Re: SSR or mechanical relay to turn on spindle?
Mechanical relays should not be noisy. the pulse from coil switching can be defeated with a diode (DC coil) or R/C snubber for AC coil.
The SSR should also work just as well.
The second option does not appear to be a mechanical relay?
You will experience much more EMI from the motor itself than any relay.
They are Universal motors.
CNC, Mechatronics Integration and Custom Machine Design
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