Re: [CAD_CAM_EDM_DRO] VSD QUESTION

john_glynn57 wrote:

>I WANT TO USE A TOSHIBA VSD TO CONTROL THE SPEED ON A SINGLE PHASE
>ROUTER MOTOR. THE VSD IS RATED AT 1.5KW BUT HAS A 3 PHASE OUTPUT AND I
>NEED TO DRIVE A 1.6KW SINGLE PHASE MOTOR BUT AS I WILL BE REDUCING THE
>FREQUENCY TO 50% TO GET THE SPEED THAT IS REQUIRED. I GUESS I SHOULD
>BE OK BUT AM INTERESTED TO KNOW IF ANYONE HAS EXPERIENCED THIS ALREADY.
>
>

You can't do this. Single-phase motors have a centrifugal switch that
cuts out
at about 80% of speed. If the VFD would run it, which is doubtful, you
would
have to get it up to 80% to drop out the starting switch, then take it back
to 50%. A 1.5 KW VFD would not drive a 1.6 KW single-phase motor, as the
line currents on the single phase would be way higher than the currents the
VFD was designed for. The transient when the starting swich cut out could
pop the transistors in the VFD.

Are you sure the router motor is even an induction motor? Most routers
other than Danly/Onsrud and similar 5+ Hp are universal motors, with
commutators. If this router is other than 3500 RPM at 60 Hz, it is almost
certainly a universal motor, or possibly a DC motor with rectifier.

If you have a warranty on that VFD, you won't anymore after you hook it
to this router.

Jon