Joe, I will get a shielded cable for the motor leads, and will ground
the cable, and will also add those filters. If I recall correctly, the
cables from the motors connected to the main terminal block, are not
that shielded, so if I shield the cables going from drives to terminal
block, it is only half the battle.
You can get flexible metal conduit (Greenfield) at Depot or Lowe's and
fish your motor (both spindle and servos) through the conduit to provide
shielding. It's cheap stuff, I just got a 25' roll of 1/2" FMC at Depot
for $10. They also have 3/8" size which may be better for the servo
Either will work. As will regular conduit in areas not requiring flexibility.
Nor is there any harm in doing both shielded wire and conduit, although there is
no electrical advantage either. Greenfield and conduit are immune to hot chips
melting a hole, though.
It's important to ground the shield where it passes through a shield wall, like
the motor case and the cabinet where the VFD lives. If the VFD isn't in a metal
cabinet, then ground the VFD end to the frame of the VFD.
For the record, this VFD ground is an extension of the safety (green/bare)
ground system, and not the neutral (white).
I'm suspicious of the VFD terminal block - it may be the power neutral, versus
the safety ground. The VFD frame ground (usually with green screw) is safe and
They also make line inductors that go between VFD and motor that reduce
interference by reducing the edge speed of the switched waveform that the motor
sees as a varying-frequency sine wave. However, such inductors are very big and
expensive, and very unlikely to be needed for such a small motor. (I have no
such thing on my VFDs.)
Joe, I bought those rings. I will shield the wires going to the big
terminal block from the drives, (and ground the shield) and would put
the rings on the wires going out of the terminal block to the motors.
Cheap enough to just try. One normally puts all three (or four) motor leads
through the same core, so the power-frequency magnetic fields largely cancel, to
avoid magnetic saturation of the ferrite. One can put multiple cores on the
same cable, one after another. Nor will anything bad or permanent happen if you
do put a single wire through a core, perhaps saturating the ferrite, so there is
no reason not to try everything.
What diameter of wire hole ? - need any ribbon ones - have them.
I think I have several like you mention from industrial equipment use.
I have a 3 phase, 50 amp RF line filter that I ran out of room to use.
Have AT NIC and modern NIC , various SIMS. e.g. HP printers and old pc's.
Let me know. Should be easy to get my hands on them.
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer
TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Originator & Charter Founder
IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
On 9/3/2010 10:22 AM, Ignoramus24760 wrote:
19:31:16 -0500 typed in rec.crafts.metalworking the following:
Ah, it sounds like you let the magical smoke out of the chip.
That's the real secret of electronic equipment, it really runs on
Just don't let the smoke catch fire. That's ...bad.
You might want to "add more fans" in order to increase airflow,
and hopefully cooling.
We will drink no whiskey before its nine.
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