Onan mep-017-a troubleshooting

[Ray70]

Looking at the TM, page 41 shows a manual field flashing switch "S", connecting battery voltage to the field flash wires. Is that switch present on your machine and have you tried testing it?
My presumption is that if you have power going to that switch and activating it does not give you temporary voltage ( near normal voltage ) on the lugs, then the gen head probably has an issue.
Regarding no continuity on lug L1, have you tried all positions of the AC select switch? It looks like L1 is only used when in the 3 phase positions, not single phase.

 

[Anden mcleod (mep-017a)]

Looking at the TM, page 41 shows a manual field flashing switch "S", connecting battery voltage to the field flash wires. Is that switch present on your machine and have you tried testing it?
My presumption is that if you have power going to that switch and activating it does not give you temporary voltage ( near normal voltage ) on the lugs, then the gen head probably has an issue.
Regarding no continuity on lug L1, have you tried all positions of the AC select switch? It looks like L1 is only used when in the 3 phase positions, not single phase.

It is present and I have tried flashing the field, and have had no change.

 

[Anden mcleod (mep-017a)]

It is present and I have tried flashing the field, and have had no change.

I’ll check to see if the switch works and check to see if it’s getting voltage.

 

[Anden mcleod (mep-017a)]

Looking at the TM, page 41 shows a manual field flashing switch "S", connecting battery voltage to the field flash wires. Is that switch present on your machine and have you tried testing it?
My presumption is that if you have power going to that switch and activating it does not give you temporary voltage ( near normal voltage ) on the lugs, then the gen head probably has an issue.
Regarding no continuity on lug L1, have you tried all positions of the AC select switch? It looks like L1 is only used when in the 3 phase positions, not single phase.

Is the avr involved at all during the manual flash?

 

[Ray70]

The switch should send DC voltage directly to the generator exciter , power goes to the exciter through Resistors R5 and R6 then to pins 16 and 17 on the terminal board. So I would check for power at TB 16 and 17 first, then work backwards if no power there.
What position do you have the Voltage select switch set to?

 

[Anden mcleod (mep-017a)]

I found someone on Facebook who does generator repairs and he’s going to come and look at it and diagnose it for me. He was a mechanic in the army in the mid 70’s, I’ll update how that goes.

 

[Guyfang]

Attached is your wire diagrams . Look at the TB. Pin 5 goes to the S switch. Pin 7 goes FIRST to the K1, THEN to the S switch. We used to keep a box full of these relays. Dependable, they were not. ALSO, look at the back of the Relay card. See if the solder trace is burnt.