Mep804a 170v on output terminal?

[319cssb]

The generator puts out electricity at 60hz but 170v to the L's and neutral. Can someone give some advice on how to manage the voltage down to 120v?

 

[Scoobyshep]

Going to assume you have tried the voltage adjust knob, are you relying on the set gauges or a digital meter?

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[319cssb]

Voltage knob does nothing. Im reading voltage from gauge and multimeter 170v output at 60hz . I dont know how much rpm, but I would like to check it

 

[Scoobyshep]

Rpm and frequency (Hz) are directly related. If the rpm was wrong then the frequency would be off as well. So there is no reason to check rpm.

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[319cssb]

My voltage knob differs from the part number in the tm 9-6115-643-24
There it calls for a RV4NAYSD203A mine is however RV4LAYSD203A. Does that matter? Because the results I get differ from the results I should see as per TM

 

[319cssb]

Rpm and frequency (Hz) are directly related. If the rpm was wrong then the frequency would be off as well. So there is no reason to check rpm.

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That fact makes sense to me as well, I like to just double check it from the RPM i should be seeing

 

[Scoobyshep]

Cut sheet says that the 4th digit is the bushing. N is a standard L is a locking.

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[319cssb]

Hmmmm I didn't notice a locking action. Are you supposed to pull on it to lock?

 

[Scoobyshep]

Couldnt tell you. The important things are the power rating and resistance. Odds are you are barking up the wrong tree. Follow the procedure in The TM, there should be something for high voltage or how to test the voltage regulator. I have very little hands on with the 800 series, something simple to look at is is this unit in a parallel mode? It could be looking for an external source for voltage regulation.

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[319cssb]

It was in a parallel mode once.
Got anything on your mind , I ahould look for?

 

[Guyfang]

Here is the listing for the gen set volt regulation system. Normally, Scooby's suggestion in post #9 is the one I would make. Follow the TM.

BUT, the military, in its infinite wisdom, procured TWO different Volt Regulator systems. One made by Libby. One made by TRC. Sooooooooooooooooooooooooo, you need to look at the attached list, and then the V1, (volt regulator). Note the manufacturer, and then look at the rest of the listed numbers on the list. You can not mix and match parts. All have to be from the same company.

 

[Guyfang]

My voltage knob differs from the part number in the tm 9-6115-643-24
There it calls for a RV4NAYSD203A mine is however RV4LAYSD203A. Does that matter? Because the results I get differ from the results I should see as per TM
View attachment 801979

OK. Did a little research. Both the RV4LAYSD203A and RV4NAYSD203A are 20 ohm variable resisters. Are you testing without removing the wires? If they stay hooked up, then your reading will not be right. If the name on the A1 is not TRC, then they do not match.

 

[319cssb]

Yes, Guy my A1 is made by TRC and i replaced the mosfets with new ones, but same results.

I will check out that voltage reostat again.

 

[Guyfang]

And the A1 is hooked up like this? Also you need to look at the other parts on the list, to see if your whole system is TRC.

 

[319cssb]

I'll check the wires tomorrow, thank you for that link Guy. Will also check the other parts