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7500EXL GENERAC GENERATOR NO AC OUT

cutnshoot84

Sep 19, 2013
5
Joined
Sep 19, 2013
Messages
5
I got this from an uncle and the motor starts and runs perfect. I does not put out any AC from the receptacles. I was going to buy a voltage regulator board but would like to ohm the brushes/stator before spending the money. The stator looks like got a workout but don't see the wire broken. I know that you can start it and take readings from the brushes and the stator. I am uploading a pic or two and if you could talk me thru it I would appreciate it . Can you highlight the wires to measure across and tell me what the readings should be. I have worked with electronics and know you can get in trouble quick and know the dangers involved . I wont hold anyone accountable.

1 I know the reg. board is in top middle. Is there a way to check it? Do I need to unhook it to check the outputs?
2 When I measure across the brushes what should it be and do I need to disconnect the EVR?
3 The 2 sets of wires bottom left are in original configuration and the yellow set was the inner set. What wires should I touch meter leads with and what should the readings be.

I would greatly appreciate any help.
 

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shrtrnd

Jan 15, 2010
3,873
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Jan 15, 2010
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3,873
Let's start with the dumb questions first:
Did you check the fuses?
 

duke37

Jan 9, 2011
5,364
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Jan 9, 2011
Messages
5,364
First determine the type of generator.

What is the specification.
If it is AC out, then there is likely to be a good connection from output to the stator windings. Check the stator windings for continuity.
Check any fuses between the stator and sockets, as recommended previously.
Look at the brushes, do they contact a commutator or a pair of slip rings?
Is there a good connection between the brushes as the rotor is turned gently?
 

shrtrnd

Jan 15, 2010
3,873
Joined
Jan 15, 2010
Messages
3,873
Google the problem, I found the following, which may or may not help:
Good Luck

The most likely scenario here is that the battery charge rectifier (BCR) failed, allowing 12V to backfeed through the battery charge winding of your stator, causing the rotor to become demagnetized. The short solution is to flash the field to restore residual magnetism.
However, if your power regulation board (PRB) has also been compromised, you run the risk of a complete meltdown of the stator if you flash the field. What I always recommend before flashing a field, is to test the integrity of the generator t make sure we will do no further damage. I have melted 2 stators in this manner, and it cost me a pretty penny.
The test are very simple and do not require much time.
First, when removing the wires either take notes or make a drawing to ensure they get put back in the proper place.
Disconnect the 66 and 77 wires from the BCR.
Disconnect the 2 and 6 wires from the PRB located behind your control panel.
If your set is equipped with the second BCR, disconnect the 66A and 77A wires from it.
Disconnect the 11 and 44 wires at the idle control transformer located behind the control panel. There are (2) 11's and (2) 44's. Make sure you disconnect the ones coming from the stator.
Disconnect the 22 at the 50A receptacle.
Disconnect the 55 at the 12VDC receptacle.
Set your meter to ohms and test across the following:
66-77 about 0.1 ohm
66-ground infinity
66-2 infinity
66-11 infinity
66-22 infinity
2-6 about 0.5 ohm
2-ground infinity
2-11 infinity
2-22 infinity
11-22 about 0.1 ohm
11-ground infinity
44-22 about 0.1 ohm
 
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