simulate motor starter (self holding relay) in EWB

Pandiani

Hi, guys, maybethis is not right place for asking this, but still I'll try
I have a problem, I can't simulate self holding relay in EWB 8.0 In version 5.0 I could
I wonder what is the problem and if anyone had similar experience?

Bruce Bates

Pandiani -

I can't help you with EWB as I'm not familiar with it, but perhaps the following will help as a general guide. In order to establish a holding circuit for a relay or contactor, you need one extra set of normally open contacts, over and above any you may be using now.

One (additional) wire goes from the V+ supply through one side of this extra N.O. contact, and a wire from the other side of that same N.O. contact goes to the V+ side of the coil. In order to provide a release ("STOP") for it, you would need to put a normally closed switch in series with that same circuit you just constructed, or alternatively, insert that N.C. "STOP" switch in series with the V+ line before anything else gets wired to it . That's really all there is to it.

Two additional notes. The existing "START" switch should be a momentary, normally open switch, and should be wired from V+ directly to the V+ side of the coil. Any "STOP" switch you may choose to implement should be momentary, normally closed, and be in series with the V+ line before anything else gets wired to it (wire it in nearest the V+ source).

Should you need them, any multiple "START" switches need to be wired in PARALLEL with one another. Any additional "STOP" switches need to be wired in SERIES with one another.

Regards,

Bruce Bates

Aristides Alvarez

Hello,

This thread was·moved from Stamps in Class to the Sandbox Forum.

Regards,

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Aristides Alvarez
Education and Technical Support Manager
aalvarez@parallax.com
Parallax, Inc. www.parallax.com