Re: [CAD_CAM_EDM_DRO] speed control of 3/4 hp synchronous motor

"Multi-Volti Devices (Murray)" wrote:

> Hello:
>
> Is it possible to vary the speed of an off the shelf 3/4 hp synchronous
> motor?
>
> >From school, I vaguely recall a frequency-dependent 'slip' issue that
> prevented this from being easily done.

There is no slip on a synchronous motor. Induction motors use slip to
excite the rotor field.

> Is a VFD the answer? Is so, is this a small motor for a VFD? If yes, has
> anyone ever seen a DIY project for this?

It takes fairly elaborate tricks to start a synchronous motor from a
constant frequency line. varying the speed by varying the frequency and
voltage should work fine, once you get it started.

Are you sure this is a synchronous motor? I don't think most motor
manufacturers consider any 3/4 Hp synchronous motor as an off the shelf
item.

Jon