How do I test my 6v Generator?

Tomorrow...will try to find old time test procedures for fields and armature, and cover:

Building test devices capable of killing you!
Mining for smoke!
Using your telephone to replace the smoldering ruins with a Chinese alternator!

 

Bruce, I got a nice old growler, I know you know.

 

Wow! Can't wait for tomorrow's installment!

 

GP, can you do a post on here on the growler?? Never had one, my stuff is continuity/insulation testing

 

Oh, GP, that's me? Did I have my hand up?

I used this very rarely, cause most of the time, you know when the unit came off, what was wrong, or the failure is obvious. Sometimes you get a unit that doesn't seem to have a reson for failure, then you need to look harder. This is what a growler is for. You already checked the armature for grounding, from each commutator bar to the shaft, that was OK, now you use the growler to check for shorts betrween the coils. and I also think open coils.
From wikapedia, because they can explain it and I type with two fingers, sometimes three.

Growler (electrical device)

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<!-- start content -->A growler is an electrical device used for testing insulation of a motor for shorted coils. A growler consists of a coil of wire wrapped around an iron core and connected to a source of AC current. When placed on the stator core of a motor the growler acts as the primary of a transformer and the stator coils act as the secondary. A "feeler", a thin strip of steel (hacksaw blade) can be used as the short detector.
The alternating magnetic flux set up by the growler passes through the window of the armature coil, generating an alternating voltage in the coil. If the coil is shorted, an alternating current induced in the coil will cause an alternating magnetic field to encircle the shorted conductors.
With the growler energized, the feeler is moved from slot to slot. When the feeler is moved over a slot containing the shorted coil, the alternating magnetic field will alternately attract and release the feeler, causing it to vibrate in synchronism with the alternating current. A strong vibration of the feeler accompanied by a growling noise indicated that the coil is shorted.

Along with the standard application the growler can be used to:

• test series and interpoles (commutating) fields from a DC motor
• to determine phasing and polarity in multiwinding armatures
• to test rotors in rotating frequency changers, as well as in wound rotors
• to test shorts between turns in taped coils before installation into an armature or a stator
• as a low voltage isolation transformer
• as a high voltage auto-transformer bucking or boosting for numerous tests on various types of equipment
• for preheating or baking armatures and rotors.

It is considered by many to be one of the most versatile tools for electric motor service.


Here's a picture, maybe you've seen one and wondered what the hell it was?

 

Will post test stuff tomorrow...too much happening today. Blasted reality nonsense...

 

Thanks for the info GP. I stopped by the electrical shop today while I was out and about. All signs are pointing to regulator failure for me. I have one on order, I'll let you know how it turns out.

 

Use the full-fielding test, post 23 above...should kick gen to full output if reg is the problem.

 

Even on a Chevy?

 

A CHEVY?? Will look that up.

 

Jumper from field on reg to a ground full-fields a Chevy. Formal test would put voltmeter between armature and ground, field expedient is watch headlight brightness as voltage goes up.

 

Changed the regulator, no dice. Took it to the shop that rebuilt the generator, loose brush. Back in business

All good advice none the less, will file for future reference (hopefully NEVER! )

 

Very good thead, I have been having this problem with my car for some time and have a few more questions.

What about the earlier ford gens. like 35-36 ish (the ones with the cut out on top), I am running this stye, and I have hooked it up to a charger and it works as a motor but I can't seem to get it to put any voltage out? There are just two wires coming out of the gen. I assume one is a grond and the other one goes to the cut out?

I have hooked a volt meter between the two wires and spun it with a drill, it reads like .15v which is something but I would think it shoud put out 6 or more volts when doing this? I'm running 6v pos. ground. I have a new cut out, the one with a diode.

 

More testing on innards coming, still don't have enough typing time.
Your '36 takes a cut out up top...from memory, one wire gets grounded to cutout screw, other goes to cutout, then wire from other side of cutout to battery and car...
I think gen will put out without the cutout, but will drain the battery (I think trying to motor??) when car shuts off...cutout just disengages gen when it is not producing.

 

Bruce, it is the type with a cut out on top, two wires come out of the gen. when I test across the two wires with a volt meter, I get less then a volt comming out.

It seems like I should be seeing at least 6v.?

I'd like to get this thing fixed so I don't have to worry about how far I can go.

Thanks for the help, might have to take it to a electrical service shop.

 

ground the one wire to the case, I think. Not very familiar with these.

