Papst Motor Question - Changing Rotational Speed by Changing Frequency

Some of the Papst motors have capacitance requirements for both 50 and 60Hz power supplies, these values may be extrapolated for
other frequencies. I would always recommend however that a 3 phase supply, as, for example, provided by the SG4 is a better solution.
 
Dar Ralph,
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Between 1980 and 1992, the Mechlabor SL 102 record player shown in the picture was driven by the Papst motor shown in the picture and the controller shown in the drawing.
I would like to make a copy of this record player that still works today. I would like to make speed control and display in a more modern design.
The motor is incredibly quiet because the ball bearing has been replaced with a sinter brass bearing. The shaft run out is less than 0.001 mm.
Bearing gap 0.002mm. So the mechanics are perfect.
Andrew
Like how that JFET in the schematic is drawn. Looks like a tube.
 
Godd schematic drawing from SL 102 motor controller&suplayer
 

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Theo pabst sync motors I have worked with all need 90 degrees between the coils. A state variable oscillator will get younthe correct phasing for free. Then two amp's and two transformers and you are on the air. I did this for Rockport a long time ago.
 
Are the phases at 120 degrees? All the motors I checked (30+ years ago) were 90 degrees. I discussed this with a motor engineer in the us and he validated the solution. You can check th ephase relationship with a scope. just spin the motor and look at the phase relationship.
There are other tricks like varying the drive levle with speed and using a current mode drive to reduce the effect of the harmonics in the less than perfect magnetic structure. It was a very interesting project some 35 years ago.
 
Very good

On the picture STM 610 komplet motor end controller power supply. Motor Papst on the picture
STM 610 studio recorder built over 8000 pcs
STM 310 built 3500 pcs
 

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Any idea about the Papst motor in the Elac 50H ? Is it a three phase motor running in single phase ?
Yes, most Papst motors in older turntables are 3 phase synchronous motors, with the odd exception being a 3 phase async. motor where there is a need for speed regulation by a mechanical or eddy current control; eg the replacement Papst motor designed for the Thorens TD124/II.
 
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You can't get three phases from single phase by using 2 capacitors; a single capacitor provides a phase shift for the second phase and Kirchoff's law provides the 3rd.
I had hoped to answer this question by means of the evidence from all of the motors in the picture I provided above, which, without exception, are 3 phase delta wound motors, but can be used, somewhat less efficiently, by means of a phase shift capacitor.
 
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Phase R to phase Y one capacitor, then phase Y to phase B second, equal capacitor.
This was used a lot, it is a valid method, the first cap causes a 120 degree phase shift. Second cap makes it 240.

Another method used is by specially wound transformers, and yet a third method is to wind the motor in that way, combined force and transformer coils.
Without proper details, it is hard to tell at times, particularly in small motors with potted windings.
 
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