes 4.17 hp of energy to produce 1 ton of a/c at 100% efficiency, and I don't really care where u get that energy. Have fun adjusting the superheat on that 12 ton design evaporator trying to use it at 1-2 ton continuously! | ||
| Randall Hays (Bulldogie)
Rating: N/A |
When I had my 60 steel fishing boat I put in a reefer from a 18 wheeler into the fish hold (was tired of buying ice) ran it with a compresser with a 5 hp elect motor with 3 belt pullys. Also had it hooked up with another compressor to the Starbord 6-71 DD Could freeze a 55 galon barrel of salt water in about 12 hours. Had 8 of those in the hold. Talk to a good boat or truck reefer man about how to do it, that's what I did and put it all in my self with him only coming to solder the fittings and then we flushed it and he filled it then we tested it and off we went fishing never had any problems with the system. Ran the 5 HP off the 3-71 DD runing a 30kw power plant, I know over kill but that was what was in the boat when I bought it. You just have to size the pullys right and the reefer man will know what to tell you to do | ||
| truthhunter@shaw.ca
Rating: N/A |
Good thought Sunchaser but I am not sure that it would be good to leave the electic motor hooked in my proposed configaration as it is "pulleyed" or geared down to turn the A/C at less than half factory normal speed. If it was left conected with coach rolling this would overspeed the electic motor and harm the windings plus a lot of extra wear on the bearings and bushing. I was thinking of adding a 2nd electric clutch on the compressor to engage/disengage the electic drive, simialar to how the compressor can be engaged/disengage from the coach engine on the 0G5 system. The second clutch could be smaller and cheaper than the HD 1st factory (A/C to diesel engine) electic clutch as it is only 5 hp. Of corse one could just "simply" remove the belt for rolling mode in a economy prototype. This simple belt removal technigue could also be use on the older coach engine (my old MC 8 has the 5F 30 A/C without any electric clutch). Could always add the electric clutches (and accompanying modifications for controlling the clutches automaticlly and idot-proofed) at a later phase of developement. I agree with the condensor, evaporator and defroster power consumtion requirements do exceed 2 1/2 hp. It might be best to run these motors at a reduce speed (by reducing the voltagefrom 24 vdc to 12 vdc) as A/C compressor (and the cooling capacity ) are runnig at reduced speed. This will help conserve motor life, noise and lessen the draw on the house battery charging system (converor). It seems that 12vdc house battery systems are more common so this should be simple to configure. I have not put in my house battery system yet. | ||
| truthhunter@shaw.ca
Rating: N/A |
So then James you all ready spent the night at the holiday inn, that is a good thing. Hope you might decide to remmember more of what you allready know. Thanks for coming out of the closet on your skills, that is what I seek, more technical details or faster roads to them. The truth is always in the details. Actually Truth Hunter was an incredable dog friend that had made a positive influenced on me (she had emotional intelligence beyound any being I have yet to meet). I just copied her name in my email address to honour that memory. I can hardly claim the title of a truth guy. (Seeing how we are shareing backgrounds). Back to the design then, perhaps a one way clutch could be used to disconect the electric drive. They are cheaper than electric clutches but it would need a good seal. | ||
| FAST FRED Rating: N/A |
One problem you have overlooked is the compressor is VERY noisy when it runs. While that's not a problem with a DD running , you may leap out of bed every time it operates at night , as may your neighbors. On boats one fellow owned a patent (Adler Barbour) for eutetic (brine plates) with 2 freon circuits. One for the York spun by the engine , the other for a small Tecumsa can to cool at dockside. The competition decided that a belting arangement could be done ,to cool with only one freon circuit at dockside and built it. They were overwhelmed with complaints from the noise at night , so merly put it on a timer , so the fridge would only run while folks were awake , or better, gone. With only a tiny auto York the noise was loud , I can only imagine an old Carrier 3 cyl banging away with a 100 lb motor turning it. Reinventing the wheel sometimes has unexpected hassles, FAST FRED | ||
| gillig-dan Rating: N/A |
