I have a Papst Aussenlaufer on a TD124, this motor is definitely a 3 phase motor and I have been running it on 3 phase power from a Siemens Micromaster 420 with a sinewave reconstruction filter which also kills all of the PWM.
The very motor I own is featured in this thread (I bought it from Steve.) They're not worth the trouble unless you run them on 3 phase power and then they are. new project: TD124 with the Papst motor
This particular motor is an eddy current induction motor and speed is sensitive voltage, load and frequency.
These motors are almost all delta wound 3 phase motors as far as I know. You can trick them into running with reduced torque on single phase power. (There should be some details in my old thread, I seem to have lost all of the files I had.)
What sort of transformers are you using, what is the rated secondary voltage? I used EI types and was warned that toroids were difficult to drive. My 7294 based Chinese amps all oscillated and I added a zobel network at the output and a small (10 - 15uH) inductor in series with the output. That worked better, but I ended up with the Siemens.
The very motor I own is featured in this thread (I bought it from Steve.) They're not worth the trouble unless you run them on 3 phase power and then they are. new project: TD124 with the Papst motor
This particular motor is an eddy current induction motor and speed is sensitive voltage, load and frequency.
These motors are almost all delta wound 3 phase motors as far as I know. You can trick them into running with reduced torque on single phase power. (There should be some details in my old thread, I seem to have lost all of the files I had.)
What sort of transformers are you using, what is the rated secondary voltage? I used EI types and was warned that toroids were difficult to drive. My 7294 based Chinese amps all oscillated and I added a zobel network at the output and a small (10 - 15uH) inductor in series with the output. That worked better, but I ended up with the Siemens.
As far as I know Papst Aussenlaufer motors come in several variants, but fundamentally all 3 wire motors are wound as 3 phase delta.
These are many other types used in fans with odd and interesting characteristics
One interesting thing regarding the oem numbering system of motors starting with
901.... are synchronous, having a very high coercivity layer on the inside of the rotor (hard steel, vicalloy... ),
902 have an iron rotor and are not synchronous, as Kevinkr pointed out in his post above regarding the motor designed for the Thorens TD124.
Non-synchronous motors are also used in the reel motors of high-end Revox and Studer tape recorders, as is the capstan motor of any variable speed version.
Unfortunately many of these motors come only with numbers relating to their use, most, but not all will be synchronous🙂
These are many other types used in fans with odd and interesting characteristics
One interesting thing regarding the oem numbering system of motors starting with
901.... are synchronous, having a very high coercivity layer on the inside of the rotor (hard steel, vicalloy... ),
902 have an iron rotor and are not synchronous, as Kevinkr pointed out in his post above regarding the motor designed for the Thorens TD124.
Non-synchronous motors are also used in the reel motors of high-end Revox and Studer tape recorders, as is the capstan motor of any variable speed version.
Unfortunately many of these motors come only with numbers relating to their use, most, but not all will be synchronous🙂
Last edited:
Hi Kevin. Thanks for chiming in and linking the Thorens thread, which i have somehow missed. The very first 124 i heard came with an aftermarket Papst motor and much later i owned both a Papst and E50 tables. The acoustic noise of the Papst was quite audible but it did sound better than the E50.
Very amusing that the 3-phase argument is not new 🙂
During the course of this thread i sorted out the transformer selection. For such a power hungry motor step up ratio is critical: too low and the amps may get into clipping, too high and the reflected impedance drops below 4ohms. A ratio of about 10 seems perfect. Low resistance windings are also very desirable as the wasted power is significant.
The motor works perfectly well driven from a single phase and cap with the generator > low pass filter >7293 and step up transformer at the moment.
Very clean waveform at the motor coils and very stable speed. There was some weirdness with some dead area where frequency change would not cause a corresponding change in speed but this turned out to be due to a low supply voltage - about 70v. At 85v and above setting the speed is very smooth but the fan noise is not pleasant. Not a hint of oscillation in the amps and all consumed power is accounted for.
At this stage nothing explains why the 3-phase connection raises the power consumption 3 fold. I have already ordered and alternative higher power amplifier.
There is always the possibility a single amp works fine, but connecting the outputs of all 3 together introduces oscillation. I have not noticed it, but neither have i looked hard. If Kevin had had an issue using similar amps it does not seem too far fetched. The alternative amps will be class D.
