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[cgtech]

I have never seen a PDS conversion with a mechanical F&R, always F&R relays.

[JohnnieB]

Originally Posted by kojo

JohnnieB,the reason I'm thinking about doing this is that I'd like to speed it up to around 35-40, and the way I understand, that speed with a shunt motor won't last because it will probably get to hot, and that a series motor doesn't get as hot and would do fine getting up to that speed with a gear change.

That information is not correct.

The motor in a properly designed shunt (aka sepex) or series drive system, with a battery pack with sufficient voltage and ampacity, will spin in the 6,000-6,500 RPM range with a case temperature below the 239°F Max, and if the final drive ratio (Gears and tire height) is correct, the cart will be moving in the 35-40 MPH range.

In general terms, a series motor is a better starting point for a low speed applications like hauling stuff, driving through deep sand/mud and climbing very steep hills, or creeping along at walking speeds and slower. However, a sepex motor can be designed (wound) for Low-speed/High-torque applications.

For high speed applications, I don't think it matters too much between series and sepex. They can both be wound to reach high RPM (~6k-7k) without overheating.

Basically, overheating is a sign that the motor doesn't match the rest of the drive system.

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I agree with Olman about speed and stability.

[kojo]

JohnnieB, I have given the thought of a motor like yours, ES-76-51 motor, I think it would probably be pretty much what I need. How long have you had yours? I know you have some hills where you live, so it must have pretty good torque.

[kgsc]

Kojo, last cart we built we went from series to a sepex. Cart has a 2 speed Curtis 1268 500 amp controller, 15 to 1 posi rear with 26 inch tires and a D&D motor. Cart runs 16 in low with tons of torque and 26 flat out in high. It took some tweaking with a programmer but turned out nice. I wouldn't attempt another one without the programmer so looking for one now.

[kojo]

man kgsc, 26" tires, that's a pretty good size tire, but the 15:1 gears help I guess. Sounds like a pretty good setup w/ a sep-ex. I've heard about the 2 stage series motors you can get but I didn't know you could do it w/ a sep-ex motor. But, I think you done it w/ the controller didn't you?

[kgsc]

26s with the 15:1 I figured were close to 23s with the stock 12:1 so yes it helps plus posi

2 speed is done with controller and it allows you have 2 separate programs for the motor hence torque for low and speed for high. Top speeds in each can be limited so also makes an excellent kid friendly cart.

I want to do another one in a little less extreme configuration and see how it behaves but the programmer is a must.

[kojo]

kgsc, how much does a programmer cost? That thing should pull like a Belgium horse.

[kgsc]

I'll let you know when I find one

I've seen 250 that I should have bought to over 1k.

Pretty sure I know where I can borrow one but don't want to be rushed to get it back.

[kgsc]

Originally Posted by kojo

kgsc, how much does a programmer cost? That thing should pull like a Belgium horse.

And yes, with a long top, rear seat, lots of extras and a 325 lb man loaded it will pretty much spin the tires up this dirt hill near us.

[kojo]

Ladies & gentlemen...........that's power.