modern day equivalent of electromechanical relays ?

Jul 28, 2008 2 Replies

I'm looking for the modern day equivalent of the old electromechanical relays. I want to route power/signals from something like a motor controller to one set of motors or another, so that I can use a single controller instead of a controller for each motor. I would like for the "channel" to remain set once it is selected. Preferably a single "channel" would consist of two wires. Relays would actually work OK for my application, but I don't want to eat up power by holding a switch open or closed for a length of time, plus I want something that might have, for example, one set of inputs and the ability to route that to outputs a,b,c, or d.



So what am I looking for these days ?



Thanks! JCDeen



A solid state relay following a motor controller may not work. DC solid state relays are polarized; they won't pass a DC voltage with reverse polarity. So you can't use them with a reversing motor controller. AC solid state relays usually are designed to switch as a sinusoidal waveform at the rated frequency (usually 60Hz) goes through zero. So they may not be happy with square-wave PWM motor drive power, and may refuse to turn on or off on a solid DC signal.

How much current do you need to handle? If it's 100mA, there are simple solutions. If it's 100A, it's harder.

John Nagle

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