 

Here are the Neat-O tests that can kill you! I'll post some non-lethal tests using a meter later.

Generator parts testing, 1953 style

Here are a series of tests for generator components from the Ford of Canada &#8220;Master Repair Manual&#8221; from 1953. They specifically apply to &#8217;49-53 vehicles, but I believe I am correct in saying that procedures apply back to the introduction of the 2-brush generator in 1937-8. The only circuitry difference is that the first couple of years lacked a proper ground wire, grounding only through their mountings.

Most of these tests involve 110 volt household electricity, presumably to force breakdown of any marginal 6 volt hardware. I am sure you are aware that this has potential danger if carelessly handled.
There are many ways to test generators without this&#8230;I will post a link to some simple tests, and many of the tests can also be done using multimeters, as detailed in a number of Ford USA books. The 110 system has the advantage of testing the breakdown points under more stress than they will see in actual service.

Equipment: The basic tester is simply a 110 volt bulb in a porcelain socket (let&#8217;s try to be traditional here!) fitted with test prods; One wire goes from plug right into fixture, as normal, the other wire is terminated with a sharp steel prod, and the empty terminal in the fixture is fitted with another length of wire also with a prod or, possibly better, a big alligator clip. When the two prods meet, either directly or through a conductive path in your generator, the bulb will light. I&#8217;ll leave the fabrication of prods and insulated grips for them up to you. This stuff was standard in auto electric shops long ago before electronics made such testing obsolete.

I believe choice of one of the plug poles will be marginally safer than the other, and I think I know which, but I haven&#8217;t finished contemplating that and I hope someone with a sharper knowledge of 110 will step in and clarify that for me.

Next, I will paraphrase Quin the Eskimo, your Ford of Canada service rep, testing the components of a disassembled generator for electrical integrity:

The series begins with a growler test. I have no growler and can&#8217;t help you there&#8230;

Next, clamp the wire from light fixture to the armature shaft rear bearing area. Jab each segment of the armature with the prod from the wall socket. If the lamp lights during this, a segment is grounded and your armature has failed its final.
Parenthetically, I understand that electricity flowing from one hand to the other in the case of your accidentally including yourself in the circuit is highly dangerous, as the electrical path goes right across your heart. Set up your test so that the parts are stable, hold your prod in one hand, keep the other hand in your pocket&#8230;that technique is used by many electricians when fiddling with live 110 for safety.

Onward&#8230;to the endplate. Clamp wire to endplate casting, prod the ungrounded brush holder. Darkness is good&#8230;

Field coil windings are tested still assembled in frame, unless trouble forces disassembly. Clamp wire to frame/body of generator, prod the field terminal. If lamp lights, field is grounded and that is not good. Field resistance is checked with a charged 6V battery, hooked with one terminal to field stud with an ammeter in circuit, other to ground stud. I do not have figures for 12V generators, but at 6V resistance should be 1 &#189;--2 &#189; amps. High means shorts between windings, very low or no reading means open circuit.

This battery and ammeter circuit can be used again at the end of your rebuild for a final bench test of the complete unit: Place a jumper wire between field and armature terminals, run ammeter lead to ground post, other to armature. Generator should run as a motor and draw somewhere about 5 amps.
I hope I got all that right&#8230;will try to get multimeter type test procedures together soon.
I&#8217;ve never done this with 110&#8230;I&#8217;ve only done continuity lamp checks with battery voltage myself. I believe the low voltage tests will show parts to be currently usable while the 110 tests will expose functional-but-weak parts that are likely to fail in the future.

I&#8217;ve rebuilt a bunch of generators that were functional units when I started, but I&#8217;ve never encountered any of the serious problems that can occur on elderly windings. If I have something above wrong, please correct me on this! I know there are people here with much more generator experience than I have.

2 links to Ford generator discussions:

Polarizing your charging system is covered in the first; note that there is one way for Ford systems, another way for Delco and most other systems. MANY people have the two confused. Be sure you are doing this using the Ford/heavy duty circuit system, NOT the Delco, as ground paths are different and smoke may result&#8230;
Both ways are in here:

http://www.jalopyjournal.com/forum/showthread.php?t=256038&highlight=generator+polarize&showall=1

Simple field testing with no tech:

http://www.jalopyjournal.com/forum/showthread.php?t=278956&highlight=generator+polarize&showall=1

 

While searching for something else, I ran across this older excellent thread.

Thanks Bruce and others.