DC Motor Speed Control

[MTaha]

Hi,

I need to soft start a 1KW 48VDC Motor. I am thinking of using solid state relay with the V350 built in PWM function. I believe the use of SSR with DC motors is not recommended. Could anyone advice what hardware may I use?

[Joe Tauser]

You can do this, but you need a DC MOSFET SSR.  A regular one won't turn off, as the triacs in it are waiting for the supply to cross zero volts.  Which won't happen.

http://www.crydom.com/en/products/panel-mount/perfect-fit/dc-output/

Your motor will draw 21 amps, so get a 40 amp unit.  You'll need to mount it on a heatsink.

Joe T.