rexmundi

I have a few problems getting it ready for the road after a long spell.
First problem, when first started runs like a dream, when turned off then restarted, it wont idle and runs very rough, let it cool down and the story starts again, runs fine, then after restarting runs as rough as.
Second problem, it has a electronic voltage regulator fitted with a glass 3A fuse, keeps blowing the fuse .........help please

moparted

no regular has a fuse

440roadrunner

Let's see a photo of this fuse?

rexmundi

here is a pic of the Voltage regulator

TVLynn

That's not a stock regulator !!!! Aftermarket/ homemade big black transistor probably shorted

440roadrunner

OK UNhook the green "quick connect" green field wire from the alternator This is going to be somewhat tricky. What you want to do is measure field current, but first you want to be sure the field is not SHORTED. This would damage your meter if you tried to measure current right away. That is, a multimeter measuring current is in series with the battery.

So with engine off, set your multimeter on "ohms" and measure from the brush terminal of the alternator to ground. Take care to do this carefully and obtain an accurate measurement.

Consider ohms law, which for current (amps) is Amps = voltage / resistance

Let's say you measure the field at 4 ohms. You have 12 volts. 12 divided by 4 is 3 amps. Should not blow the fuse. What would be wrong. Is the green field wire shorted between the alternator and the regulator? Check that out?

BUT lets say you measure the field terminal at 1 ohm, 12 volts divided by 1 ohm is 12 amps!!!! This might mean the brush holder is shorted to ground, or that the rotor in the alternator is shorted.

rexmundi

Thanks 440.....I will check that today

rexmundi

440.......I have done what you suggested, I done the test between the terminal the green wire was on at the alternator and a good ground on the body, the reading was 0.02 ohms........................does this mean there is a short in the alternator?????

440roadrunner

Boy it certainly sounds as if. I would pull the alternator off the car and inspect. These are simple. The rotor is an electromagnet. Depending on the year model, they draw somewhere between 3 and 6 amps at 12-14V so you would be expecting several ohms as I mentioned above. Most likely is a broken brush holder.

Once you get it out "where you can get at it" and remove the brush holder you can physically inspect the brush holder for damage. Then you can measure the rotor for resistance directly

Did this recently start happening on it's own, or have you recently replaced the alternator? If so, a poor rebuild would be suspect

Also, if you can, post a photo of the alternator.

rexmundi

Regulator is out, here are some pics..
It has something rattling around in it, I will strip it down and see what the story is.
Thanking you 440, you have been a great help

TVLynn

That is not the typical 1969 Mopar alt.

440roadrunner

It certainly is not. Rex, where are you, are you in the states? That is a Ford? Bosch? I'm not sure what? You can see the terminal marked "field" If it is the terminal showing the very low resistance to ground, I would say the field is shorted or that the brush holder is shorted.

rexmundi

Yes 440....... I'm am in Australia, these cars were bought in in knock down form, the alternator is a Email, they were used on all aussie Chryslers at that time.
The FLD terminal is the one I tested, and I will keep you informed of what I find.
Your info I have found through out this forum has been very helpful, thank you.

rexmundi

I have pulled the alternator down, brush holders and brushes look ok.
The carbon slip rings look good, should they continuity between them....??