Replies

1. 
   jackiechan | Mar 07, 2003 06:47am | #1

   Tom,

   You might try McMaster-Carr (http://www.mcmaster-carr.com)  They carry almost anything you could ever want, and their customer service is top notch.

   Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

2. 
   Jamie_Buxton | Mar 07, 2003 08:22am | #2

   The switch is unreliable?  It might be that you're running more current through it than it is rated for; motor starting currents are very large.   My vacuum press came from the manufacturer with this problem.   I solved it by adding a power contactor relay to control the pump, so the vacuum switch only needs to handle the control current for the relay.

   If you'd rather not re-engineer your controller, http://www.joewoodworker.com/ offers a vacuum switch, but I have no experience with it to report.

   
   

   ---

   Edited 3/7/2003 12:27:36 AM ET by JAMIE_BUXTON

1. 
   TomMGTC | Mar 07, 2003 04:02pm | #3

   The switch is rated for the amount of current i am using it for. the problem apears to be the contacts sticking. The pump frequently continues to run after it has reached the set vacuum. If I tap the switch it will shut of and turn back on after the vacuum drops past the deadband. It may or may not shut off the next time. Problem is i have to be there to monitor it. I will check Mcmaster carr. I got the current switch at MSC. I will also give Joewoodworker a call and see what kind of reliability he has with the switches he sells.

   Thanks guysTom

1. 
   Jamie_Buxton | Mar 07, 2003 10:53pm | #4

   Many switches have a rating for the continous current they can handle.   The problem is that when a motor starts it can draw current which is much larger than when it is running.  Furthermore, because the motor is an inductive load, a momentary arc can form when the switch gets opened.  These two effects tend to pit the switch contacts, and can make them stick.   Power contactor relays are designed to handle motor loads, and survive this treatment.   Adding one to my vacuum press has made it much more reliable.

3. 
   JPGrout | Mar 08, 2003 06:14pm | #5

   I use this one and hav never had a bit of trouble with it My Vacuum pump is 3/4 hp and it handles the current fine

   http://www.surpluscenter.com/item.asp?UID=2003030809065200&catname=&qty=1&item=11-2080

   Joe