If the math formulas above are correct, how is it that AC manufactures can make a roof air that uses less than 1 amp per 1000 btu's? I can see how a factory bus air may not be efficient because you would be running it a long way from it's designed speed. But, in my case, I have a split system from a small transit van. Going down the road, running off the engine, I should get about 30,000 btu's. When parked, I figure I should get close to 20,000 btu's before I trip a 20 Amp breaker. I know factory bus systems are larger than this but I'm not trying to cool off 60 passengers looking at the view through 30 uncovered windows. I will be using a 10 cubic inch compressor. The system will have two evaporators. The main one, will be used when parked. The furnace fan will distribute the air, just like my home's central air. The second one, for dash air, will be valved in when the bus is rolling. An added option would be to use a left-over electronic variable speed controller I have so that the motor would automatically slow down if I start to pull too many amps. What am I missing here??? Gillig-Dan 35' Gillig 636 | ||
| T. (Bluegrass)
Rating: N/A |
Two Dogs Granger Catalog Is now online http://www.grainger.com/Grainger/wwg/start.shtml Tony | ||
| John that newguy Rating: N/A |
Truthhunter- Re: "If we were after mechanical beliefs we could guess that they use 2 belts for longlivity at full output (I was not looking for full output out of a 5 hp,just 50% output at most, like a 2 speed house AC). " I kept my OE AC system for use while the engine's running, and to cool the bus quickly after having sat in the southern sun unattended. The most power consuming part of cooling, is the time and power it take to cool the structure down initially. Once cooled, the cool temperature is easier to maintain, since -all- items in the structure are cooled to the same temperature. In the hot climates, the inside of a bus at a depot heats up very quickly while it sits with no air conditioning. Although the bus can sit for an hour or more, the engine cannot be running in port that long due to most all federal and local environmental legislation. Passengers would complain loudly if they had to board a very hot bus and sit in that heat while waiting for the remaining passengers and luggage to be loaded. The bus OE ac unit can cool the bus quickly and maintain that coolness at full power, but it would take forever to cool the bus if it ran at 1/2 power. If a manufacturer had a way to run it on "shorepower", it most definitely would be an offered option. People are a great source of heat. The bus is not insulated like some commercial freezer. The bus has windows, and a door that's open often and often left open. That makes a big difference, if someone is trying to compare the power needed to freeze food in a box insulated and designed to freeze food, versus the power cool a bus with a few hundred square feet of glass and fifty 98.6 degree heated bodies stuffed into it. Oh yes.... and a large heat producing engine under the rear seat. I asked your question some time back because I too, wanted to keep, and use, the bus air conditioning unit while at a campground, using the campground supplied power. While it may sound possible to do so, it is in fact, near impossible to do so. You would be very hard pressed to find any 110v motor large enough to provide the horsepower needed to be practical. If you cannot generate enough electricity using less than a 5kw genset to operate two conventional rooftop air conditioners, how would it be expected to run an air conditioner fifty times that size, on less power? Does anyone really expect a 5hp electric motor to be able to provide power to run a 10 ton compressor? Why in the world would home air conditioning manufacturers design such large units requiring such large and expensive 220v electric motors, if they could possibly produce as much cold air with a 5hp 110v motor? (The bus AC unit is twice as large) Why would they need a separate 220v supply using maximum amps, if they could do it with 110v and 15 amps? If you do manage a way to accomplish this feat, please post your results ASAP. Don't give away the plans and blueprints, however.... -They- would be worth millions! | ||
| John that newguy Rating: N/A |
Dan- The question was regarding the use of the bus original equipment air conditioning system and powering it with a 5hp electric motor for use at a campground. Smaller, split systems are an entirely different animal. | ||
| gillig-dan Rating: N/A |
I'm just trying to ride on Truth's coattails on this one. I asked a similar question a while back. Never really got a satisfactory answer. I agree with the general consensus around here that the full size bus AC is overkill for a RV. This would cause short cycling and be very inefficient moving and parked. I got my systems evaporator and condenser from a fellow busnut on this board and I'm very optimistic it will work well for me. The compressor was a $20.00 ebay score for an unused York 210. Generally, trips are planned so that we are heading for better weather when traveling. North in the summer, south in the winter. So, what's the minimum BTU's Busnuts install?? I doubt I'll ever head to south Texas in July. Gillig-Dan 35' Gillig 636 | ||
