Homebuilt Starter/Alternator Test Bench?

[RonRock]

I want to build myself a test machine for starters and alternators. It seems straight forward enough, but I'm sure that there are others out there that have built them, probably good ideas from their work. Not finding much from my searches other than manufactured units. Anybody have any place that I could look for ideas? Anybody already build one here?

It seems that the old guys have all passed on or retired it's hard to get anything repaired these days, always just replace with a parts store cheapo. What gets me to this is the alternator on my skidsteer. I pulled it and replaced the bearings, slip rings and voltage regulator and cleaned inside and out. I have taken it to 5 different places to get it tested, one a Case dealer. None could test it. All had a different BS reason. All wanted to sell me a new alternator. These are all places that I buy parts from often, except one that my Case dealer sent me to. They seemed like they might have tested it, but had sold their test machine a couple years ago.

Not easy to pull from the skidloader, have to pull the radiator to get to it.

 

[Stuart in MN]

Starters, alternators and generators are generally pretty easy and inexpensive to rebuild with new bearings, brushes, etc. - more people should do it instead of just throwing them away.

A search for "homebuilt alternator test bench" turned up several options on YouTube - basically, you need a way to spin it with an electric motor or even a hand drill.

 

[PoorUB]

Hand drill? You can get an idea if it is charging with a hand drill, but a drll will not have enough power to get a decent load test. With many of todays alternators running 150 amps or more you need a pretty decent electric motor to spin one up, probably 2 HP. You could get by with less, but you would not be able to test them to full output. Then you need a load bank and a battery. You could use a carbon pile battery tester as a load bank.

Starters are about impossible to bench test. You can clamp one in a vise and hook a battery to it and see if it spins, but to test it under load would be difficult.

 

[FredWanaker]

A friend has one. He welded up a frame that he could clamp down or bolt up an alternator, then he has an electric motor to spin it - chooses pulley size to get the right RPM range, and uses an electric motor speed control to spin at different speeds. He has jumpers made in case the alternator uses an external voltage regulator. Uses a VOM to check for voltage, and an oscilloscope to look for ripple. Alternators need a battery to excite them, generators do not. As to starter motors, some use bushings in the bell housing to hold the nose so depending on the starter you may need to have a bunch of used bell housings sitting around. Part of it is making sure the starter gear either spins out or the fork pushes it out. I've rebuilt many alternators and generators over the years. One thing is to diagnosis the issue before you tear into it. If it has a burnt smell, or has thrown solder etc., go get another core. Generator armatures can be growled to see if they are shorted. Each type unit you test will have a different mount, and procedure so there is a big difference between building a test stand for ALL generators and alternators VS just specific models.

here is a link to public photos of his test stand

https://www.thesamba.com/vw/gallery/pix/1816952.jpg

https://www.thesamba.com/vw/gallery/pix/1816953.jpg

https://www.thesamba.com/vw/gallery/pix/1773468.jpg

https://www.thesamba.com/vw/gallery/pix/1773469.jpg

https://www.thesamba.com/vw/gallery/pix/1772930.jpg

 

[wssix99]

Look for Alternatorman on youtube. His videos will show you the way.

 

[nadogail]

In my local area automotive parts stores offer to test alternators, starters and batteries for free. Obviously their intention is to sell you a new or "Rebuilt" unit after they ave condemned yours; very simulator to brake shops offering "Free" brake inspections or tire shops offering to fix your flats for free.

If you know their game, you can play with an advantage.

 

[unslow1]

I've never heard of a place that fixes flats for free. They are expensive around here. Would getting a parts store tester cover those tractor starters and alternators?

 

[nadogail]

When I was working in San Diego as the only maintenance tech for an industrial plant I took the tires from the Boom Lift to 4 Day Tire.

I would not advertise that the Alternator or Starter came off a tractor. Alternators and starters are pretty much common items. "Can you PLEASE test my alternator and see if it is keeping my battery from charging?"

"Oh I need a new one? Thanks, I will have to wait until after Pay Day"

 

[lilredex]

I made a simple plug in box that contains the Mopar charging circuit of the seventies/eighties, just add a battery. The slide in bracket clamps to the rear of my table saw, plug in the alternator, and drive with the TS motor. The test box can be used on or off the vehicle.

Got the idea from a junk yard with a similar setup.

 

[The Cobbler]

I worked in a starter /alternator rebuild shop, the load test for starters was a 2x4 wedged in to the drive to create load.

 

[TractorJeff]

Could not take the CAT Alternator from a Track Loader to Orielly's or Autozone for a "FREE" test! Their computer automated machine needs a Code typed in to program/test from. Plus the machine tells the operator what pigtails to use.
Word of Warning on these!
Don't use cheap Aftermarket Regulators in them as they will drain the Battery over a couple of days time! Customer bought a cheap rebuilt for me to install. Over 2 years time, I replaced that Alternator twice. He insisted that the Supplier was selling him Bad Alternators, Supplier would test them stating they are fine. Finally he knuckled under and bought one from CAT. Never had a problem after that!
Had the same problem with an old Delco SI from a Case skidsteer, I guessed a wrong vehicle application (GM Truck early 80's vintage) which they looked up and were NOT smart enough to figure why it didn't work? I finally got them to look up the Manufacturers Code on the Alternator to get the correct Code for the Tester Computer to program itself.

 

[RonRock]

Thanks guys, that gives me some places to look for ideas.

 

[goingtoarizona]

Back in the dark ages, we used a two by four against the starter drive on our test bench at the parts store. This tests to see if the starter drive is worn out..