Any generator experts in the house?

[cheese1566]

I bought a used Powermate 3000 watt generator for only $25 yesterday. It only has 25 hours on it. The man I bought it from said he was using it camping and it just stopped producing electricity. The motor is great and starts for me on the first pull. I figured I would chance it as I love to tinker, gets me in the garage to hide, and if nothing else, it wasn't that much $$. I has hoping for a simple fix....

i tried Google and attempted the generator fixes by spinning a drill and also connecting a battery to the brushes to excite the field. No luck. It didn't even arc when I touched my good 12 v battery to it. (It wasn't in storage and not used so I didn't think it was a loss of magnetism over time as it stopped producing while the gas engine was running...)

i found with the motor running, I am getting about 0.9 DC volts across the connections of the brushes with the wires removed. With it not running, nothing. (End of the generator with the end cover off.)

I tried a digital multi tester at the brush connections as well with the wires removed to test continuity. It is showing "1" on the digital read out for the 20,000 ohms setting. The brushes show something and pass current. With the brushes removed, the tester directly on the armature where the brushes contact read "1" as well.


Looking at the windings, they look ok and nothing on the sniff test of a burn smell.

I am thinking the the armature has a fault. I don't think it is shorted as I would see something in the tester, but maybe a break as the tester is reading 1.


I see eBay has replacement voltage regulators for $17. I would get one, but wondering if the armature is bad. Be an easy fix for $17 if it may do the trick.

[too many things]

if it was hooked up and the power came back on while it was running it would most likely take out the regulator first. would look and see if the wiring around it is burnt
it could have a reset and it could have burnt also .
most of those resets are sealed so would be hard to tell unless you have the test method . and then it may not work if it was "welded" inside
one thing is to check the brushes and see if the spring is burnt

[lancem]

Regulators are what usually go in my experience.

[Petrol & Powder]

I agree on replacing the regulator. With no obvious fault in the brushes or windings, the regulator is the next logical place to fail and the replacement part doesn't cost much to test that theory.

[Mytmousemalibu]

Could take the armature to a shop that has an old armature growler. Someplace like a electric motor shop, starter & alternator place maybe.

[cheese1566]

I wasn't sure if I was getting the correct readings to indicate if the armature was ok. I cannot find any good resources for this model to troubleshoot.
I did order a cheap voltage regulator for $16 on eBay to try. I may email the company but unsure if they give that type of info.

[ozarkhillbilly49]

cheese ohm between the slip rings. should show a few ohms. next check from silp rings to ground. should show high ohms. next locate the field winding leads. should b 2 leads per winding. all field coils should ohm a few ohms lead to lead. again check coils to ground. should ohm hi. if all windings check out the next thing to look at is the exciter recitifer. proabaly a bridge type. ac goes in on 2 connections and dc out on 2 connections. put 110 volt ac in on the ac conections and check for dc out on the other 2. if no dc out replace the bridge. mpja has em cheap. go for about a 500 volt bridge at 50 amps.anything over a 100 volt will b ok.hope this helps. pm me if you need anything else.

[Plate plinker]

Voltage regulator is very common.

[cheese1566]

I guess I should clarify that the reading of "1" on my digital meter looks it no current is passing through the armature when try the ohm meter. It's like I ain't applying anything at the brush terminals. Makes me think it's a broken connection. When tried exciting the field, I didn't even get an arc or spark with my good 12v truck battery.

i did try testing at the split rings and doesnt show any ohms or a low reading. Haven't gone out to try the leads or rectifier yet.

See what the new voltage regulator does when it comes in. It will be easy to connect. If it doesn't go with that, I will dig deeper.

[Alstep]

A while back, I had a generator that didn't generate. Lost it's magnetism just sitting around. Plugged in a power cord, stripped the leads on the other end, and while running, touched them to a 12 volt battery. Just a quick touch is all. That's all it took to get it to generate again. Give it a try, nothing to loose.

[cheese1566]

I did using a car battery over the brush terminals. Also tried the drill method with a drill and a hand grinder.
Didnt try it with a cord going through the outlet. Maybe I'll give it shot tomorrow night.

[ozarkhillbilly49]

cheese sounds like you got a open armature there.

[cheese1566]

Got it!!
As we concluded, it was the armature. I tore it down and found one broken wire at a split ring where the brushes contact. Bared the the wire and soldered the best I could. Then epoxied the connections for reinforcement. It took 3 hours tonight from start to finish. Quick test and she is outputting.
Guess I didn't need that voltage regulator from eBay after all, but I guess for $16 it will be a spare for the future.

179088

[SSGOldfart]

My small 900w won't put out voltage if there is a over load or no load,I unplugged,my coffee pot,and plugged in a small battery charger,and it reset on its own!!! So I guess it has a sealed reset some where good luck,and remember to ground it.
Be safe

[Plate plinker]

well thats a darn cheap generator. Well done.

[osteodoc08]

$25 generator. Winters coming. Knowledge gained. Win win win. Great job!