RE: Syncing Motors (was Re: new coil specs)

Pictures to go with Reinhard's excellent directions can be found at
http://fp2.hughes-dot-net/brianb/download.htm (you want the file called


-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Friday, November 05, 1999 7:13 AM
To: tesla-at-pupman-dot-com
Subject: Syncing Motors (was Re: new coil specs)

Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net> 

Hi Stan, Grayson,

Comments interspersed.

> And the modification:

Whoah! Stop. This may be true for your motor, but cannot be
universally true. The number of flats depend on the motor
speed. For a 3450 (modified: 3600) rpm motor you only need
two flats. The depth of the flats is more or less given by design.
You will need to measure the exact width of the dead poles
(center to center).These are the poles through which ONLY the
start windings or NO windings at all run.

Using a mill (for best balancing) you want to mill 4 flats at 90°
(or 2 at 180° for 3600 rpm motors) that are exactly as wide as
these dead poles are. Since you are milling a flat of given width
on a round surface, the depth of the cut is automatically pre-
defined. More material is removed from the center of the flat
and less from the left/right ends of flat. What you are essentially
doing is creating "physical" poles, which will sync to the magnetic
field that the mains create in the run windings.

There will no longer be any slip between mains frequency and
rotational speed, which is why these motors donīt have a great
amount of torque, once they achieve their "new" top speed.

Coiler greets from Germany,