resistor cart motor upgrade?

interstate

Just wondering what gains I may achieve if I upgrade the original 1987 36v motor in my resistor cart to something fresh, like the Plug Quick purple motor.

1. Do stock motor get tired?
2. Can I keep the resistors? I am either full throttle or stopped most of the time.
3. I'd prefer to stick with 36v so save $$ on more batteries and charger.
4. How much speed could I expect to gain?

Thanks guys.

BGW

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OLD MEC

I would contact any suppliers before attempting motor updates. The resistors are your weak point along with 36 volts battery pack. Many owners use the 36 volt motors as they give real boost in power compared to 48 volt motors when converting. I would spend the funds to get your 36 volt motor rebuilt to get it in top condition.

Grinch

I did the PQ bandit on my 89 resistor cart. I also upgraded all wiring to 4G and 23in tires. The old motor tire combo got me 15 mph. Now I'm getting 22 mph with power to spare.

interstate

Grinch,

Does your cart have the vglide controller? Selonoids or bank of resistors?

I would be tickled pink with 22mph.

How much of the speed do you attribute to the tire size increase?

Grinch

I have the V Glide and the bank of resistors, but only one main solenoid. I replaced the wiper and cleaned up the contacts in the V Glide. I purchased the wiper locally for $14. Be careful taking the cover off, it gets brittle over time.

The combination of the tires and the motor was required to get the speed. I just was doing the math and an increase in 20% rpm from the rebuild would have only yielded 18mph (I started at 15). The bigger tires alone, no rebuild, would have yielded 19mph if the motor was strong enough (the circumference of a 23 in tire is 27% larger than an 18 in). I'm getting an 18.5% speed increase above that so I'm getting a faster rpm and the torque needed to turn them. I don't think the old motor would have been strong enough for that size tire as the increased raduis of 2.5" is actually a big enough moment arm to require a lot more force to turn.

Dave

scottyb

Finally ~ Somebody gets it

Grinch

Scotty, you probably already know this but a lot more goes into that highlighted sentence than meets the eye. The equation (from Newton's second law) must take into account alll forces acting against the moment arm trying to move. In addition to the extra distance there is also the weight of the cart, the coefficient of friction between the cart and the surface, the type of surface as shear force is cumulative with a less stable substrate (its easier to move on pavement than sand), wind resisance , etc. Plus the effect of the upgrade of wire; the 19mm diameter of 4G vs. 6G allowing more current to pass. After modifying my cart it is about the same weight, the width of the tires is the same but the pressure in each is now much greater (22psi) creating less drag. With the bigger wires and greater psi, now that I've done some analysis, it is very possible that the old motor might have turned the tires albiet at a very slow acceleration, and on a flat paved surface. My question now is am I being torque limited or rpm limted. I could call PQ and figure out waht the motor rpm is supposed to max out at, do the math based on gearing and tire diameter, or I could alter one variable effecting the equation and see from empirical results. Tomorrow I'm going to borrow a friends narrow high pressure set of 23" trailer tires. If I am torque limited now, I should go faster with those. We'll see.

Grinch

Click on the picture!

Attached Images

Torque_animation[1].gif (156.1 KB, 11 views)

shadowman

come on dude now i have a headache reading all this smart newton stuff.............lol..................

Grinch

Shadow, its more fun doing trial and error too, but sometimes the old ways (former job figuring this stuff on a little bigger scale) creep back in! Don't worry though, my calculus is too rusty for me to start doing public math.

Grinch

GLEEMO

I'm impressed we have jefro , he can sipher