002 Fluctuating voltage

[6869704x4]

Been through the troubleshooting steps in the manuals, all the way to the diodes on the back of the rotor. No fix. Replaced the AC VR with one of Triple Jims units, nice looking piece by the way Jim, still no fix. I'm going to go through the steps again to be sure. If the problem is in the generator itself I'm looking at a Winco 2 bearing 1800rpm gen head. Would need to figure out a way to couple the engine to the generator. Shouldn't be rocket science. Has anybody on here tried/done something that?

 

[Chainbreaker]

Please provide more information on what you mean by fluctuating voltage.

What voltages are you seeing displayed?

Does it produce normal voltage and then shoot up high or low?

Is it intermittently fluctuating or consistently fluctuating?

There are several components that can become intermittent resulting in erratic voltage fluctuations. In addition to the AC VR, there are components located in the "Control Panel" box that can cause fluctuations if they are failing... T1 & T2 transformers come to mind.

Then you have the "AC Distribution" Box that has its large transformers inside.

 

[6869704x4]

Please provide more information on what you mean by fluctuating voltage.

What voltages are you seeing displayed?

Does it produce normal voltage and then shoot up high or low?

Is it intermittently fluctuating or consistently fluctuating?

There are several components that can become intermittent resulting in erratic voltage fluctuations. In addition to the AC VR, there are components located in the "Control Panel" box that can cause fluctuations if they are failing... T1 & T2 transformers come to mind.

Then you have the "AC Distribution" Box that has its large transformers inside.

The voltage flux is constant I'm seeing +/- 60v at least, both at the load terminals and convenience receptacle.
I've checked T1 and T2 and they checked good, but like I said I'm going to go through the steps again and make sure I didn't miss anything.
When I got the set it was working fine.

 

[Chainbreaker]

Also, its a good idea to check the Control Panel box & AC Reconnection box for possible loose connections. I put a screwdriver on every terminal screw to verify they are tight and also perform a tug test on each wire. All it takes is one loose, intermittent, wire to cause problems.

 

[6869704x4]

Also, its a good idea to check the Control Panel box & AC Reconnection box for possible loose connections. I put a screwdriver on every terminal screw to verify they are tight and also perform a tug test on each wire. All it takes is one loose, intermittent, wire to cause problems.

Working on it today, will do that also. Thanks.

 

[Triple Jim]

If you haven't already, I'd check the resistance of CVT1's C1-C2 winding and its X1,X2,X3 windings, as given in the -34 TM.

 

[6869704x4]

If you haven't already, I'd check the resistance of CVT1's C1-C2 winding and its X1,X2,X3 windings, as given in the -34 TM.

Thanks Jim

 

[jamawieb]

I agree with the statements above. Loose connections and CVT1. Also check the R1 resistor on the excitor board and the transformer behind CVT1 (its in the back towards the left)

 

[6869704x4]

Well, this got put on the back burner for a bit. Got a good deal on a Miller Bobcat so I haven't needed a generator, but still want to get this thing going. I read Craig A Tulls https://www.steelsoldiers.com/threads/civilizing-the-mep-002a.109940/#post-1403009 and rustystud https://www.steelsoldiers.com/threa...-and-mep-003a-generators.145635/#post-1779565 posts about cleaning up the AC cabinet to ditch the 3ph option which is exactly what I want to do. They used the SX-460 ACR but I have Triple Jims AC regulator already installed. Would like to ask Triple Jim if his AC regulator is compatible with that modification. Also, I'll be contacting him for a DCVR since mine is bad.
Edit, Has anybody ever had a bad DCVR affect the main generator output?

 

[Triple Jim]

The regulator I sent you, like the original, applies current to the control winding of CVT1 when the generator output is too high. This control current reduces CVT1's output to the diode bridge that supplies the exciter field.

The SX-460 directly supplies exciter current. The stock type regulator can't do this.

The way the original regulator works is the reason the the MEP-002A and MEP-003A, contrary to widespread belief, do not stress the regulator if you run the engine below 1800 rpm. When the engine is below speed, the generator output is low and the original type regulator REDUCES its output to CVT1 to allow CVT1 to supply full current to the field.

 

[6869704x4]

Decisions, decisions. I guess I'll mess with this thing some more and probably bug yall with some more questions.