Richard Clark wrote:
On Thu, 11 Sep 2008 17:45:11 -0400, ml wrote:
previously i can say there was no chokes power went right into the
unit

today we installed the line filters they have some chokes


i noticed that line, in the manual, not really sure what it means
the power as supplied by con ed is rock solid as far as volts etc
power here is great

Hi Myles,

Industrial equipment is often rated in percent or per unit impedance.
http://en.wikipedia.org/wiki/Per-unit_system

For something like this, the impedance is probably mostly reactive. That
is, 1% impedance means a PF of about 0.99 (well, sqrt(1-.01^2).. that
is, you'd draw 1% reactive current.



I'm not sure what that specification line means either, but choking is
a standard term for reducing the influence of inductive kick,
something those motors are going to do aggressively and spread RF
trash throughout the spectrum.

However, in the context of motor controllers, solid state triacs can
also be quite noisy and inject trash into the line. This has nothing
to do with Consolidated Edison, except that they, too, could become
annoyed with noise. However, they have a large industrial customer
base that they serve, and they deal with it.


I would venture that there are no TRIACs in that controller. It's a
standard 3 phase IGBT based inverter drive. The default PWM frequency is
10 kHz, and you'll probably see significant harmonic content at
multiples of that, although CE compliance means that they've filtered a
fair amount out. There's recommendations on page 164 for line filters.
You could probably check with Magnetek for details on conducted
emissions with and without filters.