Alternator Lash-Up to Power 385 Planter

I'm cleaning up the 4 row Deutz-Allis 385 planter I bought last fall.  It is in good shape overall, but now I have to figure out how to get enough electrical power to run the fans.  I will be using our D17IV.  The problem is, I just got the generator/regulator sorted out on the D17, and it is working great.  However, the planter needs about 30 amps according to the manual, and the generator on the D17 is barely 25 amps I think.  I hate to stop and change the D17 over to an alternator.

So here's my brainstorm.  I have a good 10si alternator.  Why couldn't I fabricate something to bolt up to the rear pto, and power the alternator off of the pto?  I could mount a battery on the 385, and hook up the wiring with a connector to the alternator, and even use a 3 wire setup.  I will just have to weld up a pulley onto somthing sturdy that I can mount onto the pto shaft - probably just the front portion of an  old pto shaft.  I shouldn't need too big of a pulley, with just a little over twice the diameter of the alternator pully, I would be over 1000 rpm, which should be enough for the alternator.

What do you guys think?  Anyone ever drive an alternator off the pto to run electrics with?

The alternator needs a battery for stabilization. It will spike voltages otherwise. Last i tested a 10SI without regulator but self excited needed more than 1400 rpm shaft speed to build up voltage. One without a battery supply to the regulator takes something on the order of 5000 RPM at the alternator shaft on my 4020 to start. Once started it charges down to 1300 RPM shaft speed. If wired with a battery and a three wire connection it should charge fine at that slow a shaft speed, but you will need some speed to keep the voltage up at the 30 amp load.

They do make weld a hub pulley hubs to fit the PTO shaft.

Look at the belt drive for a PTO driven centrifugal sprayer pump. They speed up that pump a lot on a 540 RPM PTO shaft. You'd only have to adapt the pump pulley to the short alternator shaft.

It would probably be easier to piggy back the alternator on the generator mount driven by the fan or newly added AC belt.

Gerald J.

Ran my 385 last year with no problem with the factory 20amp generator. David

Here's the solution as provided by A-C for the Air Champ unit planters:

There was a control box too, more details are available at AgcoPartsbooks.com

Oops!  Just thought of something.  I kept the stock positive ground with the generator - I don't think the blower motors or seed monitor will like that.

Looks like it would be easier to bite the bullet, and just switch the generator out for an alternator. 

Without digging into it further, it looks to me like the fan on the 10si alternator I have is going to be really close to fouling the power steering belt. 

Anyone with any advice on problems I might run into mounting a 10si to the D17 IV?  Will I need a different pulley and fan on the alternator? 

Thanks for all the help.  Sorry to bug everybody on this.  I wasn't planning on changing out the tractor generator, but that looks like the simplest solution to all this. 

What about finding a portable gas generator that has 12v DC output (along with 110v AC) and strapping that to the planter to run the blower?  Mike