XCT 500 programing

[Helirich]

Originally Posted by Volt_Ampere

Yes you could change the max RPM to 5000 and probably see no difference in your max speed. You might notice a change in the throttle response. Larger diameter might mean lower Max RPM if the armature is actually also larger diameter. The forces on the armature go up as the diameter increases and as the speed increases.

This got me thinking. If I have the tires off the ground and the pedal to the floor and it goes to 6000, then I back off 1/2" on the pedal and it goes to 5000. That would mean that when it's under load, the last 1/2" is of no value. (I can't get to 5000 or 6000.) so that would mean that I should make the max rpm just a little over what ever 26 mph translates into rpm. Am I thinking right?

[JohnnieB]

Originally Posted by Helirich

1. So if I jack up the rear, (tires off the ground) the motor would turn 6000?

2. I know I read that a stock motor will not explode at 6000. How about an aftermarket motor?

3. Mine is bigger in diameter than the stock motor. Should I be worried?

4. I guess I could change the max to 5000, since I can't get there. (Unless a hill)

1. Unless there is something other the the rolling resistance of the low pressure tire holing the motor RPM down, it should.

2. Mechanically, 6000RPM is a conservative max RPM for just about any electric motor typically used in golf carts and very conservative for many of them.

In some instances stock and aftermarket motors are made by the same manufacturer. A stock motor is actually an off-the-shelf motor chosen by the golf cart manufacturer.

The limiting factors for RPM are how well balanced the armature is, how well the armature is held together and the RPM restrictions imposed by the bearings on the shaft.

IIRC, you are running the same motor I am (D&D ES-76-51). I received two different max RPM recommendations from D&D, Vic said 6000 and Eric said 6500. When my cart is at max speed, the motor is turning in excess of 7000RPM, however I typical drive at 25 MPH or less, which is 6135RPM with my tires height and gear ratio.

3. You nothing to worry about regarding RPM. I'd be more concerned with motor temperature.

The ES-76-51 is the same diameter as the stock PDS motor since it mounts to the same bolt holes on the differential and does not have a bottleneck case. It is an inch or so longer than a stock PDS motor.

I believe the armature diameter is the same as the stock motor also, or at least it looks to be in the attached photos. The mounting bolt holes are on 6.175" centers and can be used as a length reference if you want to do some measuring on the photos to find out for sure.

Also attached is a side by side photo of a stock PDS motor and a ES-63-49, which is 0.76" longer than a ES-76-51.

4. Setting it to 5000 would limit your max downhill speed to about 29 MPH, but I don't know if it would effect performance otherwise. Contact Alltrax to find out.

[JohnnieB]

Originally Posted by Helirich

This got me thinking. If I have the tires off the ground and the pedal to the floor and it goes to 6000, then I back off 1/2" on the pedal and it goes to 5000. That would mean that when it's under load, the last 1/2" is of no value. (I can't get to 5000 or 6000.) so that would mean that I should make the max rpm just a little over what ever 26 mph translates into rpm. Am I thinking right?

No. Comparing pedal position vs RPM with different amounts of load (drag) is an Apples to Oranges comparison.

With the rear tires in the air, it may only take a 10% duty cycle on the PWM output of the controller to spin the motor at 4500RPM while it takes 100% duty cycle to reach 4500RPM when the tires on on the ground.

It is sorta like keeping a helicopter's the nose pointed straight ahead in a crosswind. The stronger the crosswind, the more pedal it takes.

[Volt_Ampere]

I upgraded to a D&D motor after I cooked my stock Hitachi motor in my Yamaha. It runs way cooler (I have a thermal probe attached to the case near the terminals). I am not sure what the major difference is but with the same performance it isn't getting anywhere near as hot as the stock motor did.

[Helirich]

Ok, I guess there's no reason to change the max rpm setting. I was just thinking I could get more "usable" pedal travel.

I just looked and the motor is not a different diameter from a stock PDS. I don't know why I was thinking it was bigger diameter. It is longer by 1 1/2".

The manufacture is "Advanced motors and drives." I think it is the same company that made my stock PDS motor. The model is a EY7-4001.

Your motor maybe the same as the new Beasts have. It is D & D and is 16 hp. Mine is the "old" beast motor. It is only 12 hp.

[JohnnieB]

Originally Posted by Helirich

Ok, I guess there's no reason to change the max rpm setting. I was just thinking I could get more "usable" pedal travel.

I just looked and the motor is not a different diameter from a stock PDS. I don't know why I was thinking it was bigger diameter. It is longer by 1 1/2".

The manufacture is "Advanced motors and drives." I think it is the same company that made my stock PDS motor. The model is a EY7-4001.

Oops, I thought we had the same motors, I guess my memory failed me.

An AMD EV7-4001 is a high-torque/mid-range speed motor, so your tires aren't costing you quite as much speed as I thought they were.

If you happen to have a yardstick handy the next time you are close to your stock PDS motor, would you measure the case length, not including the bulge of the speed sensor.

I never thought to measure the length and my exploded PDS motor is in the scrapyard.

As for usable pedal travel, that is what the Throttle Linearization, Throttle Torque and Throttle Speed settings are for.

[Helirich]

My PDS motor is 8 1/2" from the gearbox edge to the outer curved edge. (Not the speed sensor bulge) My "Beast" motor is 10" at the same places.

I have the programing about as good as I can get it. Most of my driving is in the 0-15 mph range. So I have I have it set so I can control it there. But when I get past a point on the pedal, it kind of jumps.

It's funny how a car goes lots faster than that, same pedal travail and it's not jumpy.

[JohnnieB]

Thanks for the PDS motor length. I put it in a drawing so I can find it in the future.
It appears that my motor is 1.74" longer than stock.

As for the jumpy stuff on the pedal, try clearing the throttle auto-cal and make the XCT relearn the throttle limits of your specific ITS sensor. (Sometimes you need to do that after making changes.)

Also, what is happening may show up on a data log. Save as a csv file, zip it and post it.