| Author |
Message |
Tom Caffrey (Pvcces) (65.74.64.127)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 1:25 am: | |
Our generator puts out radio noise when it is putting out power that interferes with AM radio listening.
The thing that puzzles me is that the generator is a brushless design, so I don't see what could be arcing to produce the noise. The generating frequency is so low that it should not show up as radio noise.
As the generator runs, the regulator powers the field on for a little bit, then off. There is no noise when the field is off, but it is present when it is on.
Does anybody have any ideas as to what could be causing the noise?
Thanks.
Tom Caffrey PD4106-2576
Suncatcher |
FAST FRED (63.234.20.132)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 5:46 am: | |
Does anybody have any ideas as to what could be causing the noise?
Couldnt give the tech reasons , but this is common on many coaches and boats and filters are made that work.
Our 06 had the problem and an inline filter just to the radio solved the problem.
West Marine, source
FAST FRED |
pete (64.12.96.105)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 6:49 am: | |
it has something to do with the ground and the output going through the chassie i believe..modern stereos have the same prob if you have it on am and are in an area that has electric lines near the road..
pete |
Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 9:21 am: | |
Just a guess. The alternator is a three phase AC device generating probably around 60-120 hertz output. The output is then run thru a bridge diode to convert the AC to DC. Could possibly be the on-off of the diodes creating the electrical noise.
Richard |
Geoff (Geoff) (66.238.120.24)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 9:57 am: | |
Places like Radio Shack sell noise suppressors that hook up to the positive lead of the radio. Another trick is to wire the hot lead for the radio directly to the battery. |
Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 12:29 pm: | |
In the old days, when generators were actually generators and not alternators, the brushes of the generators created a lot of electrical interference, especially in the AM radio bandwidth. There were actually commutator bars that would made and break the electrical circuit several timer per rpm of the alternator. We used to install capacitors on the output to filter out the noise they generated.
With the new alternators, generally there are only slip rings that provide excitation to the field windings, and there should be no electrical noise generated as the brushes make constant contact with the slip rings.
Tom indicates that his generator (maybe really an alternator) is of the bruslesss design. All of the automotive alternators that I have seen have had slip rings and brushes, so I really do not know for sure. They used to be called brushless, because they did not have the large commutator brushes, but they did have the low current exciter brushes and sliprings.
Richard |
jim wilke (12.46.52.74)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 3:23 pm: | |
Richard, Tom is talking about the large gear driven, sealed, oil cooled alternator. I just R & R'd mine to go through it. It is indeed brushless. It has a little exciter inside just like an AC genset. I guess being sealed & drenched with oil, the brush design didn't work well. Plus, there is nothing to service inside between engine overhauls (bearings) so it doesn't have to come off very often which is lucky 'cause they are damn heavy!
Jim-Bob |
Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 5:21 pm: | |
OK, thanks Jim. I have never seen the inside of one of those and nobody has previously explained that they were total brushless. That is why I qualified my statement that I did not know for sure. Thanks very much.
Richard |
TWO DOGS (66.90.213.86)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 6:35 pm: | |
in my service book....it says under "alternator removal" : remove this bolt,remove that bolt ,GET TWO MEN TO REMOVE THE ALT........oh well...I thought it was funny.... |
BrianMCI96A3 (65.40.154.50)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, December 09, 2003 - 8:00 pm: | |
Yep, damn heavy, and damn expensive...
Which is why I got a good used take off...Just in case the the year and a half old one on the coach now, dies some day.
I THINK I could manage to heave that thing up out of the access hatch but it would be a bear.
Brian |
Tom Caffrey (Pvcces) (65.74.64.127)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 10, 2003 - 1:06 am: | |
Thanks, guys. I heard two ideas that I think I can make use of. The noise suppressor at the radio and the one at the alternator.
I had not thought of the sharp conduction and cutoff of the diodes as creating radio noise right in the alternator. After I try the ideas out, I intend to post what I learn from them.
This board can really be a help.
Tom Caffrey PD4106-2576
Suncatcher |
TWO DOGS (66.90.212.158)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 10, 2003 - 1:35 pm: | |
back a million years ago...I asked a guy,'why is that condenser on the generator...' I think I'm going to go to 100 amp. G.M. one wires....one for the bus & one for the house batterys...that big monster is scary...can just see me stranded & nobody could work on it ,or, if they could,would have to pay WAY too much |
Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 10, 2003 - 4:26 pm: | |
Two Dogs, I had an alternator on my 4104 quit while out on a trip. Stopped at the next town and bought a large battery charger. Started the genset, plugged in the battery charger and continued on my trip. Did not even need the genset during the day as so little DC power is utilized.
Richard |
Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 10, 2003 - 4:27 pm: | |
Two Dogs, I had an alternator on my 4104 quit while out on a trip. Stopped at the next town and bought a large battery charger. Started the genset, plugged in the battery charger and continued on my trip. Did not even need the genset during the day as so little DC power is utilized.
Richard
PS I have always carried a battery charger since then. LOL |