2940 Alternator change

[caterpillar guy]

I have a 2940 with the Motorola alternator on it. Can I easily just bolt a Delco on it and connect the wires from the tractor to the appropriate location and have it work? Or do I have to stay with the Bosch/Motorola program. Delco would standardize things for me. Looking at All State Tractor parts site The wiring for the regulator shows just 2 wires that actually go back to the tractor besides the wire to go to the battery so thought one to light and one to the ignition switch would solve the excite and charge connection problem. Asking before I start.

 

[Tx Jim]

What you states sounds correct. If I had a tractor with a Motorola alternator I change it over to Delco alternator before repairing a faulty Motorola alt or regulator.

 

[Jim.ME]

A Delco can replace the Motorola. The wiring diagram in your service manual will ID wire function for correct connection to the Delco. I would use a 3 wire Delco type and plan on buying a small diameter pulley the right width for your belt (I don't remember for certain, but I am thinking the Motorola pulley won't fit the Delco).

 

[caterpillar guy]

Jim.ME According to All state ag parts the purple and orange from the regulator were the wires for the ignition, and the light. So I figured if I just used the plug off the old alternator it would already be wired for the light and switch which would then be easy to make work if the alternator would fit on without a lot of work. Otherwise I guess I would just put the OEM type on.
Thanks guys.

 

[Jim.ME]

(quoted from post at 10:04:14 02/07/22) Jim.ME According to All state ag parts the purple and orange from the regulator were the wires for the ignition, and the light. So I figured if I just used the plug off the old alternator it would already be wired for the light and switch which would then be easy to make work if the alternator would fit on without a lot of work. Otherwise I guess I would just put the OEM type on.
Thanks guys.

As long as you know which wire is which you should be all set. Excite power should come to the #1 spade terminal on the Delco through the indicator light. The switch wire should cover the sensing need for the #2 spade. The Motorola plug may not fit the Delco terminal port, but you know which is which and where they go.

 

[WTW]

The 2940 never had a Motorola it was originally factory equipped with a Bosch from Germany.

 

[Jim.ME]

(quoted from post at 10:57:00 02/07/22) The 2940 never had a Motorola it was originally factory equipped with a Bosch from Germany.

I figured no need to go down that road. True, they were Bosch, but it might have been changed to Motorola over the years. Please correct me if I am wrong, but I believe the same principles apply to both, to convert to a Delco internally regulated unit. And I believe Motorola makes a regulator that will work on the Bosch alternator so when people look at it, the Motorola on the regulator is what they readily see and call it.

 

[Tx Jim]

I agree Bosch alternator/regulator could have been changed to different brand in the last 40 yrs.

 

[caterpillar guy]

These are the Deere part numbers from the Alternator AT27827 and regulator is AR78298 Model is 8RF20146 Both pieces say Motorola on them.

 

[Jim.ME]

I don't doubt one bit what you have. Those part numbers don't show up as being used on a 2940. Have you owned it since new so you know the alternator was never changed? As I and Tx Jim posted, that alternator was likely installed when the previous one failed. Maybe the Bosch wasn't available, or it cost a lot more than the Motorola. Maybe similar to your situation a previous owner had others with Motorola alternators and wanted to make this one the same as the others, so one spare would cover all of the fleet. They are all similar so swapping them around isn't hard. You will be fine putting a Delco type on it.

 

[caterpillar guy]

JimME: I was just showing it was a Motorola for both the alt and reg. I have no idea what was the original on there. We have owned the tractor for about 10-15 years. It's been a pretty good tractor. I really like the MFWD on it. Have only had to replace the bushings on the hydraulic pump drive in front a water pump and the Solenoid for the front axle and now the alternator. Oh we also changed the front tires when they wore out.
Thank you guys for the help on this. I'll get back when I get done with it.