BNO BBS - BNO's Bulletin Board System
TOPICS => THE BOARD => Topic started by: zimtok on August 26, 2013, 08:55:25 AM
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My charging system decided to not charge ...
I have the original generator and voltage regulator with positive ground.
Usually when the engine RPM comes up a little it kicks in the charging but now it doesn't.
I can force the relays inside the BIG voltage regulator and get it to start charging but it kicks out again.
Any Ideas wheat to start looking for?
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zimtok
In my GM (fishbowl) it has the same charging system where you rev it up to start charging. There is a generator relay and a generator sensing relay with a large resistor. Check your output on the generator to see if it is producing and how much. I'm sure somebody with a 4104 will chime in to help as you may have a slightly different system.
Bill
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Are your batts fully charged?
Is one of your batts shorted? This has happened to me a couple of times. Apparently a hazard of multiple batt hookups.
I had to replace field relays on both my 4104 and 4107.
I think they wear out at the relay points because they are overworked due to the small loads we have compared to the heavy loads with many passengers, especially with the original bus AC.
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Both Batteries are good ad fully charged.
I did remove one battery at a time to see if it was a battery.
I also made sure the batteries were fully charged with a battery charger. and checked each cell voltage to make sure I didn't have a bad cell on either of the batteries.
About a year ago I cleaned the contacts on the relays because they were arc pitted and it would sometimes not charge. But the relay would pull in and not charge. I cleaned them this time just to be sure but that didn't help.
The relays are not pulling in.
If I push the actuating relay in and then the circuit breaker relay in it will start to charge until the RPM's of the engine drop or after a few minutes running at high idle but then it drops out and will not engage when the RPM's increase again.
If I hold the relays and force it to stay charging I think it may be over charging because the lights are a lot brighter then usual.
(I need to check voltages)
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the section on adjusting the gen in the 4104 manual is long and relatively complicated. It will take a couple of readings to digest. I have not digested it as I dislike gens and put in an alt. I messed around with gens for a couple of years in old cars and they tend to be challenging. Not too many folks are up on gens any more, but if you find the right source (or electronics hobbyist ) you will get it. FWIW your problem sounds minor "ish" as you can still force charging.
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Have you energized the fields of the generator some call it flashing ? If I remember right the regulator cannot be grounded on the positive ground system at least on the heavy equipment with the + ground it wasn't
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Have you energized the fields of the generator some call it flashing ? If I remember right the regulator cannot be grounded on the positive ground system at least on the heavy equipment with the + ground it wasn't
There was a short between the bus 12vdc positive ground system and the generator 12vdc negative ground system. This happened up in the generator compartment (old air conditioner compartment)
What would happen if this did "flash" the field windings? and what do I do about it if it did?
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I did a check on the generator.
I put a volt meter positive lead on the ground, negative lead on the Armature post.
Started the engine and brought it up to charging speed.
Jumped out the field terminal to the battery cable.
The reading on my meter was only about .5-2.5vdc
I guess I need a new generator.
I have been thinking about going to negative ground and an alternator.
What is involved in going to an alternator?
What do I need to do to make it negative ground?
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You do have an alternator now don't you? I didn't catch what model it is but I assume it's an alternator???
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Positive grounds were generators,changing all the grounds wire to negative takes a while but doable the starter doesn't even need changing just moving the cables from positive to negative on it, blower motors some yea and sometimes no depending on the motor
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This is a 1960 4104 with the original positive ground and generator.
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Does it have the same drive gear setup as a 50dn or is it a big process to change to one?
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The generator is a direct drive from the bell housing, no pulleys or belts.
It is air cooled not oil cooled.
I don't know how the 50DN alternator is configured so I can't answer your question.
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The Coach Information Network has a booklet for a 4104 with positive ground and a generator that shows step by step how you change over to negative ground from a positive ground the 20 bucks is well spent IMO saves a lot of trial and errors on ones part
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The 50DN on a Detroit appears to mount exactly the same. While the generator IS air cooled it gets it's air from the air intake system where the engine air filters are mounted through a flex hose about 2 1/2".
The 50DN is totally sealed and has an oil line going to it from the engine. The oil drains back through the drive gear housing.
The conversion from pos ground to neg ground is not hard. There was a procedure in the archives, maybe still there. You also have to make a change in the alarm relay. It has selenium rectifiers in it. I just changed to diodes (& changed polarity) in mine, works great.
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Me I would belt drive the alternator off the cam shaft with a auxiliary pulley in that mounting place, a gear driven 50 D alternator is just a time bomb waiting to go off it's not pretty when they do go off lol
There is no need for a 300 amp alternator 145 to 170 amps will do anything you ask for and with some left over
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I had a 1960 PD-4104 that had a 50DN oil cooled alternator from the factory as a option.
It also had the electronic voltage regulator.
Worked for many years with out any problem.
I sold the coach and the new owner converted the coach over to neg. ground.
Contrary to what some folks say the 50DN is a very trouble free alternator.
And yes you can put a 50DN alternator on your 4104 if it has the old split field generator.
The adapter can be found on some of the old early MCI 8's that were ex Greyhound coaches if my memory is correct.
Or you can put a belt driven single wire 100 amp alternator on the old 6/71 gear case by adding a belt drive pulley where the old split field generator was located.And building a mount for the alternator.
jlv
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To each his own about durability of the 50DN the adapter plate is common to any DD not a bus model it has 2 adjustment screws while his cam drive will work it is not the right one
The belt drive is the way to go centering the drive can be a PITA it takes me about 2 hrs to set up a 50DN the correct way you can slap it on a go but I don't
I have saw first hand what can happen when the 50DN turns loose and takes the gear train out JMW
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I think I still have a voltage regulator for a 140A 12v positive ground generator if anyone needs it. It is free for the freight costs. I don't know the condition of it for sure, but I would assume it is good as it came off of a PD 3751 that was running until the engine blew. The bus had belonged to a wanna be band and was sitting at Emmerson GM Diesel in Seattle in the 70's where my dad bought it cheap for parts (we needed a door for our / my current coach after a car ran into it). I don't have the generator itself anymore. We were going to put it on our bus, but when I rebuilt the engine for mom and dad in the 80's I put a belt pulley drive in the hole and a belt drive 95 amp one wire alternator on it, converting to negative ground. It has worked great all these years, but I am going to put a newer 140 amp unit on it.