I have a simple motor start stop circuit, making a long story short the stop PB is located 1000's of feet away from the MCC bucket. I'm having some issues with voltage drop on the power coming back from the stop PB. I'm picking up size 4 starter. I can solve the problem if I use an interposing relay off the stop the button and use the interposing relay contact in the stop circuit. My question, is using a interposing relay on the stop circuit OK, if not where in the code. Are there any special considerations I need to look at? As always any help is greatly appreciated.
Motor stop / start circuit
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Cow
Senior Member
- Location
- Eastern Oregon
- Occupation
- Electrician
Sounds like a plan to me.:thumbsup:
Have a look at the Square D paper cited in https://forums.mikeholt.com/showthread.php?t=169020 for some good information. There was another recent thread on the issue as well, but I can't seem to find it. https://forums.mikeholt.com/showthread.php?t=173986
Last edited:
petersonra
Senior Member
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- Northern illinois
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- engineer
not a code issue IMO.
- Location
- San Francisco Bay Area, CA, USA
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- Electrical Engineer
...and done all the time.
Think about it, a lot of control schemes use what is called a Master Control Relay (MCR) in the E-stop circuit. So all the E-Stops were wired in series to the MCR coil, then contacts in the MCR are in series with the motor starter coil circuits. Slap any E-Stop, kill everything at once. You are doing the same thing, just with only one unit.
Go for it.
Good example
elevator hardwire safties are done this way
as long as fail safe, ie an open relay ckt results in shutdown
reclosing ckt does not start motor, need a reset or a start command
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