Hi,
Glad I could join up. After a bit of searching in the archives, it looks like
the members here know how to match up motors with controllers.
Since I started thinking about building my own go-kart - really just an
off-road buggy for my son to scoot around with - I've been wondering if the
left-over motors from my previous projects would be suitable.
I have what you could call a BLDC (brushless DC) motor in my garage, but it
comes from an unusual source:
I converted it from a 7.5HP induction motor, by turning the rotor down on a
lathe, and installing permanent magnets on it. I left the winding mostly
unchanged, save for extending all phase wires out separately. Why? I meant it
to be a 3-phase alternator for a wind turbine. In the end, I did not use this
one for the wind turbine project, I did a smaller motor conversion, better
suited to my needs and less heavy on the tower. For anyone who wants to see
details on that project, and inside my motor conversions, look at this www dot
sparweb dot ca.
The motor in question is the converted Toshiba that I show on my projects
webpage. I did a number of run-up tests using a lathe to determine its
potential as a generator (which is good). Perhaps they are of some use in
determining its suitability as an EV drive motor. Of course, if the original
induction motor would have been better for an EV, the irony would not be lost
on me! I did not have an EV in mind at the time. Really my only problem is
having exceeded my practical limits with the size of wind turbine that I can
mate up with this generator, so I'm consindering other uses.
It would be most convenient if I could equip the go-kart with a set of four
6-volt golf-cart batteries, so I can tie it into my existing off-grid 24V
battery bank. Since a go-kart is just for recreational use (and maybe a farm
runabout if I put a toolbox on the back) I'm not too concerned about endurance.
#1 goal is fun. #2 is to teach my kid some things. #3 is for all the work on
that motor not to go to waste.
I spent some time looking at the datasheets and installation manuals for Kelly
motor controllers. Obviously they are written for installers using
"off-the-shelf" motors. The wiring looks straightforward enough, but I've read
in your archives that the harmonics are very important. I can't use an
induction motor VSD to do this kind of thing. There are controllers specific
to BLDC motors that I must use. At this time I don't have any hall sensors
built into my converted motor, but it could be done, if it's needed. The
original motor windings are rated for 240V/480V, but as I said, I'd rather
operate it from 24 Volt batteries, so that it can recharge from wind & solar.
Do these motor controllers "step-up" the DC from battery source to a higher
output voltage?
The converted Toshiba BLDC motor weighs about 200 pounds. I expect the battery
bank will be at least another 200, one driver (no pax seat) requires another
200 pounds, and I roughly estimate the welded steel framework, driveline, and
equipment to demand another 300 pounds. Roundly estimating 1000 pounds machine
when complete. A differential and disk brakes will be necessary... I won't be
winning any land speed records.
So my questions are:
Am I starting off on the wrong foot with this motor?
Will a typical BLDC motor controller be able to drive this motor without
burning up?
Do the motor controllers require hall-sensors to work properly?
If the odd features of this motor make it a bad candidate, then so be
it.
I'm still interested enough in making an EV go-kart, and getting my
hands on old induction motors is not hard.
Thanks to anyone who can help.
Steven Fahey
www.sparweb.ca
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