I need an alternator.

[avengeusa]

just bought a 24 volt alternator off ebay for 100.00 teds trucks and stuff have dealt with them alot great to deal with

which model?

27si, 21si, or 22 si?

I am going to stick with the newer units, they are more reliable, and the price is right

 

[OPCOM]

which model?

27si, 21si, or 22 si?

I am going to stick with the newer units, they are more reliable, and the price is right

Is there any bolt-on model capable of more than 60 amps? Like 200A or 300A? i see DC generators for aircraft that have those ratings and are not much bigger. They are spline drive. It could be an issue of the belts and pulleys being able to take it.

 

[tomesee1]

it is a 60 amp havent got it yet i couldnt find a newer one that i wouldnt have to change the mounts not a cheap one anyway

 

[avengeusa]

Is there any bolt-on model capable of more than 60 amps? Like 200A or 300A? i see DC generators for aircraft that have those ratings and are not much bigger. They are spline drive. It could be an issue of the belts and pulleys being able to take it.

one could be built, or found.........

70+ amps is a lot at 24 volts, it is like having 150 amps at 12 volts, lots of power

 

[wvhillbilly]

Check this Source!!!!

Contact "Electrical Motor Service" in Logan, West Virginia. I do not have the toll free number here at the house, but email me at LEWWVA@FisherAutoParts.com and I will reply with the toll-free number. Use them all the time to source rotating electrical parts. They are a nationwide supplier, reputable, knowledgeable, with fair pricing...Have always had what I needed for military alts./starters.

 

[tedstrucks]

Guys, I have LOTS of the 60, 100 and maybe a few of the 200 amp alternators. We check them over and test them before we send them out. I'm not in the office right now, so I don't remember the price, but the 100 and 60 amps are on ebay. Call tomorrow if you have questions (334-983-1092). We don't know near as much as some of the guys here on the forum, but we aren't afraid to talk to you on the phone. ;o)

 

[reloader64]

To resurrect an o;d thread....I bought a 27si alternator, using the Lester number listed above. At first glance, I assumed (and you know how THAT goes) that it wired liked every other Delco I've hooked up. Then I noticed the second isolated terminal, near the battery terminal. Then I noticed that the 2 tabs poking out from inside the case are actually connected. Much perusing of the internet resulted in many wiring diagrams for generic GM alternators, but little else. Can anyone shed a little light on this? And pardon the art work. I've lost my camera.

Scott

 

[greg2560]

look at this link it might help you http://kb-kbh.dk/shipslib/el_ombord/alternatorhandbook_ocr.pdf

It has 12 and 24 volt info.

 

[reloader64]

Cool, thanks!

 

[goldwing2000]

If that didn't tell you exactly what you need to know, I found this info today:

Optional connections to the 21-SI series, include “R”
(relay) and “I” (indicator light) terminals, and a ground
lead connection to the alternator housing.
A Relay terminal may be located either counterclockwise
from the BAT terminal where an R is molded into the
casting, or at an opening clockwise from the BAT terminal
and labeled “RELAY” by a permanent adhesive label next
to the terminal. On a replacement unit, there will be a round
push-on label on the terminal itself. This terminal may be​

used to operate a charge indicator, ADLO system, tachometer, or similar device by providing voltage pulses

at about half of system voltage and at a frequency of 6
times the alternator rpm.
When an “I” terminal is present it will be located where
there is an I molded into the casting, clockwise from the
BAT terminal. An “I” terminal is connected internally to
the field circuit. If an indicator light is connected in series
with this terminal, the light will be on whenever there is a
voltage difference between the “positive” side of the field
circuit and the system voltage at other side of the indicator
light. During normal alternator operation, the light will be
off since the diode trio output voltage equals the system
voltage.
The R and I terminals are available in either threaded (10-
24 or M4) or pin types.
A threaded 1/4” or 5/16” hole in the slip ring end (SRE)
frame is provided to connect a ground lead if used;
otherwise, the ground path is through the mounting
hardware and brackets to the engine.
Some applications use a debris shield on the outside of the
SRE housing of the alternator. Such shields are added by
the engine manufacturer to reduce the amount of airborne
debris that enters the alternator in severe environments. A
stud mounted in the “I” terminal hole may be used to attach
the debris shield to the alternator. The stud is not connected​

electrically inside the unit.

 

[goldwing2000]

Double Post

 

[reloader64]

I installed my alternator, connected the ground and the main wire, and started the truck to test the unit by checking the voltage output with the sensor wire both connected and disconnected. It seemed to be working fine either way, so I assumed that it worked like a 1 wire alternator. Left the sensor wire disconnected. Drove about 60 miles to a parade, gauge reading in the green all the way. Several stops and restarts, everything fine. Almost home, stopped at my shop about 10 miles from my house. When I pulled out on the main road, I noticed the voltmeter was moving in direct relation with engine speed, up to the upper limit of the gauge. Stopped, checked connections, couldn't find anything obviously wrong, so tried to limp home as close to idle speed as possible. After a few minutes, noticed the gauge was reading correctly again. Did this a couple more times before I got home. Pulled the unit off the truck, opened it up, checked everything, no apparent problems. Put the alternator back on, hooked up all the wires this time, tested it, seemed to be working fine. With the tools to unhook the main wire close at hand, set out for the next parade. Unit worked fine, and has been ever since. Conclusions? After starting out the first time with fully charged batteries, maybe the voltage got low enough to prompt the alternator to start charging, but without the sensor wire hooked up, unit just went to full charge mode? Don't know for sure, but with the sensor wire hooked up, it works like a champ! On startup, it does have to reach a certain RPM before it starts charging, but after that, it maintains voltage, even at idle.

Scott

 

[goldwing2000]

Which alternator are you using and to which terminal did you connect the sense lead?

 

[reloader64]

I googled "lester 7197", having read that in one of the early posts in this thread. This led to a supplier, whom I can't remember, selling Chinese copies of Delco alternators. This is listed for a tractor, or some sort of construction equipment. On the Delco 12 volt civilian models, there are 2 tabs sticking up out of the back of the unit. One is the "sense" wire, and one is the "exciter" wire. I noticed on the Chinese unit that both tabs were connected together. I connected the exciter wire from the truck to one of those terminals. I assume (and you know how that goes) that the exciter wire, having voltage on it when the switch is on, could also be used as the sense wire. The bottom line is, I really don't know what I did. But it does work, so for about $120.00 and a little grinding on the mounting brackets, I have a brand new alternator, vs. a takeoff for $150.00, which is the cheapest I could find.

Scott

 

[goldwing2000]

Ok, so you hooked up to the 2-wire terminal in the rectangular hole in the top of the alternator. Good to know. I just picked up a 21SI (Lester #7642) off eBay for $63 shipped. I'm working on the bracketry now, so it could be useful to hear the problems others have had. My 2-wire terminal has a rubber plug in the hole, so I'll just hook it up as a 1-wire first and see what happens.

 

[goldwing2000]

Finished my bracket. I like it better than the "flip the alternator over and put a huge contraption on it" method.

Also bored out the stock pulley instead of buying a new one and finding a spacer.

 

[DavidWymore]

Finished my bracket. I like it better than the "flip the alternator over and put a huge contraption on it" method.

Also bored out the stock pulley instead of buying a new one and finding a spacer.

I like it. Looks like it gets the alt up higher off the filter. Installed pics? Did it weld like cast iron or cast steel/nodular?

Thanks