Vaccum Pumps?

I think it might be William B Noble. Link to his site below.

billh

how fortuitous - I was just about to post my occasional "solicitation message" reminding the group that I exist, and here comes the perfect inquiry and an unsolcited referral - what could be better :-)

I have at this moment two 1/3 hp wobble piston pumps left, one three phase GAST vane pump (with a VFD if you want it that way), and a few other vane pumps - all the info is on my web page under vacuum pumps

And, I make inexpensive faceplates - welded ones - again the details and pricing are on my web page, but under faceplates (seems logical, no?). I started making them because I couldn't see paying $35 for a faceplate that would be used on a fixture, you too may have a similar aversion - I'm a great believer in functionality so while they are not beautiful works of art, polished to a high shine, they will hold your wood or fixture.

Hi Bill, I have a couple of questions that you may be able to answer:

1. What happens in a typical inverter VFD drive when the wire(s) connecting the speed control pot are broken? Does the motor shut down or run away or.....?

1. I am using a 2 cylinder, single-stage, fairly large, old refrigeration piston compressor as a vacuum pump. Apparently it was used many years ago on a farm to chill a large cement tank with water that the cans of fresh milk were placed in to cool quickly. I cleaned the valves etc and it pulls about 28" Hg and seems to be able to tolerate some leakage. Any (very) rough idea how this pump compares in pumping capacity with say a real vane vac pump?

Thanks, Billh

Usually it will assume zero speed.

Bill R

my best try at answers:

1. I tried this (inadvertently) - it depends on the VFD, I suppose - the one I tried it with just stopped. But it would depend on which wire broke - there are 3 wires to the pot - high (usually 10V) ground, and wiper. if the ground breaks, the wiper will go high and you will accel to max speed. if the high breaks, the wiper will pull to ground and you will decl to min speed. if the wiper breaks (or all break), it depends on the controller, but as I noted, mine stopped. If you are worried about this, you could set the max speed adjustment to a safe value.

1. impossible to tell without more data - the 1/3 hp pumps I sell are around