Rebuild a generator?

handirifle · Apr 21, 2016

Just wondering out loud. A relative recently bought a used generator, for cheap, and after a bit got it running. It ran and worked for a few days then quit generating. My BIL checked the windings and they are open. I wish I could tell you the brand but do not know it. It does have a 7.5hp Tecumpseh engine that runs good, they say. Of course there is always something you can use the engine for but they were wondering if it's worth it to rebuild the generator?

Or pick up a new generating unit and connect it to the motor?

Gary Fowler · Apr 21, 2016

I think if he windings are open circuit, then part of the coil is likely burned out. I don't think you could do a rewind yourself, maybe there is a shop that could do it but likely it would cost as much as a new generator head. It might be cheaper to just buy a new (or used)generator and keep the motor for a spare.

Mendonsy · Apr 21, 2016

You can buy generator heads from places like Norther Tool, but it might take a bit of searching to find one that fits. An electric motor shop should be able to rewind it.

chim · Apr 22, 2016

Not a generator, but interesting pricing. We have a bunch of 19' electric scissor lifts at work. The hydraulics are powered from a DC motor. The lifts range from 3 to 6 years in age and repairs are increasing as they age. An equipment company replaced one of these motors and charged us around $1,100 for the motor. I almost vapor locked and searched for a replacement. I managed to get an OEM motor for $600. One of our guys said he had motors rewound at a place in town when he worked for another contractor. We took a motor to that shop and the bill was $200.

hr3 · Apr 22, 2016

Where did he meter the windings ?? Before the brushes or after,, If it's a brush type ?

Dave M7040 · Apr 29, 2016

One thing to consider when making your decision. Most generator/engine units bought as a single unit have the engine crankshaft supporting one end of the generator armature. To do this the engines have a tapered shaft which makes them almost useless for other applications.
There are a limited number of taper crankshaft adapters on ebay but find one which will fit is hard. The adapters convert the tapered crankshaft from a pater to a straigt shaft with a sleeve which sildes over the taper.
Crank Shaft Adapter Taper to 1" inch Generator Pressure Washer Engine Bushing | eBay

Buying a new generator head designed to work with the tapered engine shaft you had is also very hard.
I approached a rural motor winding place with the stator of my honda EM3500 and they would not do it. They said the ones they had done were not reliable.
Unless you are a machinist or know one it is often best to retire the unit.
Dave M7040

Sawyer Rob · Apr 29, 2016

I had a 5kw Sears generator, (made by Onan) it quit making power. I ended up having to take it to an Onan repair place as Sears wouldn't touch it, and they said there was a $60.00 charge to check it out, so I left it there.

After a time, they called me and told me it had a bad armature and as Sears didn't order ANY spare parts, there were NONE! They contacted the factory and was told that all they had was the blue prints, if I wanted an armature, they would have to make one up! The cost ?, $600.00 plus!!

I had to pay $60.00 to find that out!

SR

buickanddeere · Apr 29, 2016

Prior to Y2K small generators cost approx $1000 per KW so they were repaired . Now generators cost $100 per KW . If anything serious or $$$ goes wrong. Sell the clunker in the classified ads to some cheapskate looking for a fix it bargain and purchase a new generator .

handirifle · May 24, 2016

Thanks for the replies. After reading this and other info, he bought a new one.

PILOON · May 24, 2016

With today's labor rates more and more products are 'throw away' with electronics being the best example.
I have seen so many electrical items tossed that only needed a new plug that I wonder.
I have a pal that gets all he wants from the local recycle and I am amazed, no dumbfounded.
He and I in about 2 hours returned all sorts of tools back to life (at 0.00 $) and just last week end he ran a garage sale and made $750. selling other folks discards.
Nail guns that simply needed a new trigger (sold for $100)
Table saw that had frozen(rusted) screw adjuster,
Chop saws with broken line cords.
At least 6 corded drills, (guess most wand battery drills now)
Canoes, peddle boats etc etc (fiberglass is super easy to use for a repair), he gets easy $200 as long as no leaks but he does guarantee.

Folks simply do not know how to fix or repair any more, or simply don't care.

Just today I helped him with a Bostitch 3 1/4" coil framing nail gun. A simple trigger and 10 mins had that nail gun running like new.
Repair: $27.00 for parts , cup of coffee for me, and he'll sell for about $200.
We do this as a hobby, (he for $$ to supplement his pension) me to keep active.

We are in a disposable society! face it.