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Author Topic: Help with 41.25 KVA Lister generator  (Read 1190 times)

dgordillo66

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Help with 41.25 KVA Lister generator
« on: December 21, 2021, 10:34:52 PM »
Hi everyone,

About a year ago I found this awesome looking generator for sale, I've spent the better part of the year rebuilding the engine and now that I have that ready and running I'm moving to the Generator Head, the problem is that I haven't been able to find any information or manual for it.

I does produce voltage and rated output power however I would like to use it as my home's backup generator, which means I need to dial the voltage down.
It's currently producing 341V from L1 to L2 and same from L2 to L3.

The attached pictures are from the labels and the top where I think the adjustments need to be made, I would appreciate any info or tips you guys may have for this type of head.

oldgoat

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Re: Help with 41.25 KVA Lister generator
« Reply #1 on: December 22, 2021, 11:36:41 AM »
Probably the first thing to do is throw away the selenium rectifier and replace it with a modern silicon one. Because it will fail, you just don't know when.

dgordillo66

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Re: Help with 41.25 KVA Lister generator
« Reply #2 on: December 22, 2021, 02:52:14 PM »
Thank you oldgoat, I'll start there!

BruceM

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Re: Help with 41.25 KVA Lister generator
« Reply #3 on: December 22, 2021, 04:59:11 PM »


The rectifier is not likely at fault for your immediate problem but I agree with oldgoat on replacing it for preventative maintenance.  Make sure the new one gets a good heatsink- one way or another.

If you're able to find a wiring diagram for this it would help greatly in solving your over-voltage issue but there's no harm done by trying a modest change to the adjustable resistor.  Normally, I'd suspect something has failed when output voltage is so far off. 

I'd probe the voltages (AC, DC) at that big adjustable resistor tap, move it slightly, measure again and check the output voltage again. Moving the tap away from the hot end should reduce your output voltage, as an educated guess that this resistor is in the excitation circuit path.

Best Wishes,
Bruce


mihit

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Re: Help with 41.25 KVA Lister generator
« Reply #4 on: December 29, 2021, 05:38:53 AM »
Would have to load it to see if the voltage comes down... otherwise adjust by resistor as mentioned above.

BruceM

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Re: Help with 41.25 KVA Lister generator
« Reply #5 on: December 29, 2021, 06:03:04 AM »
Good point, Mihit, he didn't mention any load and I missed that. 

oldgoat

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Re: Help with 41.25 KVA Lister generator
« Reply #6 on: December 29, 2021, 11:39:51 AM »
If this is the type of generator I think it is rotating the brush plate will change the no load voltage. Adjusting the resistor tap alters the load voltage.