On 2009-09-02, GeoLane at PTD dot NET GeoLane wrote:


I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches
in a separate box would be a lot more convenient. What are typical
specs for a potentiometer for one of these?
RWL


Look in the wiring diagrams and it should show you what value the pot is
supposed to be.

Generally....0-5k...some are 0-10k, others are different.


Gunner


Thanks Gunner, Iggy, Don
I scanned through the manual looking for the wiring diagram and next
to the potentiometer it says "10k ?" I"m not sure why the "?" is
printed in the book but that's what it says. I looked at the on line
listing at Radio Shack - not too pricey, about $3. The only problem
is, they only list 0.5W potentiometers and Don had mentioned it ought
to be 2 Watts.

If the control voltage is 10 volts, then a 10k potentiometer would
dissipate 10v*10v/10000ohm = 0.01 watts. You do not need a 2 watt 10k pot.

I looked in the Mouser catalog and I spot two that would probably do
the job. One's a high precision single turn pot EUP-1400-10k for
$4.15. The other is listed as a 53 series industrial pot with a 25k
rotational life expectancy. 785-531C10k for $6.76 Both of these
handle 2 watts.

It looks like the control switches for my VFD should be momentary
switches.

You can always test that with a wire that has two bare ends. Just
touch two appropriate control contacts, while staying away from R,S,T
and U,V,W and other big screw terminals.

i
RWL