MEP-803A - Quad fuse blows when increase of Voltage

[Guyfang]

This probably doesn't have anything to do with your problem. But someone has been in the set and "fixed" things. All the blue wire connectors are not standard. And the crimping tool was mal-adjusted, or they used that cheapo crimping tool you get for $2.99 at K-Mart. That kind of thing makes me check wires, against the schematics. Way too much pressure on the crimps. It has pinched the plastic clear through to the metal.

On the positive side, the ever elusive K1 safety cover is there! A rare bird.

And you remember what I said about marking wires? your A1 has that. I assume from you. Keep in mind, that if someone else wired it wrong, you only repeat his mistake. Been there, and done that.

Something else I just noticed. One of the "fixed" wires, TB4, terminal 2, wire # 003C. That wire goes to P6/J6 terminal #15. From there it goes to TB5-5, wire# 00S. From there it goes to several palaces, but one place is your A1, pins 4. Kind of a coincidence. I hate coincidences. If this gen set were mine. I would unhook every wire in it, and re hook them up by the schematic. Why? because the set, according to you, starts, and produces voltage. It only shuts down when you raise voltage with the R1, (something you might just test also). That does not sound like a stator failure to me.

 

[Raphael]

Thank you Guyfang - I got your point. It was before your post. The TB3 wires you see disconnected without sticker... I'm learning...

 

[Raphael]

I think I have to look into this and check the connections with the schematics. Just to be on the same page - The schematics I have are the files: 5&10kw Colored DC Sch and 10KW TQG Schematics (TM 9-6115-642-24). Is there anything else?

Do you think it is enough to measure the resistance of the cables to the other endpoint, or do I have to compare the numbers on the cables? Sometimes they are in the wire harness and hard to find.

 

[Light in the Dark]

Plan on snipping zip ties during this exercise, to see the wire ID info. Its printed every 2-3".

 

[Guyfang]

I think I have to look into this and check the connections with the schematics. Just to be on the same page - The schematics I have are the files: 5&10kw Colored DC Sch and 10KW TQG Schematics (TM 9-6115-642-24). Is there anything else?

Do you think it is enough to measure the resistance of the cables to the other endpoint, or do I have to compare the numbers on the cables? Sometimes they are in the wire harness and hard to find.

If I have the thing taken apart, and have worry's that wires are wrong, then I try and disconnect both ends, and test that wire. Mostly you can see the number on the ends. And if you are going to cut the wire ties, put new ties on the wire harness BEFORE you start cutting. Leave them loose. Then when you are done, simply pull them tight. You have everything you need for schematics. And if you can not manage to read something because the quality of the schematics suck, let me know. We are working something up to replace the old schematics. Its still a work in progress, but I think we can get you on the right track. Take your time. Use a small, but good flashlight. A dental mirror is kinda nice also. You don't need it, but when you do this sort of thing every day, its handy. Works best with someone helping. You look, they read off the schematic. Also look for wire connectors that are loose, or maybe the strands in the crimp area are broken. If the end flops around, aint no good. Check for tightness. And all those blue terminals are the wrong size. I would replace them, and use a good crimping tool, not some $2.33 job. look for overheated wires. If the wire is brown/black, and feels bubbly, check it out extra. As long as you are in there, pull the S8 out and try and blow out, clean out, spray with Detox, or what ever its called. From the pictures, there is mucho dirt/sand/dust in the set.

 

[Raphael]

It works!!! OK here is what happened. Actually nothing was wrong, only the generator speed was way too low -around 45Hz. I was not aware, that this could cause the fuse to blow. I was so focused on the fuse blowing and something being wrong, that I didn't check that.

I really thank all who were helping. We learned a lot about this generator. It's a nice piece of equipment and I apologize for not finding that earlier. Maybe this may help another generator-Greenhorn

Especially Guyfang's hints were great! If I were in Burgkunstadt, I would invite you for a beer - there are great breweries in your area!

 

[DieselAddict]

Great job. Thanks for closing the loop on the problem!

 

[Guyfang]

It works!!! OK here is what happened. Actually nothing was wrong, only the generator speed was way too low -around 45Hz. I was not aware, that this could cause the fuse to blow. I was so focused on the fuse blowing and something being wrong, that I didn't check that.

I really thank all who were helping. We learned a lot about this generator. It's a nice piece of equipment and I apologize for not finding that earlier. Maybe this may help another generator-Greenhorn

Especially Guyfang's hints were great! If I were in Burgkunstadt, I would invite you for a beer - there are great breweries in your area!

Glad it works. I didn't think it sounded like the stater or winding was bad. Not when the main gen would come up, make voltage at first.

Chris, What you think? The freq is low, the VR is trying to compensate by boosting the AC voltage? I wish I had a set here, I would turn down the freq to 45 hertz, and see if I could blow the fuse.

Raphael, I would show you the best breweries in the world, within 40 min. of the barn here!

 

[DieselAddict]

For sure if the RPM is low the VR is going to have to work harder to get the voltage up in stator. That absolutely could blow the fuse on high current. Its a good thing the fuse was there otherwise the exciter would have been toast for real!