several voltage regulator burn

[madmax2]

Hello
I have burned several VR (solid state) they do not burn instantly, it takes a while. It all started when I took the engine out to make some upgrades.
When they delivered the car to me I noticed that the regulating voltage was 12.9 V, before it was more than 13V and cruising 13.7v and before 14-14.2 v
When I returned home at a traffic light I saw that the voltage had risen to 16-17v. II checked the VR and the transistor was burned, I changed it and it started working again but not with the original voltage values.
With this trial and error I have already burned 4 VR, the other times the circuit was open and the alternator did not charge, the car only ran on battery.
I checked the alternator, Powermaster 95A Mopar round back style, OK.
I checked all the grounds: Battery to the chassis, battery to the engine and a direct ground cable from the battery to the VR. Everything ok but the transistor raises temperature until it burns.
I did a transistor upgrade with a higher IC collector current, and I had time to prove that when regulating there was a drain of >30A... I changed the battery and the drain regulated lowered to 6A, regulating the voltage was 13.2v and cruising 14.0v
I thought I had found the problem and that it was the battery.
I made a 65 mile trip and everything went well, but on the way back the VR burned again.
any ideas.
my setup is a sb mopar 418ci with a Holey HP ecu with Terminator TBI, C-N-P IGN-1A coils. Powermaster 95A dual field (one field to ground)

 

[Dana67Dart]

Fyi

If you can get the transistor number you can replace it. And replace it with a higher current version.

This is my thoughts, no particular order...

1. The regulator might not be able to handle the field current the alternator is needing.
2. There might be an intermittent short in the field wire between the alternator and the regulator.
3. Perhaps there is something (electric choke?) on the field wire.

A way to test for #2 and #3 is run a dedicated wire from the VR to the field terminal on the alternator.

As for the regulator not handling the field current, turn off everything in the car, (radio, lights etc. ) remove the field terminal and run a jumper with an amp meter in series from battery to the field terminal. This will full field the alternator resulting in high voltage charging (18v?) note the amperage. And disconnect the field wire. DO NOT LEAVE IT FULL FIELDING FOR MORE THAN A FEW SECONDS!!!!

Then look at the specs of the VR. Can it handle that?

If not look for a Heavy duty VR that can.

 

[Syleng1]

On my 66’ I had the same trouble. I bought one from Classic Industries that looked just like all the other factory looking VR’s but the electronics inside seem to handle the alternator better.
SN: the car had a great ground from Battery to the engine, I installed an additional ground wire from fire wall to back of the engine for Ha, ha’s at the same time I installed this last VR.( I did have a triangle of grounds but added an additional block to firewall)
Honestly, it’s been over 1 year (knock on wood) with zero issues.

 

[67Dart273]

I don't have any idea of the specs on that regulator, a few comments

12 something is not proper charging voltage. Depending termperature, voltage varies, but on a warm day, normal engine temps, charging/ running voltage after the battery has recovered from starting. should be 13.8--14.2

The why of your regulator problems could be.........

1...that there is a partial short in the alternator field winding, which absolutely can and does happen
2...that regulator may NOT be heavy enough to carry the field current of whatever alternator you are using
3...the alternator you are using may have been improperly rebuilt with a rotor which draws excessive field current, AKA out of a heavier duty unit than this one

You want to check that the VR power terminal is not seeing a voltage drop as this will cause over charging, and that the VR is actually grounded to battery NEG potential, which will also cause over voltage

To check this out, get the thing as close as you can to operating temp and the battery "up" and normal. Get the engine running at fast idle and run this test first with accessories off, and again with lights, heater, etc powered on

Stab one probe of your multimeter into the top of the battery NEG post, and the other probe HARD into the mounting flange of the VR to get through any chrome/ rust/ etc. You should read very little voltage, the less the better, and zero is perfect

==================================

To check the power/ field circuit of the VR, turn the key to "run" with engine stopped. Stab one meter probe into the top of the battery POS post. Leaving all wiring properly connected, probe the IGN terminal of the VR. You will again read a little voltage and the less the better. If you read more than .3--.4V (3/10 of one volt) find out why. If your car is factory wiring, the usual suspects are poor terminals in the bulkhead connector, the igntion switch connector, the switch itself, and possibly at the ammeter. This voltage drop when running causes the VR to ramp up to make the IGN terminal 14V rather than the voltage drop it is seeing. THAT causes the battery to see higher voltage. If the VR is properly operating at 14V, then add that to the voltage you measure in both the ground test and this last test, and the total will be close to what you see at the battery.

 

[67Dart273]

WHAT IS the year/ make model of the vehicle you are working on?

Is it American? Does it have stock or nearly stock wiring? What is the alternator you are using?

 

[madmax2]

It's a argentine Chrysler car, a Dodge GTX 1970 with a early a-body. the electrical circuit was old, no electronic ignition no electronic VR.
I connected the Holley EFI directly to the battery with a circuit separate from the car. The original circuit only handles the alt/VR, starter, lights, dash. The EFI circuit handles the ECU, fuel pump, coils, radiator fan.
Run a wire form battery gnd to VR chasis, I checked the voltage drop between the negative terminal of the battery and the chassis, block, alt, vr... all ok

 

[Dana67Dart]

I installed an additional ground wire from fire wall to back of the engine

If you don't have a battery to body ground strap or battery to engine to body, the ground goes through any path it can find.

 

[Syleng1]

If you don't have a battery to body ground strap or battery to engine to body, the ground goes through any path it can find.

I had the triangle- battery to engine, engine to car and car to battery.
I added the braided wire used on ac cars to the back of my engine to the fire wall- ac Cars had this extra braided wire. I was at wits end on why I kept burning up expensive “electronic conversion VRs.” I just know either this made a difference or I finally found a VR that worked right (or as described)
I’m also running a 60amp alternator not a aftermarket high output.

 

[67Dart273]

60A is very likely to have more field current draw. In the old days with the earlier grounded field, the "big" regulator was what was used, looked like this

Don't know why that photo did not show

 

[Dana67Dart]

Powermaster 95A Mopar round back style,

Just noticed you are in Buenos Aires. Can you get stock parts vs generic aftermarket parts? I'm thinking that the regulator can not handle the load of your alternators field. Perhaps an electromechanical (OEM) style can?

 

[MV8]

I found universal VRs under that part number an form factor that showed equivalency to the common Chrysler VR but showed 4 amp field current and 6 amp max. That would explain lasting a little while at 6 amps. Not crazy about the thin steel heat sink either. I also suggest using the standard regulator.