Synchronous motor

[kd6cji]

Put a hub and a 15" disk on the motor today and found out that the motor not always reach synchronous speed, sometimes it takes 3-4 times (on-off) before motor locks to mains frequency. I am not sure what is the reason. I don't think that it is too much load... I know that there are different kind of synchronous motors, this particular one is labeled as "reaction synchronous motor". Could not find any useful information what does it mean.

[MarkLebois]

I came accross a very interesting website with more info on this product: http://www.directindustry.com/industria ... 60998.html

I only allowed this post as it is useful (maybe) to us. If it generates spam or other crap let us know and that will be the end of it... (SA)..

Steve A.

[Ralph]

A number of decades ago I was building a fax recorder for weather satellite use. I counted a TTL crystal oscillator with a divider chain to get 60 Hz, ran it through a filter to generate a sine wave, and used the signal to drive a high-power audio amplifier module driving the 12V side of a hefty power transformer. The 115V windings drove the synchronous motor. Worked every time and was duplicated dozens of times by other enthusiasts.

Ralph

[Klaas Robers]

Sergei, it is because of the rotation mass of the disc that the synchronous motor is no more self starting. The best way to overcome this problem is connecting a small DC motor to the same shaft, or with a hub and a rubber band, which brings the disc into rotation and then switch on the synchronous motor. Then the synchronous motor is acting more or less as a synchronisation wheel.
However, a synchronous motor driving a Nipkow disc always shows some hunting. I have seen that frequently in the Nipkow discs driven by a bike dynamo (Dutch system). This is because the rotating magnet in the rotating magnetic field is a not damped system. A synchronous motor to drive a Nipkow disc, is seen by many people as THE solution, in reality it isn't. I have the feeling that with a DC motor running along with it, the hunting problem is much less. Then the synchronous motor may do with very little AC power.