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TR4/4A Checking a generator

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eyesie

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Reading the recent musings of times gone by, before putting my generator on my non running car, I decided to get it checked. I went down to Kragens, now O'Reillys to ask them to check it. I knew I was in trouble when the guy asked "what is a generator?" After high level discussions with his Manager, he informed me that they couldn't check it for me. I asked was it that they weren't allowed to check it or that they didn't have the facilities? He told me that they put the unit on a rig, push this button, then that button & it tells us if the unit is OK, but it won't work for yours!!!

I have no idea where I'll get the vacuum tubes checked when my radio dies.:friendly_wink:
 
Even older Lucas alternators suffer the same fate. I tried several FLAPS in an effort to get one tested. They all had a drawer full of adaptors to get to the specific plug needed for a particular alternator but of course nothing to match mine. I manage to convince one guy that we could do it with a couple of jumper wires I had brought, but then the pin on his machine was too large for the small lower mounting hole on my unit.

In the end, I put it on a car and tested it myself.
 
Here is an very old school DIY:
Secure generator in a vice. Move a 12v battery nearby.
Ground (+) the field by connecting to the case.
Connect the Armeture terminal to the Battery (-)
Touch the battery ground to the case. The generator should spin steadily as a motor.
Probably more fun than useful although it will probably tell you if it's totally dead or not.
Here's from Popular Mechanics 1935:
https://books.google.bs/books?id=xd...age&q=how to bench test old generator&f=false
In the end, I'd also put it on the car and test it myself.
Tom
 
That's for an American generator with the field internally connected to the armature terminal. For a Lucas generator, you should jumper the field to the armature terminal instead.

Last time I tried it, it ran as a motor, but still wouldn't generate.
 
In fact this can happen unintentionally.

I had the red light on the dash stay on after I had switched everything off. What had happened was the points in the control box got stuck together and when I looked under the bonnet the generator was trying mightily to turn the engine.

Good thing I keep the belt a bit loose.
 
Geo Hahn said:
In fact this can happen unintentionally.

I had the red light on the dash stay on after I had switched everything off. What had happened was the points in the control box got stuck together and when I looked under the bonnet the generator was trying mightily to turn the engine.

Good thing I keep the belt a bit loose.
Click to expand...

Should have just called it a Hybrid!
 
OK, interesting. after all that, I guess I'm off to Auto Exchange & see what they say.

Thamks
 
TR3driver said:
For a Lucas generator, you should jumper the field to the armature terminal instead.

Last time I tried it, it ran as a motor, but still wouldn't generate.
Click to expand...

Still, the test is not without some value. I've tried that test on several generators, and some fail it. If the generator does not spin as a motor by itself, and run smooth, it also will not generate. It is a simple test that can be done with a set of jumper cables while the generator is lying on the ground held by a foot. If it fails, it's definitely not good and will also not work on the car. The Lucas handbook describes other tests as well, but the 'motor test' is an easy place to start. Sometimes you might be able to discern why it fails the 'motor test', rectify it until it passes that test, and have a working generator. -I know that the term rectify is typical for alternators not generators, generally, but semantics can be funny. :smile:
 
It is a simple test that can be done with a set of jumper cables while the generator is lying on the ground held by a foot. If it fails, it's definitely not good and will also not work --:iagree:
 
Randall
Went to AES, they checked it, found it was charging, but mentioned it felt like a bearing was going bad. I asked how much to replace, & they said "do you want to just buy the bearing & replace it yourself". I had the test, bought the bearing, & was out of there in less than 5minutes. Excellent service, thanks for the heads up.
Are you in San Diego?
 
eyesie said:
Randall
Went to AES, they checked it, found it was charging, but mentioned it felt like a bearing was going bad. I asked how much to replace, & they said "do you want to just buy the bearing & replace it yourself". I had the test, bought the bearing, & was out of there in less than 5minutes. Excellent service, thanks for the heads up.
Are you in San Diego?
Click to expand...
Nope, I'm closer to Long Beach. Just picked their name off of Google, as they looked like the right sort of shop. Glad to hear it worked out.
 
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