| truthhunter@shaw.ca
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Arr yes worth millions it mgiht be too the one with marketing desires and infastrucre; tiss better to have invented and been patent jumped than to have puckered up and never created at all. Just like love,I figures! Tis the ultamite doom of all collective creative efforts and yet the motive of the sport of competetion. The good thing here is we are all bothering to put on our thinking caps without reserve. Insperation should remain free, just like air (fart free air anyhow). If we are going to look at the notion of running the system at reduced output in the context of EFFRICENCY LOSS (without benifit of qualified HVAC engineer)- does anyone have experience with the two stage central house A/C (like the Tempstar model sitting out my backdoor)or the comercial units for refridgeration that employ two stage or multi stage. I can see a slight efficency loss will occur in pumping 35 feet to the condensor, but I can not see how it would be a massive loss. And perhaps itwas not designed as efficent as a roof-top to begin with, but I doubt the efficency of roof tops or house central A/C is that much better than bus manufactors. There is never a free engineer when you need one! I was thinking of 220 volt motor not 110 in my idea. My understanding is 220 motors are used in industry more for econmomics/compactness than the slight reduction in line loss that results from using 220 volts. Of course some parts of this planet do not use 110 volt for anything! Using laymans guess-ta-mite calculations, if two 15,ooo btu roof top A/C (using about 14 amps/110 volts each) can maintain the motorhome conversion comfort (lets not try to solve passenger haul with this modification, not right now, stay focused), then if the factory setup can be operated at less than full capcity (with a variable orfice or "superheat") and produce the same 30,000 btu rather than it's full potential of 250,000 btu, should this not do the same work as the two rooftops? Yes there is a little more inefficency in the frictional loss of a oversized compressor but that too is small as the oversized compressor is run at slower rpm. One question for those that are seasoned with the RV parks- I understand that many offer 50 amp service and the rest offer 30 amp. What I do not know (no experience) are these hook-ups 110 volt sevice or 110/220 volt service just like a house 100 or 200 amp service? The noise consideration is a good point and may require address if this makes it to those latter stages of deveopement. There are ways to deal with that and they do add complexity and cost. | ||
| Buswarrior (Buswarrior)
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hello truthunter The stock compressor doesn't run all the cylinders all the time.... A small circuit for messing with the stock solenoid controls, and voila, 1/3rd, 2/3rd output, solving or creating some issues! And further, the stock system operates on a reheat basis, using the hot engine coolant through the heater core to add in some warmth to the very cold output of that 80 000 BTU cooler. Since we don't want to waste the energy cooling and reheating, a large loss of capacity in the stock cooler will actually be wanted in order to not frost the preserves. yes, there will be noise issues, but the fun is in trying it out! Who knows, once the thing is throttled back, the big fans won't have to run nearly so fast, quieting them considerably, maybe replace them with smaller ones even, the compressor won't be running nearly flat out, and as for adjustments to the cooler, wonder what the effect of backing off all the variables will have? hit it right, and no adjustment needed... First guy who cut off a perfectly good bus roof was called a fool by many... Yup, we're flying by the seat of our pants out here now, eh? happy coaching! buswarrior | ||
| Brian (Bigbusguy)
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Have you run your Condenser blower motors with your motor not running? I did on my 4905 had to bybass and A/C run relay to get it to come on . Its loud and I run it also on 12 volts to see how fast it would run its not as loud but you would still be run out of any camp ground you tryed to run your system. I was looking in to useing my condenser motor for a genset raditor cooling but the amps it was drawing was so high I would need a extra genset just to run it. Also GMC had in station cooling if ordered. just like air planes a big tube hooked to a A/C Heat unit mounted some place in the station. Try this wait till the bus is hot inside start it up on low idle and see how long it takes to cool it . I would see if it will even cool at a low idle and take a RPM reading of the compressor and you would know how slow you could run it I would think if you run it to slow it will not work you will lose to much PSI and have no cooling