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Laman

Onan 7500 CB Not Re-setting

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7500 onan quiet diesel in a '98 American Eagle.

My original problem was that the rear A/C was not working on the generator, but was working on shore power. I tested the input at the automatic transfer switch and found power coming in on leg 2 but not leg 1 with gen. running. Then while the gen. was running I turned the 35amp circuit breaker at the gen. off and now it will not reset! Do I have just a bad CB on the gen or is that a sign of other problems?

The gen. motor starts and runs fine with no issues. I thought I read somewhere that if an Onan was not producing electricity it would shut down, is that true?

Problem solved in #4 post

Edited by Laman

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Hi Laman ! Welcome to FMCA!

Could you post the Model number and the number of Hrs. on your generator for the group ?

The units built up to around the late1990's used brushes on the pickup of the 110 volt Alternator and they do wear out over time. Could be an issue on the one leg.

When you mention resetting the 35 amp circuit breaker. Do you mean the breaker will not stay in the on position or you just do not get a voltage when its reset?

There is a small fuse under the circuit breaker panel that protects the DC field circuit and the rectifier circuit for the voltage regulator circuit.

Read the post on this link and see if some of the information is close to what you have.

http://community.fmca.com/topic/5332-onan-10hdkag-61731x-generator-has-low-voltage/

Rich.

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Rich,

The generator is a 7500 quiet diesel model no. hdkaj 11451d with only 610 hours. I have owned the unit for 18 months and have been religious about exercising the gen. because it only had 400 hours on it when I bought the Eagle.

The issue with the circuit breaker was that it would just not reset and actually a couple of times before it took a couple of try's before it would re-set. I removed the CB this morning, the toggle on the breaker has no resistance and has something rattling inside so I have ordered a new one, which should be here tomorrow. Hopefully this will solve this issue. I did check the 25 amp fuse behind the panel and it was ok. I did see a another smaller fuse holder in the wiring behind the circuit breaker but have not checked it yet.

As for as the original problem of missing power on one leg you mention brushes wearing out, is this something that I can inspect/check on my own or will it require dealer service?

Thanks in advance

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Laman,

Last part of your post:

As for as the original problem of missing power on one leg you mention brushes wearing out, is this something that I can inspect/check on my
own or will it require dealer service?

The model generator you have should have an induction coupling for AC not the brush system.

With only 600 plus hrs on the Generator, I would look for loose connection issue outside the generator.

A rattling circuit breaker is not good. So you should get back one side of your 120 volt AC.

Look for the J Box that connects the generator output to the feed going to the transfer switch. I'm thinking you have a loose connection on 1 or more of the screw terminals in that Box.. They loosen up at times and can ark or burn off the wire that was or still is connected at that point.

Wish I had enough picture attachment space left for a sight you do not want to see under the J Box cover.

Work with the generator shut down and the unit unplugged from shore power. The J Box if often located on the firewall above the generator or in the area. Look for a pig-tale from the generator. If the connections are good and tight, then check the connections inside the generator, then look at and check the connections at the transfer switch used to switch from shore power to generator power.

Rich.

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Well the problem is solved!

The breaker on the gen. had two legs one part obviously bad hence my original lack of power to the rear a/c.

The breaker obviously went totally bad when I was dealing with the lack of power so that created the no power at all issue. I installed a new breaker this morning and what do you know we have power! All 120v items are working fine with more that one hour of running every appliance simultaneously. Only cost $100, much less than I was anticipating

Rich thanks so much for the help, these forums are worth real money.

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