Re: SIngle phase ac motor question

On Mar 13, 11:14 am, "Phil Allison" <philalli...@xxxxxxxxxx> wrote:
"HardySpicer"



My understanding is that you must have a rotating magnet field to
drive an ac motor. Hence often a capacitor start system is used with a
second winding (for single phase) which is switched off once the motor
is started. Essentially this is a two-phase motor for starting.Am I
therefore wrong with the idea that a single phase on its own will not
rotate a motor since there is a single phase and one coil only after
the thing has started? How does a single phase give a rotating field?

** No Google where you live ????

Most commonly, single phase motors use a capacitor to shift phase and make
the field rotate.

Low powered ( sub 100 watt input ) examples often use a "shaded pole" to
achieve a similar result.

Plenty of good, basic AC motor stuff here:

http://www.allaboutcircuits.com/vol_2/chpt_13/10.html

..... Phil

I know that much. I was just asking as to whether without the
capacitor (we are back to single phase then and not simulated two-
phase) do we still have a rotating field.

Hardy
.

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