and possably dammage the compressor. Also YOU cant not use the HP numbers from a Home type air compressor motors they are fake. A 5 or even the more fake 6 or 7 HP air compressor motor would not even turn over you bus compressor .Your needing a real industral motor single phase 1725 rpm 5hp at a min you would probley blow the brakers at most campgrounds when it started. Then you want speed controlers? Your going to have more $$ in this then the space shuttle. Just buy a basement A/C and duct the cold air into your bus ducts. Spend your $$$ and time on your converson. Yes you can make it work but at what cost and why? Buy a motor bolt it to 2X4 take you belts off find a belt loop it over you compressor hold it up by hand and see if it will even turn it .Then you can move on to other projects. There is a lot of smart people on this board and when 99% say you a fool for trying it wont work Id listen and save some $$ and headache. if it could be done it would have sorry to burst your bubble . You would do good just to run a car type A/C with a electric motor. Brian 4905 Klamath Falls Oregon | ||
| James Maxwell (Jmaxwell)
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50 amp service in a park is 2 legs of 110v ea, actually giving u 100 amps of service at 110v. The hookup is 220v. 30 amp service is a single 110v line, 30 amps. | ||
| gillig-dan Rating: N/A |
Brian, I believe I was the one who said I would consider a motor speed controller. I already have the AC drive collecting dust in my garage. It converts single phase power to three phase. There is external speed control available through a potentiometer. All I would have to do is monitor my incoming current and vary the motor speed with a rigged up automatic control, keeping the current to a safe level. My objective would be to plug into anybody I visit and steal up to 20 amps from their wall. My bus is a vacation / going visit'n vehicle. When running the 5KW generator, I could increase the current. I am also considering always running from an electric motor and not bothering with the engine drive. The drawback there is running the gasoline generator full time to keep the air going. I have more than enough inverter power to meet any other 110VAC demands. This is the best thread I've found on this so far... Gillig-Dan | ||
| Brian (Bigbusguy)
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Dan, I would think going all electric would be a simpler way to go . A single phase motor is a 3 phase motor it just needs the capasitors to make up for the missing leg mainly for start up. You can shut off one leg of a 3 phase motor after its running and it will run fine not drawing any more amps on the other 2 legs then with all 3 it just will not start with 2 legs. I would think your inverter would run a real 5 hp motor (they are 3 times the size of the home depo type 5 hp air compressor motors) if it was sized right and your bus alt would keep it running down the road. I think it would be cool to say look at this A/C sys. if you get it to work. But for me Id take the money you would spend and buy a new car or Hog. Or a new Marthon Coach. I too hated to remove a completley rebuilt A/C bus air in my 4905 that worked realy good.. But the 1500 lbs of crap and space it took up was better to have it gone for a RV converson. Im going to take apart window A/C's and build them onto my coach. 2 under the rear cap one for the bed room the other for the living room ducted in the over head cabnets the other one in the old A/C compartment ducted to the driver area. All run off my inverter so when driving the bus Alt will keep them going . No roof tops for me. Brian 4905 Klamath Falls Oregon | ||
| Richard Bowyer (Drivingmisslazy)
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Brian, when you remove one leg of power from a three phase motor, you loose at least 33% of its hp capacity. Richard | ||
| Brian (Bigbusguy)
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Richard I did not have any way of checking the HP but when I removed one leg while it was running the Amps on the other legs should have gone up or the motor with a load slow down. It run fine no slowing or any increse of amps on the other legs. Maybe on paper it may show a 33% loss but testing in the field on a loaded running 3 ph 480 volt delta Y 3 ph ,10 hp motor showed no loss in hp or gain in amps or any loss of speed . Same on any of the legs as long as 2 was hooked up. Now the same motor will not start up on 2 legs. You may be right but this is what I saw and done. I dont have 3ph here to go out and retest what I did 10 years ago. Brian 4905 Klamath Falls Oregon | ||
| FAST FRED Rating: N/A |
