Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo Auction Link (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Tractor Talk Discussion Forum

Hooking up a Motorola Alternator

Welcome Guest, Log in or Register
Author 
JackT

11-14-2005 15:47:01




Report to Moderator

I have a single wire 84 amp Motorola alternator I want to mate with a small Briggs engine for off-grid battery charging. I had the alternator tested at a auto parts house and it tested fine. I can't get any juice out of it with the Briggs engine though, no matter how fast I run it. Its got 4 studs on it--GND, REG, OUTPUT, and STA. The solid state regulator is connected to the REG and GND terminals, I hooked the battery to the OUTPUT and GND, and left the STA open. I've been told that's just unrectified stator output and doesn't need to be hooked to anything. Suggestions?

Thanks

[Log in to Reply]   [No Email]
RodinNS

11-15-2005 07:16:57




Report to Moderator
 Re: Hooking up a Motorola Alternator in reply to JackT, 11-14-2005 15:47:01  
Did you get that Motorola off a Ford tractor? It sounds the same as some of the ones they used in the 80's. I generally never bothered trouble shooting them too much.... If there was a charging problem with either the alt or regulator, I felt it was cheaper to go to a Delco alternator..... . The way I looked at it, if the reg was bad today, then the alt will probably be bad tomorrow, and the Delco was only a little more money than the reg, never mind the alt. However, if I remember correctly, the Reg wire is the sense wire to the regulator, while the Stator terminal is actually the excitor terminal (stator or field), so if you're going to make that thing charge, you need to apply current to the stator terminal. If you want to run without a regulator, then just drop full voltage to the stator, if not, then a wire from the regulator will need to go on there... I think.... I'll look up a wiring diagram this evening when I get more time. HTH.

Rod

[Log in to Reply]  [No Email]
JackT

11-15-2005 13:17:08




Report to Moderator
 Re: Hooking up a Motorola Alternator in reply to RodinNS, 11-15-2005 07:16:57  
Rod,
The alternator is off an Elgin street sweeper so yes, it could have been a Ford engine. The solid state regulator is attached directly to the alternator and contains the brushes that contact the slip rings as well. Its wired to the REG and GND terminals. No other wires appear to have ever been attached to either stud. They're caked with dirt/grease and were this way when I took it off the sweeper. There was a heavy wire connected to the OUTPUT terminal and a lighter one to the STA. I was told that was probably used for an electronic tachometer. I'd like to use this alternator because of its hi capacity output (need it for charging off grid batteries).

Thanks

[Log in to Reply]  [No Email]
RodinNS

11-15-2005 17:46:39




Report to Moderator
 Re: Hooking up a Motorola Alternator in reply to JackT, 11-15-2005 13:17:08  
Hi Jack,

I should have looked at the wiring diagrams first. I think you're right about that stator terminal. It will probably just sit unused. Now, as these Motorola's were used on Ford tractors, the alt was not internally regulated. The alt had a field terminal, as well as an output, Reg, and ground terminal. In this setup, there was a wire from the reg to the field, from the reg to the alternator ground terminal, and another wire from the reg, in parallel with a wire from the key through the charge indicator light, that went to the alternator Reg terminal. So, at a guess, I would say that you need to wire an idiot light into that circuit. Basically, run a wire from the key to the regulator, and then "T" the indicator light into this wire, with the other end of the indicator light wire going to the "REG" terminal on the alternator. Again, this is simply how the tractors were wired, and I'm describing the wiring diagram as best I can. Your situation may be different, but I would suspect that there would need to be some form of indicator light, and that this would provide the initial "excitement" through this wire. Otherwise, I would expect that this alt may have some problems..... In that case I would just go to the local auto parts store and get a reman Delco 10si. They're available in a range up to about 100 amps, and easy to wire. Anyhow, good luck, and if you need more info shout back.

Rod

[Log in to Reply]  [No Email]
Hermit

11-14-2005 18:18:29




Report to Moderator
 Re: Hooking up a Motorola Alternator in reply to JackT, 11-14-2005 15:47:01  
You might want to borrow a Chiltons or Motors manual and look at the alternator/regulator schematics. My books show the STA terminal is for the stator and connnected to ground through a resistor. And there are various regulator types that connect differently. You might have to get a regulator specified for that type alternator.



[Log in to Reply]  [No Email]
Ray

11-14-2005 17:41:31




Report to Moderator
 Re: Hooking up a Motorola Alternator in reply to JackT, 11-14-2005 15:47:01  
I would try another brand of alternator,those motorolas are trouble and expensive to repair.
I have one on a JD 2030 tractor that won't start to charge till the engine is run up to about 1200
rpm.I had it rebuilt and it is the same way.If that's the case you couldn't make it turn fast enough to charge with your outfit.



[Log in to Reply]  [No Email]
bfloyd

11-14-2005 17:15:58




Report to Moderator
 Re: Hooking up a Motorola Alternator in reply to JackT, 11-14-2005 15:47:01  
An alternator requires excitation voltage or it just won't put anything out. If the battery is dead the alt won't put out nothing. If you had a generator the gen will charge up the 100% dead battery but an alternature wont If you hook this puppy up wrong you will cook it or the regulator or both. The regulator also needs to sense the alternator voltage so there should be one more connection for this to work. The alt will work without any regulator at all but it will toast your battery. The alt output goes to the bat and reg bat terminal. I think the STA goes to the regulator sense terminal. Hook up the sense lead and it will work fine.

[Log in to Reply]  [No Email]
doogdoog

11-14-2005 16:42:32




Report to Moderator
 Re: Hooking up a Motorola Alternator in reply to JackT, 11-14-2005 15:47:01  
Aloha, I don't know if this will help but, I think that there should be 3 wires going to the reg. Are you using a 3 or 4 wire harness? I am looking at an old schematic of a Motorola reg and it shows at least 3 wires. Black goes to grd. orange goes to alt. reg terminal, and green goes to + terminal of rotor field winding. Hope this helps.

Mahalo,
doogdoog



[Log in to Reply]  [No Email]
ebbsspeed

11-14-2005 19:39:26




Report to Moderator
 Re: Hooking up a Motorola Alternator in reply to doogdoog, 11-14-2005 16:42:32  
I agree with doogdoog. I think you have a 3-wire alternator, not a 1-wire. Sounds likt it needs an external regulator. Take the advice of a couple others on here and find a Delcotron. Easy to connect, reliable, and easy/cheap to repair if you need to.



[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy