1997 Fermont 803a

[Buster1528]

There are a couple others not marked, but all in all, not many.

Do you know what those 2 are

 

[Guyfang]

For instance:

The shield wires in the control panel. They go to the A1 Ground point.
The white and black wires from the CB-3, in the control panel. Should be 4 wires.
The three wires on the L5.

That should be it.

 

[Buster1528]

Does anyone know what these two wires are identified as? they are attached to the back of that aluminum terminal block. One was fully connected the bottom wire was broken barely making a good contact? I want to test the stator those wires are hooked to. But I can't identify what wires are which. Not sure which wire gets positive and what wire gets negative from the meter. TM says connect meter to F1+ and F2- stator leads but the leads are not marked.

 

[Guyfang]

They should be F1 and F2.

 

[Buster1528]

I have been working on my mep803a trying to figure out why it's not making power I noticed its missing that blue resistor if that's what it is. Where can I buy one?

 

[kloppk]

The blue device is a MOV Metal Oxide Varistor better known as a surge protector. It's there to help protect the VR from voltage spikes from the Quad Winding which can cause the VR to short out damaging the Quad winding.
I have them available. PM me and I can send you one.

 

[Guyfang]

Did you test that big fat fuse that is next to the A1?

 

[Buster1528]

Did you test that big fat fuse that is next to the A1?

Not yet been raining like crazy here. Been trying to read up on all these testing procedures. But definitely will. Borrowed my buddies ohms meter. I think someone swapped the vR out especially after seeing it was missing that surge protector. I'm getting anxious because I want to figure this out. Thank you for your assistance.

 

[Guyfang]

The Varistor was not standard issue to the set. It not being there is "normal". But still needed.

 

[Buster1528]

Started testing voltage regulator tested between 104c and 105 voltage comes out to 7.60 spec in book says it should be 8. I have the generator set in 3phase 60 hrtz and the the out lug is saying 26.2 volts

 

[kloppk]

7.6 volts there is exactly correct. TM says "approximately 8 VDC". 7.6 VDC is what I measure on my good working set.

Measuring 7.6 indicates the "flashing" circuit is working and you have continuity from there to the exciter and the exciter is receiving the voltage.

What voltages and resistances do you get with the other VR tests?

 

[Buster1528]

7.6 volts there is exactly current. TM says "approximately 8 VDC". 7.6 VDC is what I measure on my good working set.

Measuring 7.6 indicates the "flashing" circuit is working and you have continuity from there to the exciter and the exciter is receiving the voltage.

What voltages and resistances do you get with the other VR tests?

Between T3 and T4 126.7
T7 and T8 000
Voltage adjustment test Nothing

 

[kloppk]

Between T3 and T4 126.7

That's good. It indicates the exciter is working, flashing the gen head and the gen head stator is putting out AC voltage.

T7 and T8 000
Voltage adjustment test Nothing

That's not good.
When you did the test did you disconnect wire 156A from the VR and then measure the RESISTANCE between wire 156A and terminal 2 of the VR while rotating the AC Voltage adjust knob?

 

[Buster1528]

Between T3 and T4 126.7
T7 and T8 000
Voltage adjustment test Nothing

T3

That's good. It indicates the exciter is working, flashing the gen head and the gen head stator is putting out AC voltage.



That's not good.
When you did the test did you disconnect wire 156A from the VR and then measure the RESISTANCE between wire 156A and terminal 2 of the VR while rotating the AC Voltage adjust knob?

Yes

 

[Buster1528]

T3

Yes

My mistake there are digits while testing

 

[kloppk]

OK, that would indicate a problem with either the wiring from VR terminals 1 & 2 to the voltage adjust potentiometer on the front panel or a problem with the voltage adjust potentiometer itself on the front panel.

Just to re-verity. You measured 126.7 volts AC between VR terminals 3 & 4 with S1 in START. Correct?

 

[kloppk]

And 0 ohms resistance all the time when you disconnected wire 156A from the VR and then measure the RESISTANCE between wire 156A and terminal 2 of the VR while rotating the AC Voltage adjust knob?

 

[Buster1528]

OK, that would indicate a problem with either the wiring from VR terminals 1 & 2 to the voltage adjust potentiometer on the front panel or a problem with the voltage adjust potentiometer itself on the front panel.

Just to re-verity. You measured 126.7 volts AC between VR terminals 3 & 4 with S1 in START. Correct?

Yes

 

[Buster1528]

That's good. It indicates the exciter is working, flashing the gen head and the gen head stator is putting out AC voltage.



That's not good.
When you did the test did you disconnect wire 156A from the VR and then measure the RESISTANCE between wire 156A and terminal 2 of the VR while rotating the AC Voltage adjust knob?

My mistake it is giving a reading when I rotate the adjustment knob

 

[kloppk]

It should have varied from around 0 to around 5,000 ohms. Was it generally in that range when rotating it from stop to stop?
The meter may have read something like 4.98 K instead of 4,980 ohms for instance.