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Topic: Triac vs Relay (Read 1 time) previous topic - next topic


Hi There!

I want to control (on and off) 1.5 HP, 220VAC motor from Arduino.  I am thinking of controlling the motor by building a solid state relay using MOC 3021 and triac BTA16.  Is this the best approach? or using a relay is the simple and better option?  Need to know any advantages and disadvantages of both the approaches.  Any suggestions are welcome.  Thanks in advance.


Best is to buy a ready-made random turn-on SSR, but they are expensive compared to making your own. If you use a mechanical relay, you should connect a snubber network across the contacts to control arcing. You may need to use a snubber network with the home-made SSR too.
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Induction motors are a nearly pure inductive load (tricky for triacs) - do you have specs / datasheet for the motor?
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At that power it's time to look for properly sized 'motor starters', which is just a fancy name for a electromechanical relay built for such service.



Thanks all for your responses.  I have decided to go with 10 Amps relay.  For the snubber network, If have one capacitor of 10nf/680V and one resistor 39R in series across the relay switching terminals, is that sufficient?

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