alternator info

Thank you very much for your answer.
We've been using your products for almost two years now in small and large bus air conditioning units, and we've had a satisfactory performance.
Now that I've been looking deeper within your product catalog, I have a few doubts for a new application that we are working on, and an actual one:

1. We are interested in the AVI128 alternator (12V - 110A), but we find 6 different part number. What's the main difference between these models?
2. We are currently using your 110-575 alternator (24V-150A)in large bus air conditioning units, and we found in your buyer's guide brochure that we should install along with the alternator a discharge circuit parallel to the "load" (air conditioning system). I guess this is for turning off the unit issues, but what are the parameters to design that circuit? what value of resistance and capacitor should we use?. I'd appreciate if you could give me the parameters to design the circuit so we can start carry it on for now on.
3. COuld you please send me a piece breakdown for the AVI128 alternator Part # 35214610? I'd like to see where's the regulator located, and to know what does an external rectifier mean?

Thanks in advance for your attention. I look forward to your prompt answer.

Alejandro Valencia
Colombia - South America
Company name: Transtermo Ltda.
PBX: 57-1-6178837
Mobile: 57-312-4805791

Alternator info.

I'd like to know what's the main difference between the diferent mounting types. There's "spool", "saddle", "dual foot", etc...

I'd really appreciate if you could give me information about this type of mounting, so I can choose the best alternator for our application.

Alejandro Valencia
Colombia - South America
Company name: Transtermo Ltda.
PBX: 57-1-6178837
Mobile: 57-312-4805791

Permanent Magnet Alternators

Does Prestolite have a permanent magnet alternator?  I know at one time you did or were developing one for a 28 Volt system.  I acquired a PM alternator from a company based in Mexico and must say that I am impressed.  I have over 175K miles and all is well.   


Leece Neville A0012800LC alternator

Does the aoo12800lc alternator have a bilt in regulator or does it use an external one. also is the AC terminal post were you would energize the alternator.thank you.

VLF Alternators

Most of your VLF series Alternators are discontinued. Do you have any 24V 300 amp alternators left. If yes, how much are they and what RPM & Horse Power is required to reach maximum output?

Thank you very much for you reply.


Don Broderick

8RL2126 Rebuilt or kit

Cat Challanger

alternator rotation

In general can I change an alternator's rotation just by changing the fan?

 If not please say why (so I can understand the problem)

Discussion:- I want to fit a second / reserve alternator, and can only fit a unit in the "opposite direction".

 I have available 8LHA and 110-444 24V 70+ amp units both of which are CW rotation.

(The next challenge would be to source the fan!)

May be a dumb question - but if one doesn't ask...

Motorola 8MR2048K Alternator Tach Signal


I have a Motorola model 8MR2048K alternator on my marine diesel. I am replacing the engine tachometer that receives the engine speed signal from the Motorola alternator (via the AC tap or tach signal terminal). To program the tachometer to indicate proper engine RPM, I need to know the number of poles the Motorola 8MR2048K has. I will then multiply this by the crankshaft/pulley diameter ratio and have approximate pulses/engine RPM. Please, could you tell me how may poles the above alternator has? Just curious, is this alternator similar in operation to automotive alternators which are really 3-phase and use six rectifiers for full-wave rectification? I assume the ac tap or tach signal terminal is just the voltage waveform from one of the phases prior to rectification.
Any technical advise will be muchly appreciated! (Pennsylvania Dutch)

Overcharging Alternator

I have two failed regulators Part No. 1861652 associated with twin AC203 alternators fitted to a railway vehicle. The regulators are short circuit such that the output increases with engine speed. Changing the regulators fixes the problem.

My questions are:

1. What could cause the regulators to go short circuit?
2. Is this type of fault unusual?
3. Can the regulators be repaired and if so by whom (in the UK)?
4. What type of main fuse should be fitted in the charging circuit?


John Conlon

Replacement Alternator

Is there a modern equivalent available for a Prestolite 9RC3041 24V alternator? Is there tech info available on either the obsolete alternator or a replacement?

Thank you.