Re: [CAD_CAM_EDM_DRO] Servo braking resistor in series with motor armature

Henrik Olsson wrote:

>
> IIRC the new UHU-drive is going to be rated at 160V, 25A but it seems it
> won't be able to drive anything that a Gecko can't already
> handle.....putting a resistor in series cripples the performance of my
> motors, costs a lot of money and is a waste of power but right now there
> aren't that many S/D servo drives available that can be used for these
> motors (that doesn't cost $1000+) Aaargh.... :-(

I haven't tested my drives up to 160 V (I get a bit gun-shy with
these things) but I have delivered a number of systems at 108 V
and am confident they can go quite a bit higher, I'm using 200 V
transistors in them. The real kicker is that as the DC voltage
goes up, the rate of current rise goes up, too, and so the
overcurrent trip circuitry needs to respond faster. I think the
key is to change the single filter inductors to a pair of
smaller value in series to keep them out of saturation.

Anyway, my servo amps are rated to 20 A and have been proven on
a number of larger machine tools. They are not step/direction,
but I have a PWM controller for them, and a 4-axis system is
still well under $1000!

Jon