[TowerTalk] SteppIR cable capacitance (was: SteppIR problem)

[Jim Lux]

At 11:07 AM 6/11/2007, Jim Brown wrote:
>On Mon, 11 Jun 2007 12:23:32 -0400, Dick Green wrote:
>
> >There are lighting suppressors at the base of my tower and the side of the
> >house, which are separated by about 225' of cable. The suppressors are K5FD
> >SP12 Surge Protectors (see http://k5fd.com/surge.html.) As you can see from
> >the picture, for each wire in the cable, the two suppressors add four MOVs
> >and two .1uf capacitors in parallel (total of .4uf for the caps), plus two
> >ferrite filter chokes and two 5A fuses in series.


What voltage MOVs are you using (50VAC standard units? or the 35VAC units)

How much voltage are they seeing? you've got 1000 ft of series cable, 
1 conductor out + 1 conductor back, on top of the impedance of the 
stepper.  You might well be pretty close to the 30 odd volt output of 
the power supply just to keep the motor current up.  Put some x2 
inductive transients from the motor drive..