Soft Start For Electric Motor

[JoParticipant @jo]

Posted by jason udall on 15/05/2014 13:28:00:
Static and phase converters…as I understand produce pseudo two phase..and as such deliver less power than expected from your nominal 3phase motor.

Static converters start by creating two phases, the running of the motor creates the third phase. A rotary converter has a motor already fitted and that has already created the third phase. Both deliver full power when running.

Jason: May I suggest you stop your motor before going directly from forward to reverse, if you want the motor to last. If you use a coventry die head to cut your threads you can, if you must, go in full speed and no backing out is necessary with all its risks of swarf getting trapped and damaging the threads.

Jo

[JasonBModerator @jasonb]

Motor does stop as you have to go Fwd-0-Rev Though its quicker to press stop then select rev and start as the Back EMF braking stops the chuck faster than letting it run free down to a stop in zero before selcting reverse.

Never found swarf damage to be a problem whether backing out under power or by hand before I had the variable.

Edited By JasonB on 15/05/2014 14:59:13

[blowlampParticipant @blowlamp]

Ditto what Jason said.

Not using the variable speed function of a VFD is a massive loss of utility in my book. I still use the gearbox of course, but being able to alter the RPM on the fly is brilliant for helping in all sorts of ways, one of which is tuning out chatter, especially when using boring tools.

Martin.

[Author]

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