Re: Microwave Oven Sync. Motors!

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Jim,

Many small AC gear motors (like clocks use) are synchronous.  Digikey sells 
these raw motors too.  The problem is they are too slow with the gear works 
and too low of power to do much with.  Since they are very low power 
impedance protected things, they don't have to worry about overheating or 
efficiency which is terrible in them from a percentage point of view.  We 
need to be able to turn big rotors fast so we need bigger motors.  I think 
John Freau say we need at least 1/10HP.  1/4HP 1800 RPM is perfect IMHO.

Cheers,

         Terry

At 06:58 PM 4/16/2004, you wrote:
>
>
>One more thing... I assume they use synchronous motors because they will 
>turn the other direction if stopped.  That way the turn table would spin 
>the other way if it got obstructed.  Another thing I found synchronous 
>motors in are those plastic "Disco Balls" that you see from time to time 
>in novelty stores.
>
>Regards - Jim Mitchell
>----- Original Message -----
>From: <mailto:Electrontube-at-sbcglobal-dot-net>Jim Mitchell
>To: <mailto:tesla-at-pupman-dot-com>Tesla list
>Sent: Friday, April 16, 2004 8:57 PM
>Subject: Microwave Oven Sync. Motors!
>
>Hello List,
>
>This may have been discussesd before but...
>
>I was taking apart a brand new "Galanz" brand 700w microwave (payed 40$ 
>for it ;-))  And I was removing the turn table motor when I noticed it 
>said SYNCHRONOUS MOTOR on it.  So I plugged it in,  and it spun slowly, 
>like 5 RPM.  I popped the case open and removed the gear assembly... I 
>then turned the motor on again.  This time It was spinning faster ~400 
>RPM?  It was also in sync with the line as the stick I had put on the 
>rotor was standing still in 5 different places.  The motor just had a coil 
>surrounding a rotor made of what seemed to be a magnet.  I doubt this 
>would have a lot of power but may work for a small propeller gap.  Sadly 
>mine stopped working after I got metal shavings stuck to the rotor and it 
>froze up.
>
>Regards - Jim Mitchell