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Topic: relay question |
Ron Victoria
From:
New Jersey, USA
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Posted 19 Sep 2013 3:41 pm |
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off topic, but maybe someone here can shed some light. I'm trying to fix a comb belt/disk sander for a fellow musician. He said it started sparking. I'm a retired shop teacher and some electrical background. The switch works properly. I noticed a relay. The power goes from the switch to the relay, and on to the motor. I plugged it in and get nothing. I don't know anything about relays. Is it likely the relay is shot? What does it do and are they expensive?
thanks, Ron |
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Craig Baker
From:
Eatonton, Georgia, USA - R.I.P.
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Posted 19 Sep 2013 4:15 pm Relay
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Ron,
A relay is simply a remote-controlled switch. It could have any number of connection possibilities, just like any switch. Single pole single throw / single pole double throw / double pole double throw etc. The contacts can become pitted or corroded, or the coil could be open. It could be used to dis-engage the starting capacitor, if one is used, and that would depend on the type of motor involved. Unless the sander is a very low-end throw-away model, your best bet may be to find a local motor shop. They would have the knowledge and parts to get it going.
All the best,
Best regards,
Craig Baker 706-485-8792
cmbakerelectronics@gmail.com
C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024 |
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Craig Schwartz
From:
McHenry IL
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Posted 19 Sep 2013 4:23 pm
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check the brushes (usually 2 of them by the air vent)
They spark when running
_________________
SO MANY LURES, SO LITTLE TIME.... |
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Ron Victoria
From:
New Jersey, USA
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Posted 19 Sep 2013 4:47 pm
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| Can I check for continuity on the relay out side or would this happen only show under power? I thought about the brushes but was looking to the relay first as I would have to remove the motor to get to the brushes. |
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Jerry Jones
From:
Franklin, Tenn.
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Posted 19 Sep 2013 5:31 pm
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If you've got AC to the motor, your centrifucal starter switch inside the motor housing is probably dirty. These motors used for sanders are notorious for failing due to dust contamination. If it's not that, it's your starter capacitor.... assuming it's not the switch.
Edited to add: The relay you are referring to may be a magnetic starter. The purpose of the starter is to prevent dangerous automatic machine restarts after there is an electrical interruption.
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Jerry Jones
Last edited by Jerry Jones on 19 Sep 2013 6:51 pm; edited 1 time in total |
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Craig Schwartz
From:
McHenry IL
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Posted 19 Sep 2013 5:51 pm
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theres one way to tell if its the cap, flip the switch on and spin it , if it continues to run ,its the cap.
HMM. That will bring back the sparking !
_________________
SO MANY LURES, SO LITTLE TIME.... |
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