"By James Maxwell 50 amp service in a park is 2 legs of 110v ea, actually giving u 100 amps of service at 110v. The hookup is 220v. 30 amp service is a single 110v line, 30 amps." James gives the correct theoretical answer that is actually correct in brand new destination parks. However many Old established campsites merly use 2 legs of the "old" 30A service to advertise 240V in the camping guides. Have even been in one place that had 240V at 15 A per leg. The "proper" 240 plug is NO guarantee of amperage. FAST FRED | ||
| John that newguy Rating: N/A |
James- "50 amp service in a park is 2 legs of 110v ea, actually giving u 100 amps of service at 110v." Near all the camps we've stayed at have had only 30 amp service. Those that have had 50amp service were the "220" volt variety and provided essentially two 110v legs at 30amp each. Plugging your 30amp shoreline into the 50 amp plug (using adapter) would not gain you any more amp capacity that had you plugged into a 30 amp plug. It's still 30 amp per leg. At a few parks where I did check, the breakers were 20 and 30 amp, one for each leg, to provide that "50 amp" service. I never bothered to check all parks, but I feel "real safe" to assume that "50 amp service" is the total amps you may be lucky enough to get for that doubled 110v service you're using and you'll be real lucky to get a full 30 amp at either leg. And in many cases (as FF stated), many parks have terminated two 15 amp 110v services in a 50amp receptacle to claim they are able to provide service to those with 50 amp service plugs. | ||
| truthhunter@shaw.ca
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So do I understand correctly , I should not count on any 220 service if I stop over at camp services, does this mean it is not like a 50 amp house stove plug were you can get 110 and/or 220 volts (by runnig both 110 hot wires=220 volts) Sould I keep my maximum single "appliance draw" or circuit at 110 volt and under 15 amps at a campground. | ||
| John that newguy Rating: N/A |
Say Huh......? They don't advertise "220v service available", they advertise "50 amp service available". Your 50 amp power plug feeds the 110/110 service from that 50 amp outlet into two legs of your system, each leg supplying whatever you have them connected to. In many parks, there is a 20 amp and a 30 amp breaker for that total "50 amp" service. That means one leg of your service will be limited to either a 20 amp or 30 amp draw. In some older parks, they simply took two standard 15 amp feeds and fed them both into a 50 amp outlet. You can run both airs, if they're one to each leg, and perhaps another appliance... I wouldn't assume you can run any 220v appliance via any park's 50 amp service. That's not what they advertise or guarantee. In fact, many RVrs do not realize that 50 amp service outlet is actually nothing more than a standard 220 volt outlet, or that the power entering into their RV is actually divided into two separate 110v circuits. The genset supplies that same effect and is why, with a 30 amp configuration, you can run two AC units when plugged into the RV outlet running from the genset, but can only run one ac unit when on shorepower. | ||
| gillig-dan Rating: N/A |
Brian said earlier... "But for me Id take the money you would spend and buy a new car or Hog. Or a new Marthon Coach." What was that line I read on here a couple weeks ago?... "I'm so tight, only dogs can here me fart" I was thinking of going the electrical and mechanical route because I'm a cheap SOB. I am building my AC system from scraps of this and that. Plus, half the reason to do this is to feed my "I did it myself ego". I would like to run on inverter power but, from what I've read on this board, modified sine wave inverters are not too efficient running motors and I can't afford a sine wave inverter. Another reason to run off the motor when moving is so I can create more cooling power. When parked, I'd like to be able to cool the bus on single phase 110VAC power. This has me thinking (oh no, not again you say) that I may take a suggestion I saw in another thread on this board. Why not use a hydraulic pump (power steering type) to get the power from the engine and use a hydraulic motor to spin the compressor when the engine is running. That way, I could move the electric motor and compresser to the generator bay, where there is plenty of room and my air conditioning hose connections could be shorter. I could valve the hydraulic motor in and out of the circuit instead of a clutch. And use a simple belt tensioner system to switch between the electric and hydraulic motors. The problem is, I know very little about fluid power but, if I stay at the Holiday Inn tonight... Anyway, does anyone know how many horsepower I could generate with an average automotive power steering pump? Is there any chance that power steering pumps can run as hydraulic motors? I was figuring I could pick up power steering pumps cheap and a matched set for pump and motor would make figuring the RPM's easy. I would like to hear some thoughts on this, Gillig-Dan | ||
| John that newguy Rating: N/A |
