On Sun, 20 Mar 2005 16:34:38 -0600, Wayne
wrote:

Hi,

I want to mount a VFD over the headstock of my lathe,
on the wall. This VFD comes with 1/2 knockouts so I
can cable directly to the VFD. My question is this
a safe place to mount the VFD as far as getting
splattered by any oil from the lathe?
VFD is rated @ IP20 (which I believe is about nothing).

Is there any RF issues that I should be concerned
about that makes mounting the VFD in an enclosure
desirable? I would assume the motor radiates more
noise than VFD would.

If I can mount it there without an enclosure,
then I don't need to remote the display.

Picture in the dropbox:
http://www.metalworking.com/dropbox/VFD_placement.jpg

Thanks,
Wayne D.
Greetings Wayne,
VFDs work by switching on and off rapidly. This creates lots of RF
noise. Two machines in my shop have big DC spindles drives. These
rectify (ie change AC to DC) the 230 3 phase input and chop up the
output to change the speed of the spindle. So they are similar in
operation to VFDs. They are really noisy in the AM band. Placed any
closer than about 20 feet an AM radio put out a really annoying
squeal.If mounting in a VFD encloser you will need to be sure it will
get enough cooling. The VFD I have says somewhere in the manual that
it needs a certain amount of cooling and there is a way to figure out
how much air flow is needed to achieve a certain amount of cooling
based on ambient air temp. Can you place some kind of shield in front
of it? I'm picturing a piece of sheet metal 6 inches wider and several
inches longer. Then it could be bent at an angle and screwed to the
wall such that it covers the top, bottom and front while leaving the
sides open. There would be a few inches clearance between the front,
top, and bottom of the VFD and the piece of sheet metal. The sheet
metal would be bent so that when attached to the wall it slopes at the
top so any chips that fall on it will slide off. BTW, there is no 3
phase to my shop so I make it with a rotary phase converter (RPC)
Three machines in the shop need good 60 hertz 3 phase input to make
the servo drives and/or spindle drives work. But all the smaller
machines are 1 HP or less and don't have CNC controls. Since the big
RPC draws about 1500 watts just idling I'm going to start putting VFDs
on the smaller machines and only turn on the RPC when it's needed. I
think they are a great invention and wish they were cheaper when I was
first wiring the shop 8 years ago.
Cheers,
Eric