This is a generic Papst Motor, as opposed to a custom design. It was used in the Voyd Reference turntables after the B282 became obsolete. Large flywheel and being 3 of them it essentially provided 1.95 Joules of stored energy meaning the compliance of the belt between the platter and this energy store was the limiting factor. The Voyds with just a 0.8Kg platter could compete well with high mass designs because of this design approach. The stored motor energy is equivalent to a 29Kg (64lb) platter.
50Hz plots – not great and shows why we never used them at 50Hz/1500rpm. There is a ripple which is likely the thrust bearing mechanism. Interesting that reducing the speed removes this which would imply it is an eccentricity of the thrust ball bearing where at lower speeds the progression on the thrust pad is less pronounced.
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The next plots are at 37Hz (1110rpm) with an adjustable phase PSU – note the strong 100Hz commutation peak has gone
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These are the 25Hz plots which was the Voyd Reference operating point for 33rpm.
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And here is a plot with the 3D printed lightweight jig touching the frame – it shows that with some mass in the mounting and 25Hz operation, a satisfactory result.
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Speed Variation below – approx +/-0.5rpm variation per revolution.
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