Did I blow this alternator?

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Model T Ford Forum: Forum 2014: Did I blow this alternator?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Bruce Stafford on Saturday, January 04, 2014 - 05:57 pm:

Finally got the steering done and roughly timed so decided to fire up the old '26 Tudor today. Put the custom covered drivers seat in and fired it up and limped around the neighborhood. THe Herman Campbell rebuilt engine needs for me to get the timing straightened out, however. I WIred it up using an old wiring diagram with appropriate modifications. Wired the alternator up to the the battery as shown. When I got back to the house I noticed when I turned the ignition switch off the amp meter was pegging about 30 amps with the engine not running. Got out and unhooked the alternator and noticed that it was hotter than a firecracker. Figure I fried it. Any comments? I just know the amp meter should not be pegged with ignition key turned off. Unfortunately while I was driving around the neighborhood, fiddling with the pedals, and trying to keep the engine running with spark and throttle I did not look at the amp meter while driving. It is a single wire alternator and perhaps I shorted it. Who knows. The only reason I'm restoring this 26 Tudor (from the frame up) is so my son-in-law won't be tempted to turn it into a rat rod! Now I gotta figure out how to get it off the engine to get it tested and likely repaired. I've got a distributor on the car so no manual for how to get it off. Further comments will be most appreciated. Does this qualify as a post or just rambling from a frustrated restorer?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Saturday, January 04, 2014 - 06:40 pm:

Bruce,

Alternators put out a set voltage to charge the battery. The amperage is whatever it is up to the rated maximum of the alternator. You could have been outputting 50 or 60 amps. The amperage number is largely unimportant so long as the wiring is capable of handling the amperage that the alternator is capable of producing.

I recommend you get a voltmeter so that you can see the voltage regulator functioning. An ammeter is not very useful with an alternator circuit. Second, be sure the wiring big enough for the one wire that goes from the alternator to the battery.

I wonder if the ammeter was fried by the excessive current and stuck in the 30 amp position.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Saturday, January 04, 2014 - 07:23 pm:

Bruce: Welcome aboard !

Good ride today.

What type and manufacture alternator do you have ?

6 or 12 volt ?

Condition and guage of wiring harness wires

The answer you received was born solely on assumptions.

You need to provide more information on your particular unit to help with the better answer.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Saturday, January 04, 2014 - 09:11 pm:

Might you have installed the battery in "backwards" with the positive post going to the frame instead of the negative post? T's were all negative ground as should be your alternator. If you installed a Model A alternator then it probably was a positive ground alternator. Just guessing. In any event the polarity of the installed battery must match the polarity of the alternator. Both must be negative ground.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Daryl W. Becker on Saturday, January 04, 2014 - 10:00 pm:

Yes something is obviously crossed or reversed, sent PM with info to contact, best to pinpoint problem instead of guessing, not sure I fully agree with the worry of alternators OVER charging the AMPS as spoke of earlier, especially with load and speed of the T, THAT is not an accurate concern, I am sure the 30 amp reading is from a SHORT not an over charging,
The alternator will NOT produce its maximum or RATED amount without a relative RPM and LOAD demand, a (short) condition does NOT make this happen , That is why a larger scale ammeter is not required when installing an alternator UNLESS additional Loads/accessories are added to the vehicle, I am sure a few easily answered questions will reveal the problem


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, January 05, 2014 - 01:22 am:

Daryl:

While I agree with most of your posting, I respectfully disagree that a larger scale ammeter is not required when using an alternator. As you know I make ammeters and they are for 20 amp systems and if the battery is low and the RPM is sufficient, an alternator can burn out our ammeters since the alternator by design will deliver whatever amps it can produce at any given RPM and at any given load condition if wired in place of the generator. An alternator is not like the adjustable 3rd brush generator which has an adjustment that limits the maximum amps that will come out of the generator regardless of any load condition or RPM. I am uncomfortable not warning my customers of this fact. They can wire the charging source so that the ammeter will not be functional to display the alternator charging current but that is not the normal wiring of the T and my experience is that most people simply wire the alternator in place of the generator and that can be a problem for any 20 amp ammeter including ours. It is ultimately up to the customer what they choose to do but it is up to us to warn folks of improper installation that can harm something.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Daryl W. Becker on Sunday, January 05, 2014 - 11:51 am:

An interesting and Accurate survey would be..., Anyone who has an alternator installed on there T, What is there amperage readings???
That will answer the question of the output,


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, January 05, 2014 - 01:39 pm:

Daryl:

No it will not answer the question I propose and a survey does not talk at all about the worst case. I am not talking about "typical" readings.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Daryl W. Becker on Sunday, January 05, 2014 - 02:16 pm:

your saying then just BECAUSE a alternator "CAN", (has the possibility) to produce more amperage, that its worth adding a larger scale ammeter , JUST IN CASE ???

instead of actual readings from people who use them every day and they do not over charge the ammeters???


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Sunday, January 05, 2014 - 02:52 pm:

I have installed a number of alternators on Model T's, both six volt and twelve volt. They are very hard on ammeters; it is normal for the ammeter to peg for a long time after starting the car.

It is important to realize that you are not seeing what you need to see with an ammeter / alternator equipped car. You need to see the voltage output so that you can tell whether the battery is being overcharged. You would never be able to tell from an ammeter. Voltage regulators can fail either overcharge or undercharge. You don't want to find this out from exploding batteries.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Sunday, January 05, 2014 - 03:13 pm:

Bruce:

You have as a newbie, been embroiled in past controversy of Generator V. Alternator. Don't let this scare you.

Mr. Regan makes a fine regulator for generators, and Mr. Becker makes a fine alternator for Model T's.

I'm interested in you answer to my previous post.

Bob Jablonski


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bruce Stafford on Sunday, January 05, 2014 - 03:58 pm:

All,
The alternator is a single wire Delco, 12 v negative ground. Don't know why I fussed about it so much. It was easy to remove. The meter was pegged at 30 AFTER the ignition was turned off. The wire from the positive pole was 12 guage and ran to a 40 amp breaker I found at NAPA. That then ran to the meter with the other side going to the hot side of the circuit. I admit I ran all my own wiring because of all the non-standard features but was following the spirit of the old wiring diagram, being careful not to ground anything that should not be grounded. There is enough of the old electrical engineer in me that I didn't do too much stupid I think. I'll take it to a local parts store and have it tested. I understand there is a local shop that can repair (likely). bottom line, I just know the amp guage should not peg with the motor not running unless I blew the alternator. Did the "hot" side of the thing get grounded to the hot engine. Who knows. I'll get it checked out tomorrow. Meanwhile look at my other post about leaning. Thanks all. BTW, how many T's does one have to restore to become an expert? I'll never know because I ain't doing this again! Oh and I am not going down the road of gen vs alt.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Sunday, January 05, 2014 - 06:05 pm:

Wiring harnesses from Sacramento Ford made with correct guage wire would help you .... extra heavy wire used for battery & gen/alt leads.

I understand wanting to get the 'ole girl running, but good wiring is needed.

Rhode Island Wiring Services, Cole Ignition, or any of our vendors can supply your needs.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bruce Stafford on Monday, January 06, 2014 - 05:34 pm:

Took alternator to local shop. I blew the regulator and diodes which means I must have shorted it. They had it fixed in about an hour. Will put back in with 8 guage wire this time. Thank goodness this was not an expensive lesson.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Monday, January 06, 2014 - 07:00 pm:

Bruce: Thanks for the update.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Monday, January 06, 2014 - 08:13 pm:

I think the 8 gauge wire was a wise move.


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