4-1-06 Re: Motor options

Hello to All,

From Jim Husted:  At only 84 volts I doubt you can feed a 9er.  Most people are running 2X to 3X the rated voltage of the motor.

Electro Automotive wrote:

Huh?  Maybe most people you know run 2x – 3x the motor’s rated voltage.  Maybe they are drag racers.  Maybe they melt motors.

Yes, guilty as charged as to the drag racer thing. This happens though, at the ‘very’ high voltages and ‘very high’ currents where we are pushing the performance and durability edge. On the other hand, with expert motor help from Jim Husted, so far, melted motors are a thing of the past for now.

We don’t recommend less than 96V for a very basic street car, nor do we recommend above 144V on the 9″ motor.

I’ve run Blue Meanie’s ‘properly advance timed’ ADC 9 inch motor at 156V for I think, 10 years now. Not a single motor problem, and the original brushes are at around 75% still. Many others, like John Bryan and his 192V Ghia with its XP super torque’n 8 inch ADC motor, have also not had any problems at all….nor has Bill Dube’s 192V Wabbit…this list could go on and on.

>We have this funny idea that we believe in following manufacture ratings, thus maintaining warranty.

I  have this funny idea of knowing the manufacturer (ADC) isn’t smart enough to advance the timing to 10-12 degrees so that their motors will run properly for the market they sell them for…EVs. Can you say Corbin Sparrow? I also have this funny idea of running an EV’s motor at higher voltages for far less average current to keep the motor running cooler, the com. and brushes lasting far longer, and for making power on order with what the gas version originally had (or even more).

I would suggest that running these motors at between 96V and 120V is probably way harder on them, than at higher voltages, because to get any semblance of acceptable power at these lower voltages, the average current needs to be way higher than when run at the higher voltage levels, thus more heat and com. damage. Add in the fact that most of the Electro Automotive designs feature very heavy conversions with lower than average power, and you are asking the motor to work under even more duress. Most of the Electro Automotive designs use the squealing Curtis controller only capable of 500 amps. On a 96V Rabbit, a small car that unfortunately weighs in at over 3000 converted lbs., considering 6V wet cell voltage sag under 500 amp draws, there’s only 40 kw of max power, or just 40 delivered hp to move 3000 lbs. of mass….argh! Talk about a prescription for low performance and an overheating motor!

The 108V Ford Escort conversion I used to own that I lovingly named ‘Sluggo’ had a 9 inch GE motor that got so hot I could barely touch it. With its low performance Curtis controller and low performance wet cell pack, this over weight 108V EV had miserable acceleration and hill climbing ability, and a motor that was always very hot due top high average currents at low voltages.

I find it rather amusing to hear Shari arguing motor durability with the likes of Jim Husted, a guy who’s adult life has been immersed in electric motor design and repair, a guy who makes his living working on all models of DC motors for EV use, and the guy who co-designed and built the world’s most powerful, the world’s quickest and fastest, and world record setting 8 inch DC motor!

See Ya……John ‘high voltage’ Wayland

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