Dan- Why not figure out a way to run automobile air conditioner systems using an 110v electric motor? If you can manage to spin that automobile ac compressor with an electric motor, you can use the centrifugal pulley arrangement to couple the whole mess to the bus engine. Use as many car systems and electric motors you need... Hell, you can even set up an inexpensive lawnmower engine to run the things... Or........ How about this: http://www.aaroncake.net/circuits/inverter.htm and just use converted, modified home window units.... | ||
| John that newguy Rating: N/A |
Dan- Hey: http://theepicenter.com/tow082099.html | ||
| ChuckMC9 (Chucks)
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Woot - that's a Hoot! how could you hear the TV with the lawnmower engine right there??? LOL  | ||
| Jtng Rating: N/A |
And now for BRAAAAAAAAAAAAAAAAAAAAAAAAPPPPPPPPPPttt the news YAPYAPAPAYAPAPAYAAAPAPABRAAAAAAPPPP | ||
| Johnny Rating: N/A |
Not really...the newer ones, especially Honda, are nowhere near as loud as the old ones. Even the new Briggs sidevalves are much quieter than even 10 years ago. | ||
| James Maxwell (Jmaxwell)
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I stand corrected by the caveat that FF brings up. Yes, even I have found exceptions and that includes hots connected to neutral lug on 220 service. I have heard of the 20/30 hookup but have never encountered it. The vast majority of parks that I have stopped in have the services that I described originally. If u really want to see exceptions, go to Mexico. That is why I always meter the service before I plug in unless the service box looks fairly new and un-damaged in any way. | ||
| FAST FRED Rating: N/A |
"Sould I keep my maximum single "appliance draw" or circuit at 110 volt and under 15 amps at a campground." If you wish to camp totally hassel free , THIS is a good plan. New destination ($$$$) parks cater to the newbees in their tiny electric rolling home , with the 5 slideputs, but the older the campground , the LESS chance you have at HUGE electric. Unfortunatly all the really pretty places that offer great locations were built decades ago , when 15A ran a perc pot or TV. Today the new destination parks that have Great Electric , frequently come with METERS at every site. At 15c a KW its still cheaer than running a noisemaker , but a bill at checkout , after a long wait for the meter reading is becoming the norm. Too many jokers coming into do loads of laundry with drying while running a series of air cond ,the campground cant rent a site for $30.00 and see $25 worth of electric used. 15A and NO FEAR , in US or Canada. Works for me, FAST FRED | ||
| Johnny Rating: N/A |
This has been said, but it's vital enough I'm repeating it: especially at an older campground, check the voltage before hooking up! I've seen it as low as 100-105 volts, & this is bad news for plenty of stuff. While I've never seen it personally, I've heard of 130-135 volts from some people, which is also bad news. | ||
| gillig-dan Rating: N/A |
Any takers on the question I asked above? (repeated here).... "Anyway, does anyone know how many horsepower I could generate with an average automotive power steering pump? Is there any chance that power steering pumps can run as hydraulic motors? I was figuring I could pick up power steering pumps cheap and a matched set for pump and motor would make figuring the RPM's easy." I'd rather not put the electric motor in the engine bay. It makes a lot more sense to put it in my former spare tire bay with the generator. JTNG, re-read through the thread (it's getting kinda long and it was Truthhunter who started it, I just came along for the ride), you'll see I already have most everything I need to put together a properly sized system for my needs. I also don't feel comfortable running a large motor from a square wave inverter. Gillig-Dan | ||
| truthhunter@shaw.ca
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Well I guess that "campground power avalable" fact about puts a end to my feasability study then. It sounds like all one could expect to run is one 15,000 rooftop and a few small appliamces. I guess if I want to make the factory AC more useable than just "rolling mode" I would be best to move it and run strait off an oversized diesel generator that was quite enough for camp grounding. It might be practical to hook in a smaller electic drive A/C compressor to the existing factory evaporator/condensor setup if the MC 8 vents were reconfigured into a more efficent hi/lo (hi for A/C & lo for heat) delivery system. Something that I may do if I end up using a diesel fired Air-to-Air heating instead of the more expensive hydronics. I will keep you all informed with the finsihed contraption as pay for all your considerations. (more like I will continue to consult with you all during my habitual re-inventing of the wheel-the story of my life-allways in everyway-but then I think I am in good company) Keep on Exploring Everything, Everywhere Everyone as the only thing humans have ever truly create is though, all other efforts were merely changing the state of what already exist. | ||
