View Full Version : Generator Test Bench

01-19-2008, 07:01 PM
Just wondering if anyone has ever constructed a generator test bench, either of their own design or similar to the one described in Bruce Palmer's book? Just wondered if this would be something practical to build, and how cheaply it could be done?

Mike (resident cheapskate) :D

T. Cotten
01-19-2008, 07:29 PM

The hardest element for me to scrounge was a variable speed motor with enough poop. I ended up with one off of a hospital therapy bed.

The cost of any project is relative to how much time you spend running the alleyways and diving in dumpsters.

My testbench has been through several revisions,... but I don't think I ever spent money upon it.


01-19-2008, 08:01 PM

Good to hear from someone as thrifty (my wife calls it cheap) as I am! I don't mind rummaging thru other people's unwanted treasures, just trying to come up with ideas whereas to scrounge up parts!


01-20-2008, 01:46 AM
when it comes to other people junk just remember 'it's not what it is ,it's what it could be '

01-20-2008, 10:54 AM
That sentiment has gotten me in big trouble with raggedy old piles of parts that "could" be motorcycles.

T. Cotten
01-20-2008, 11:48 AM

The most trouble I've gotten into dumpster diving was when my poorly-executed entry hit above the beerbelly, and I cracked a rib. But I still completed a proper dismount with a crate of 3" pipe bushings.

(They may not be cycle parts directly, but they serve well for press anvils and other simple tooling. On a lighter note, I pulled a full five-pound tube of Stay-Silv #15 from a tavern dumpster yesterday.)

Back to generator test stands,
my hospital bed motor is not easily reversable, so I do not test many Autolites.


01-20-2008, 12:48 PM

Do you know of any other good alternatives to the hospital bed motor? I'd look kinda silly hanging around the local hospital, and diving into the dumpster with all those used needles could be painful! :D


Perry Ruiter
01-20-2008, 02:16 PM
Here's the test bench I built with a friend. Not sure what the motor is out of. The lever sticking up out of the back is connected to the brush holder. You can vary speed (and rotation) by altering the position of the brushes. There's a headlight and taillight bulb on there so we can add some load and verify the generator works as expected. The gauges were military surplus. There's a naval base here so when they retrofit the ships this stuff comes available. I've run a lot of generators on this rig ... Perry

01-20-2008, 02:22 PM

Nice stuff Perry! Very professional looking. I imagine if I DO ever figure out how to build one, it will look more like a child put it together! :rolleyes:


Perry Ruiter
01-20-2008, 09:13 PM
Here's a more pedestrian "test bench" I picked up cheap at a swap meet a couple years ago. Constant speed. Hose to couple to the generator gear. I bought it strictly for the piston pin pusher that is used as a generator clamp. Haven't gotten around to striping it for that yet ... Perry

T. Cotten
01-20-2008, 09:30 PM

The pin-pusher is a real find!

But don't dismiss the bakelite switch... I regret cracking one of the two I use.

Meanwhile, for those of you who need to drive a generator in a hurry:
Hook it up with jumpers and hold it's gear up to a wire wheelbrush spinning about 1725 rpm. It won't give an accurate output curve, but you can quickly read a yea or nay.


01-20-2008, 09:43 PM
Page 374 of Bruce Palmers "How to restore your Harley Davidson" discusses assembling a generator test bench.

03-14-2008, 04:50 PM
attached are some pics of my self made generator test bench with a 24V truck starter. The motor has 7 KW power and is driven by 2 large 12V batteries. To control the out put I use a vintage battery tester with thick carbon discs inside. Together with the revolution counter I can adjust the current revolutions from 1000 to 5500 rpm. Ihave installed a 6V and a 12V test circuit.