60hz synchronous motor on 50hz?

[paulj]

It's a success, I just started the engine using only two of the three wires.

Without capacitor it starts quite easily but not every time, the stator remains lukewarm without more, on the other hand as I expected, its speed of rotation has been modified.

as evidenced by this picture which was taken under a fluorescent tube at a shutter time of 1/50 s



the position of the axis (golden color) remains constant it is located between 9h and 3h I therefore deduce that this synchronous motor rotating at 3600 rpm in 60 hz, turns at about 3000 rpm in 50 hz.

regardless of the starting position of the rotor, each time the motor is started, the axis always seems synchronized with the frequency of the current, moreover the motor can even start at 50v 80v and even 150 volts (spot test) and this does not even change its speed of rotation.

For the history of the capacitor, I will therefore wait a bit because for the moment helping it to start is not a problem.

CONCLUSION, The 60 Hz synchronous motors are compatible in 50 Hz and are therefore perfectly suited to rotary spark gaps.

[klugesmith]

Applause!   Nice stroboscopic picture, without un-necessary effort.  I bet it would not work if the fluorescent light had modern "electronic" ballast.

Let's see if this link works. Fancy line-synchronized LED stroboscope, primitive modification of a shaded-pole induction motor.
https://www.flickr.com/photos/r_k_f/3688448113

[paulj]

I actually tested on a compact fluorescent lamp which has a transitor ballast, it does not work at all

The strobe effect is even more visible with a discharge lamp.
however, i think the motor draws a little more current in 50hz

Did you make the video? it's fun when the motor is braked it stays synchronous but the mark is not in the same location so it is a hysteresis synchronous motor

[klugesmith]

It's not a hysteresis synchronous motor (though my collection includes that kind).

This one has an ordinary induction rotor with two flat places filed onto it.  I guess that makes it a "reluctance synchronous motor". (It would probably work better if the flats were bigger.)
In synchronous operation it has two stable rotation phase angles, 180 degrees apart.
We see both in the video.
I think that behavior would be fine in a SRSG, if the rotor has a conducting bar across whole diameter, and two fixed electrodes 180 degrees apart.