| Ron Walker (Prevost82)
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gillig-dan ...I think that a standard automotive power steering pump would not have the pressure or flow that you are looking. I think they only put out around 1000 PSI and may 10 GPM. The other problem is they are not as efficent as a elec motor. You didn't state if you were piecing together a A/C unit using your bus compressor or a car A/C compressor...if you are using the bus compressor you would need a large pump and motor (30 hp) and cooling system, which would cost more than a inverter and elec motor. This is not the best application for Hyd's. Ron | ||
| Brian (Bigbusguy)
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The power steering pump will put out the PSI but the flow would be to low to run a hyd motor of any size to run your AC . They do have pto driven pumps to run hyd driven air compressors but when you see the size of the pump you would see why a power steering pump will not work or last long. Brian 4905 Klamath Falls Oregon | ||
| gillig-dan Rating: N/A |
I'm trying to run a 10 cu. inch York compresser. It's rated up to 30K btu's. I figure the hydraulic pump should be rated for about 5 horsepower. There are several factors making me not want to use the engine bay for the AC compresser and auxillary electric motor. The problem I'm having is spec-ing out a hydraulic pump and motor combo to transfer the power up to the front bay on the bus, where I have plenty of room. As far as costs, once I decide what I need, I'll scrounge up the parts from somewhere. Does anyone know what the actual efficiency rating is for a small hydraulic pum? I was hoping Phil Dumpster would weigh in on this. It sounded like he was planning a similar system based on another recent thread on this board. Gillig-Dan | ||
| Ron Walker (Prevost82)
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Hi Dan...You would have find out what HP & torque & speed (of motor) is req'd to run this compressor ...not "guess" or "figure". Then phone an industrial supply shop that handles hydraulics and give them the info req'd for the compressor as well as the speed range of your diesel motor and they will tell you what size of pump and motor is req'd. The actual efficiency of hyd. pump & motors & will vary greatly depending on, what type of pump and motor you use. Gear pump & motor aprox 75% (cheap) Vane " " " 85% (more expensive) Piston " " " 95% (very expensive) " pressure compensated(xtrem expensive)but little heat. Then there's the plumping (how many turns, line size, heat etc. It all plays into the equation. Like I said this isn't the best application for Hyd's. You will be looking at some pretty high flow rates and pressures. Ron | ||
| Tom Caffrey (Pvcces)
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Gillig-Dan, I don't think you're going to have much luck using power steeering pumps in your air conditioning. I think that they're only fractional horsepower. The last hydraulic systems that I had any real experience with had losses of 25 to 30 percent, as I recall. This means that if you need 5 horsepower to run your compressor, you will need to get rid of a couple of horsepower (5,000 BTU per hour). That and reliability problems are the main reasons that the makers went with mechanical drive. Keep in mind that they were dealing with 8 to 10 ton systems. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| Johnny Rating: N/A |
What about one of the big PTO hydraulic pumps (crank-driven) from a trash truck or recycler? I can't imagine they'd have any trouble running a bus A/C even at 100% capacity. Offhand, I've seen them bolted to 3208, 3126, and 3406 Cats, B and C-series Cummins, International DT408, 466, and 530's, 6-71 Detroits, 855 Cummins big-cams, Brazilian Ford 6.6 & 7.8's, & several Macks. | ||
| FAST FRED Rating: N/A |
My book for Blissfiels (formerly Tecumsa ) HGB -1000 10,35 cu in compressor shows 500 to 3000rpm at 3/4 to 5 hp. The climate control (Formerly York/ Borg warner) ER210 compressor also 10.35 cu in (aluminum) gives 500 to 6000rpm at 1-5hp. This is from thw www.refparts.com parts catalog. Most power steering pumps would be lucky to be 1/2 hp , so a complete hyd system would be needed to turn a compressor. Switching electric to hyd only incurrs a high parts count and low efficency. IF you want very efficent air cond and gen sets , check out Glacier Bay , but top level Marine goodies are not priced like OTS RV stuff! FAST FRED | ||
| Johnny Rating: N/A |
5HP from a PTO hydraulic pump sounds, if anything, low, considering the loads these things are designed to run. They aren't hard to find at big-truck junkyards. |