Powermaster Alternator Problem

[91A-77B]

Installed brand new alternator, used 12 gauge wiring, internal ballast coil. Alt is putting out 15.5 volts, and has fried my coil. S/B max 12V output. Don't want to go thru sending my unit back, waiting for a new one. Alt grounded to block, block to chassis, body to block. Can you help? Thanks.

[hueyhoolihan]

AFAIK, most 12v batteries need about 14v to charge (charging voltage must be about 15% higher than nominal battery voltage in order to charge a battery). meaning the voltage regulator must allow that much voltage to pass through to the battery in order to charge it. that means a multimeter should show around 14v when connected to the battery terminals when the engine is running.

if it's putting out over 15v i would suspect the voltage regulator. and some alternators have the voltage regulator built into the alternator, others require a stand alone voltage regulator. either way, i would be very concerned if the battery was receiving 15+ volts.

[Ken/Alabama]

Originally Posted by 91A-77B

Installed brand new alternator, used 12 gauge wiring, internal ballast coil. Alt is putting out 15.5 volts, and has fried my coil. S/B max 12V output. Don't want to go thru sending my unit back, waiting for a new one. Alt grounded to block, block to chassis, body to block. Can you help? Thanks.

The title of your post says it all. If you’re wanting an alternator just get a GM one wire and be done with it.

[big job]

I agree with Ken = Powermaster for my 46 puts out 6.1 amps and less under load. I called them and said it may have defective regulator should I replace it. I already can tell the tone of his voice that : I : can not take it apart we have special tools for that.
That comment already tells me when this kid was born. He tells me send it back to Speedway then they send it to Us. thats BS. I have a new one on a fresh 8BA so took both mount frames and swapped them (for 1949 to a 59A) What special tools? In closing call, I told him we have repairing alternators before your father was born back in the 6volt days common on fire trucks buses etc. good day sir........

[Drbrown]

15.5 volts toooo much. Diodes in the Alternator controll voltage output. An Alternator in a 12 volt system should not exceed 14.5 volts output or ignition parts may be damaged, especially electronic ignition modules. Even a slight spike above that can fry an electronic ignition module, as I found out in a very expensive way. I learned to have new/rebuilt alternators tested at a local electric shop before installing them .... a number failed. My car came with a 55 amp GM one-wire alternator and I later replaced it with a 95 AMP due to installation of an electric radiator fan.

[itslow]

Sponsored Links (Register now to hide all advertisements)

Have you contacted Powermaster technical support? That should be your first stop.

[91A-77B]

Pleasantly surprised with latest call to Powermaster. They previously claimed problem was installation using too light gauge ground wiring or improper grounding. This time, they've offered to repair for cost of parts only; no labor or tax. So far, so good. I'll report progress. Thanks for everyone's input.

[40cpe]

They want YOU to pay for parts to repair THEIR new alternator? I would put that money toward a 10 SI from a parts store.

Years ago I bought a chrome Powermaster alternator from them in the swap meet area at the Knoxville Nats South. Installed it when I got home and it lasted a short while till the front bearing went out. I replaced the bearing and it went out shortly. I put it back in the box and took it back to them at the next Nats South. I explained to them explicitly the problem. They took it to repair and sent it back to me. I reinstalled it and it went out again shortly. I vowed NEVER AGAIN, and haven't

[Gene1949]

Never understood the PowerMaster thing unless the other people are stuck on the “cool factor”. If they are stuck “looking cool” a 12v generator and regulator (mid-50s Ford) would suffice and are readily available. UNFORTUNATELY, aftermarket electronic Ignitions don’t like voltage spikes from a generator.
I had a 10SI wired correctly with the sensing wire and it was very satisfactory with my electronic ignition.
I decided to upgrade to an electric fan and an 800-Watt stereo (why buy hearing aids for thousands of dollars when for a couple of $100 worth of amplifiers and speakers). With the 10 SI, I was running a deficit.
Anyway, I fabricated another bracket for a late model Ford alt. More compact with a lot more output especially wired correctly with the sensing wire and an inconspicuous idiot light... Coupled with the smallest diameter pulley I could find. Our motors don't turn much RPM, and the smaller diameter pulley gets the charging RPM down to about 1000 RPM which is very livable.

[91A-77B]

As promised, an update on my experience with Powermaster. I returned the alternator, and within a week of sending it, John (who I assume is the manager/owner) phoned to tell me it looks like a loose belt was the culprit. He tells me belt slipping, then catching spikes the output. Since the offset bracket on my 59A with blower makes tightening the belt difficult, and I was guilty of using the old days 3/4" flex rule. Belt has to be VERY tight. So, in summary, same-day turnaround, new pulley (old one had signs of slipping) and a personal call from the Boss! Pretty good customer service, I'd say. The old expression, the proof of the pudding is in the eating, will be tested when I re-install with TIGHT belt, and a fresh coil. I'll keep you posted. So far, 10 out of 10 for Powermaster!

[91A-77B]

.......and no charge for parts/service/return shipping.

[wga]

91A - thanks for taking the time to bring your problem to a close. Not many on this site do that, just the usual 'I have a problem' and rarely a response as to how all the advice helped or not helped.
Recently installed a Powermaster on my 49, as the EJ Whitney unit I had for 16 years
had quit. The installation instructions to tighten the drive belt TIGHT surprised me. I did as the instructions said, and no problems with my ignition or other components.
My coil is a Bosch blue, Mallory dual point (set up my our old friend Bubba)

[cas3]

WGA, When I bought my Whitney alternator years ago, I asked them if the inside components were common parts that a repair shop could identify and repair it and they said yes. Mine is still working fine, but you should have yours looked at before considering it dead.

[91A-77B]

One further bit of advice from Powermaster....cabling must be 8 gauge. A surprise, as I was using 12. Pays to read the instructions.

[fortyonerag]

The power master unit should have come with a small certificate/card saying what voltage the regulator was set to in testing. Be worth comparing what voltage you are reading to the test card.