dodge78 94 #1 Posted March 7, 2014 Well most of the time. I started a new job after 11 yrs at a dealership of headaches. It pays less but the stress is almost nonexistent. My new job is at a surplus store. Here is the new job http://7riverssurplus.com/shopsite_sc/store/html/index.html Now to the part I don't like about it. There is a Black & Decker 10 inch bench grinder from about 1957. It was reported that it would trip the breaker in less than 1 minute. I figured the guy who tested it, plugged it into an extension cord to test it because it was to heavy to put on a bench. I plugged it directly into the wall outlet. It grumbled a little bit but spun up to speed in a reasonable amount of time. After about 2 1/2 minutes of run time, I could smell hot wires, and shut it off. I flipped it on its side and pulled off the cover and noticed it had been dropped and broke the side off of the base. It was welded back on and painted so it was not to noticeable by looking at the outside.The relay had been smashed at the same time. I pulled the relay off and straightened it out so it works as it should. While on its side, I started it again. This time, it would not move. I shut it off, gave it a spin and turned back on. It started right up this time. After more testing, I figure its the relay that is bad. The resistance on the coil side is very high. So what it boils down to is: where do you find a relay that is almost 60 years old? Its a Potter & Brumfield MS-4AY-240 3HP 240V 60HZ . I am falling in love with thing, I might have to own this grinder. tom Share this post Link to post Share on other sites
Save Old Iron 1,571 #2 Posted March 7, 2014 they are out there Tom https://www.google.com/search?q=3HP+240V+60HZ&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=rcs#channel=rcs&q=30+amp+contactor+relay&rls=org.mozilla:en-US:official You didn't mention it but I assume this a 220 VAC setup - possibly 3 phase? Grainger may be a real good place to start. http://www.grainger.com/tps/electrical_choosing_relays_motor_starters_contactors.pdf Share this post Link to post Share on other sites
shorts 182 #3 Posted March 7, 2014 (edited) any relay/contact set that has the same specs will work, 3HP 240V 60Hz., lots of the newer electrical components are dual rated for 50 or 60 Hz to be compatible with the grid in other countries The 3HP 240V designation indicates that you will need a 30amp 220/240V circuit to run the grinder under load Edited March 7, 2014 by shorts Share this post Link to post Share on other sites
