Motorola Alternator

As long as you don't exceed the capacity of the amp meter (if you have one) . I ran in to that with my 35 amp alt. and 40 amp meter.
Can't go to 55 amp without changing amp meter. mine has to stay original so no voltage gauge or etc.

 

IIRC all the regulator (VR) does is adjust the alternator field voltage until the output voltage is at the target, like 14.3V or whatever. There is a voltage reference (typically a zener diode) in the VR that the VR compares to the charging voltage. The change in charging current is a response to the higher output voltage, and a result of Ohm's law. So there's no need for the charging current to go through the VR - all the VR sees is the "sense voltage" - the difference between the reference voltage and the battery voltage.



Here's a diagram of a Delco alternator, with the VR internal. Component D1 is the reference, a zener. Transistor TR1 conducts to supply current to the field (rotor) through the two slip rings and brushes. The field rotating in the stator produces three-phase AC, which is rectified by the rectifier bridge into full-wave DC. The field is initially supplied through the switch and indicator lamp (terminal 1, light is on), until the alternator self-generates and supplies field voltage to the VR through the diode trio. When self-generating, both sides of the indicator are at full voltage, and the light is out. Terminal 2 is the sense voltage.

Your Motorola alternator is basically the same, except the regulator is outside the alternator. If the VR is ok, the usual problem with the alternator is it's worn out (brushes and bearings) or the diodes are kaput. We used to replace the diodes back in the day, and you may still be able to get the parts. However, complete replacement alternators are typically too cheap to make parts replacement economical.

 

just supply me with a part number to a modern, direct fit/bolt in replacement alternator with an internal voltage regulator please.
I read (tried to) your entire post, and my head swims.

 

I am hoping this post above is correct. I just got a NOS Motorola alternator - 55 amp. I am going to install it to replace a 35 amp Motorola (1971 CJ-5 with V6). I was reading the factory service manual and it seems to confirm that stock Motorola voltage regulator will work with either the 35, 44 or 55 amp alternator option. The manual indicates a different voltage range for testing the 55 amp (compared to the 35 and 44) for when you are doing some of the alternator tests. However, it appears the stock regulator should work with all there amp options.

 

Ran into an issue. Got a new alt, and the mounting brackets aint gonna work here.

 

I don't see it . where's the problem . is it the pulley

 

Yes. Different thicknesses, so id have to offset mount it/fabricate brackets

 

Do you cut the swing arm away from the slot and re weld it for exact alignment? OR is it the base gets modified to move the alternator to the rear and leave the swing adjusting arm alone?

 

Idk. All new to me.why cant i get a direct replacement?

 

That pulley on the Motorola should swap to the delco. The F heads use a wider belt than the v 6's.

 

Check Rockauto. It looks like they have your replacement.

1970 JEEP CJ5 2.2L 134cid L4 Alternator / Generator | RockAuto

 

Rock auto has left me high and dry too many timea. I have the f134

 

Rockauto is the absolute best out there right now too. Without them, I would be out of business. No local parts houses left here.

 

Like I said in my post, I used a GM one wire alternator, cut enough off the back of the mount on the alternator to make it line up with the front pulley on the crank pulley,with an abrasive wheel, then put a new pulley on the alternator for the wider belt. Then made a spacer to fit the tensioner arm to the GM tensioner tab on the alternator. That way I used the Motorola brackets to fit a GM one wire to my F134, and it wasn't a lot of money, has worked for 10 years now. You could use a 1/2" fan belt on the wider crank pulley if you don't want to change the GM pulley. I made a mounting bracket to mount a GM alternator on my other motor without modifying it, either way, I think the GM one wire is the easiest and least expensive way to up grade my charging system, works for me. Good luck

 

Allright. Bought a direct fit for my jeep. But its a 37 amp, not a 51 amp like my motorola. Should be fine for the likes of me. Remy brand, model 20170.