Re: (ET) dynamic braking

[Daystar Energy Services <daniel laser net>]

Max Hall wrote:

> 1500 W is pretty good for an inverter: it's enough to run, say, a 
> hairdryer
> which is a PIG. But I think it is insufficient. As for motors, you will
> certainly need something more like a circular saw motor than a drill to 
> run
> a mower blade, but I'll wager that even the circ saw is up to the task.

You may be right. I dont know, that's why I asked. However, I think
you're selling these motors short. Someone else on this list
guesstimated from his ammeter that his ET was drawing and additional
20-25 amps with the mower on. 25 amps x 36 volts = 900 watts for all
three motors. If I burn up a junkyard motor, what have I lost. A quick
connection plug and recepticle rated for 40 amps (at 24 volts) is going
to cost me $50. Plus the big-assed wire, plus the cost and hassel of
finding a 24v dc motor.

> Another tack: note that even a light-duty gas-powered mower employs 
> anywhere
> from 3 hp to 5 hp. I hp is about 750 W, so your maxed-out 1500 W mower 
> would
> offer about 2hp. That's on the light end of the spectrum for a 30" mower,
> let alone 36" or 48" blades.

C'mon Max, I think you know better than that. ICE ratings don't compare
to electric motors. An ICE is rated for it's maximum delivery point, at
250F, and 4500rpm a quarter inch from where it melts itself into
artwork. My three horse traction motor, with all the added weight of
batteries will run circles around any 12 or 15 horse gas tractor.
Anybody know the hp rating on an electric push mower?

> Why convert at all? Scrounge a 24vdc motor! or go with 36v (too late? 
> this
> thing is done?) because there's all kinds of 36v golfcart etc. etc.
> components out there. You'll drive yourself nuts trying to run things 
> off an
> inverter. Nuts, I say.

I've been called worse. Yes, it's a done deal. And I've run a sawzall,
1/2" drill, 3/8" drill, cordless drill charger, dremel tool, 4 1/2"
grinder, Lincoln arc welder, soldering iron, 7 1/2" circ saw, 11.5 amp
chain saw (for two straight days on the two toughest, gnarliest apple
trees what ever lived), 19" color TV and a 19 cu ft kenmore
refrigerator, all without a hiccup. Have you priced a 36v golf cart
motor. I have, $700, and it's a female coupling without a bearing
(designed to mate to the male transaxle).

Don't get me wrong, I appreciate all input here. But, once I find the
right mower deck, it's getting an ac mower, at least until it makes me
nuts (nuttier?). So, the question remains, how tough is it to retrofit
an ac motor with dynamic braking?

Dan