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Discussion Starter #1
--- Rod Hower <[email protected]> wrote:
> Jim,
>
> Let me know what you find out on these AC motors.
> Sounds like they tried to over-compensate cost
> reduction on the motor to make up for the higher
> electronics cost?
>
> Thanks,
> Rod
> P.S. I have nice 9" frame size AC motor for a 5,000
> lb
> forklift, wound for 24Vdc. It might make a nice
> 'go-cart' motor :). I still need to throw together
> a
> control though.

Hey Rod

All of the motors I've seen from Winco have been
shaft, bearing, and or general clean up issues and not
anything in the windings (then again the same can be
said for the DC motors I do.

The BT models I've been getting from Winco Foods are
made by Danaher (Czech Republic) and in fact are good
motors from what I can tell so far, minus the abuse my
customers dish out 8^)

The data tag on the Drive unit says that it's a 3~87
Hz, 34 volt 174 amp, 7.5 KW at 2500 RPM's.

One of the biggest issues that I see is that these
Danaher motor use an encoder bearing on one end that
runs 600.00 bucks if it needs replacing 8^o IMO
that's a pretty costly bearing and in fact costs more
than most of my total invoices for full DC motor
repairs. Although the winding aspects are not the
problem with these units the fact that I'm already
seeing them do to these other issues tells me that
there is nothing that someone can design that another
person can't beat the crap out of 8^o

I'll grab some pics before I get these two I have in
shop back out, and I'll post them at the site when I
get a minute.

BTW, there's nothing like an old fashioned DC brushed
motor that any general controller can make run 8^)

Cya
Jim Husted
Hi-Torque Electric



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Discussion Starter #2
>One of the biggest issues that I see is that these
>Danaher motor use an encoder bearing on one end that
>runs 600.00 bucks if it needs replacing 8^o IMO
>that's a pretty costly bearing and in fact costs more
>than most of my total invoices for full DC motor

That encoder bearing is a problem in a lot of places.
I heard one go out on a dynamometer controller one
time. It was a motoring dyno (DC brushed, actually)
and went full-speed when it lost the encoder signal.
The 'crunch' as it took out a rather large diesel
ICE (the engine under test) was impressive. Those
heavy-duty truck engines were not designed to spin
at 6000 RPM!!!

In ICE applications, we also use an encoder on the
crankshaft, but it looks very much like the encoder
on the Siemens AC motors. Fewer teeth, and we use the
motor shaft's own bearings for support. Those things
are really quite reliable. The software is somewhat
tricky to get engine position by time interpolation
but it's not rocket science. ICE controllers have
been doing it since the 1970's. With a 60-tooth
mask, you get plenty of resolution down to maybe
20 RPM. Not quite good enough for servo positioning
but fine for ICE. We go for a timing accuracy of 1/4
crank degree or better. I would think that such
resolution would be fine for EV or forklift motors.

Sounds like there are a lot of idiot designers out
there.... I try not to be one most of the time.

-Dale
 
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