These are the amps I used for my experiments
Search for
TPA3116 D2 100W on ebay, the exact ones are not listed ,they are very cheap, but seem to work fine
Search for
TPA3116 D2 100W on ebay, the exact ones are not listed ,they are very cheap, but seem to work fine
Last edited:
I'm an unretired electronics engineer. LOL Never have quite enough free time for everything. 😀
I confess I have never measured the power consumption of my motor. One of these days I probably should.
I confess I have never measured the power consumption of my motor. One of these days I probably should.
Question; I see no burden resistors on the amplifier outputs,nor any discussion of them, which in my experience are necessary to keep the amplifiers from overloading, as the dc resistance of the transformer windings are close to zero.
I have until recently been driving a pm synch motor with a 2 channel frequency generator on a laptop, using headphone out to a small stereo amp, which drives two step up transformers through 4 ohms resistance. No resistors, and the amp shuts down. 8ohms doesn't sound as 4, I assume because the amp then develops more voltage swing, , thus more cogging.
I have a Pabst motor, hysteresis synchronous, confirmed 3 phase delta. Don't have a 3 phase source worked out yes, read the reference to smoothing the output of a VFD with interest!
I have until recently been driving a pm synch motor with a 2 channel frequency generator on a laptop, using headphone out to a small stereo amp, which drives two step up transformers through 4 ohms resistance. No resistors, and the amp shuts down. 8ohms doesn't sound as 4, I assume because the amp then develops more voltage swing, , thus more cogging.
I have a Pabst motor, hysteresis synchronous, confirmed 3 phase delta. Don't have a 3 phase source worked out yes, read the reference to smoothing the output of a VFD with interest!
Have a look here:-
Optimally driving a (VPI) synchronous turntable motor
There's lots of info regarding successfully driving Papst 3 phase motors. I'm currently looking at using one of the large motors as used in a Studer A62 tape recorder, in conjunction with a platter exceeding 20Kg.
Optimally driving a (VPI) synchronous turntable motor
There's lots of info regarding successfully driving Papst 3 phase motors. I'm currently looking at using one of the large motors as used in a Studer A62 tape recorder, in conjunction with a platter exceeding 20Kg.
Thanks,looks familiar! I like your xfrmr mounting, pretty efficient! My transformers were 480/24V control transformers(motor was a Berger Lahr 120V). I used 4 1 ohm 10W resistors per phase/channel, which ran cold, no heat sink needed When I tried 1 8 ohm 10W resistor per phase, they ran quite warm; the sound was punchier, but had less 'space' and hf extension. Drove the spouse from the room! The set up was very sensitive to voltage level; 1 volt change could have similar, if lesser effects to the change in resistors(ended up around 71 V). My working conclusion is cogging pulses load the cantilever suspension, inhibiting cantilever movement and thus signal generation. A larger example of this effect is mis-adjusted anti-skate, or out of level ET2.
Currently trying out 2 BLDC set-ups, one 'frequency controlled' (the upper end ProJect/MMF motor pod available from Hifi Heaven), the other 'voltage controlled'( from Rek-O-Kut). Setting speed with voltage motor only involved adjusting a pot, the HZ motor required filing the pulley! Both are clearly superior to the pm/synch motor, but I find belt tension has significant effects ,i.e., the same 'punch' vs. 'space' trade off I noted previously, and I had noted the same effect with the pm/synch motor replacing old,stretched belt with new- I reduced voltage with the new belt(motor was fixed-BLDC motors are both in pods which can be shifted on a platform).
So, not totally "cog free"? Hysteresis may be the best solution. I also have tape deck motors in the queue, two Ashlands out of an Ampex. Good thing I just retired...
Currently trying out 2 BLDC set-ups, one 'frequency controlled' (the upper end ProJect/MMF motor pod available from Hifi Heaven), the other 'voltage controlled'( from Rek-O-Kut). Setting speed with voltage motor only involved adjusting a pot, the HZ motor required filing the pulley! Both are clearly superior to the pm/synch motor, but I find belt tension has significant effects ,i.e., the same 'punch' vs. 'space' trade off I noted previously, and I had noted the same effect with the pm/synch motor replacing old,stretched belt with new- I reduced voltage with the new belt(motor was fixed-BLDC motors are both in pods which can be shifted on a platform).
So, not totally "cog free"? Hysteresis may be the best solution. I also have tape deck motors in the queue, two Ashlands out of an Ampex. Good thing I just retired...