generator test

[gregy]

Does anybody know a simple way to test a generator while on the tractor. Just to tell if it"s working or not ? 1948 8n

 

[Bob]

Check it's output voltage with an ANALOG voltmeter.
(It's NOT uncommon for a digital meter to throw a hissy fit and give weird readings 'cause of electrical "noise' generated by the ignition and charging system on these old beasts.)

It needs to be putting out about 7.4 Volts to fully charge the battery.

 

[Leemo]

Take the belt off and disconnect the wires then use jumper cables to connect it to the battery and see if it motors.

 

[gregy]

Do you hook it to the armature and ground?

 

[Bob]

Yes. Between the output stud ("armature") and ground.

 

[JMOR]

(quoted from post at 12:46:04 11/06/08) Check it's output voltage with an ANALOG voltmeter.
(It's NOT uncommon for a digital meter to throw a hissy fit and give weird readings 'cause of electrical "noise' generated by the ignition and charging system on these old beasts.)

It needs to be putting out about 7.4 Volts to fully charge the battery.

Maybe a couple more for him, Bob.
http://ytforums.ytmag.com/viewtopic.php?t=391797 :wink:

 

[gregy]

Leemo, with your method, do you hook the hot lead to the field or armature?

 

[Leemo]

I didn't remember so I borrowed a post by JMOR.
If nobody changed it over the last 50 odd years??.......then it probably has the externally grounded field, also known as type A, also known as internally supplied field. On these, to motor them, ground the Field to case and connect battery to ARM (also known as GEN) terminal. Use same polarity as it sees installed on tractor. That is if tractor is POS GND battery, then connect NEG to ARM/GEN.

If it happens to be a type B, aka internally grounded field, aka externally supplied field, then procedure is different. For type B, tie BATT to BOTH the ARM/GEN and the Field and case to tractor frame.

 

[gregy]

I just went out and tested it. Neither test indicated it was working.

 

[JMOR]

Earlier, you said, " The gen was checked out and it works."
If that was at a generator shop, I would return and ask for a repeat test.

 

[souNdguy]

If an a-circuit won't motor with the belt slipped off and the arm hooked to bat hot and the field grounded.. then it needs attention.. might be shot brushes.. bad field.. or bad armature / open.. etc.

soundguy

 

[gregy]

Yes, that was at the ele. shop. I think I'll go to a different shop.

 

[Anonymous-0]

I got a real easy one..... Loosen the ground cable on the battery so it can be lifted off fairly easy BUT leave it on the post for now. Start the tractor (that is the reason for leaving the cable on the battery post). Now with the engine running at an idle, slip the cable off, away from the post. If the engine stays running your genny is good..... good enough to power the ignition any way. Some guys will disagree with this method, but I've done it alot and have had no problems doing it.

 

[Anonymous-0]

3 brush generators will run up to 18 volts with no battery load.Shunt coil in the cutout will over heat and burn ,Ignition coil will do the same.If a battery cable gets loose on a car at night the lights will burn out, gauges and sending units will burn out.Use this method on your tractor but dont recommend it to others.

 

[gregy]

Lumpy, I just tried your method the motor died immediatly. Using the other methods stated on this board I'm sure I've got a bad generator.

 

[jon]

Lumpy, I just tried your method the motor died immediatly. Using the other methods stated on this board I'm sure I've got a bad generator.

I thought the same thing Greg but turned out to be the Voltage Regulator. $26 fixed it.

 

[GB in MT.]

[b:eab5a0520e][i:eab5a0520e]

jon..........you got gobs of email

Gary [/i:eab5a0520e][/b:eab5a0520e]