the home of the turntable

Papst Aussenlaufer Motor Controller

radio, tape, stands and accessories

Papst Aussenlaufer Motor Controller

Postby lxcount » 05 Oct 2011 19:45

Hello,
I am an avid turntable freak. It seems all my favorite classic tables have the same Papst "Aussenlaufer" Motor. I have searched for definitive info on the working voltages of this motor to no avail. This is a post on electronic 3-phase power controllers.

some Background:
My Vinyl experience started young, around the house growing up we always had a Thorens TD-124 mk1 with the Papst motor. At some point I wanted my own turntable, and after various low-end free tables found on the street, I learned online about the Fairchild 412, and became obsessed with it. After reading about the tube electronic motor controller 412-4, I knew I wanted to build a 3-phase supply for my 412 and the Thorens. After getting an Empire 208, plus digging out my fathers older Rek-o-Kut N-33H, to my surprise both also had the Papst "aussenlaufer", it became even more of an obsession. So now I have 4 tables with the same Papst motor.

In the past year or two I have read of people (on this forum) using a Siemens micromaster 420 to run an EMT table outside of it's country of origin, plus gaining 3-phase power and adjustable speed control.

Well, being a cheapskate I bought the first 3-phase motor controller I could find on *bay. Looking at the specs written on the back I assumed I could variac the power from 0-220v, but the controller I found seems fixed at 220v output. Not wanting to damage one of my motors I first tried the lightbulb trick, for 3-phase I wired up 3 lightbulb, each in series with a phase, and voltmeters hooked up everywhere to measure voltage. Well, the table spun up fine, but bulbs did not light and voltage shot straight up to 220, so I cut power immediately, afraid to damage anything.

Than I remembered something in Fairchild 412-4 schematic and looked it up, low and behold the voltage changes from 150v-450v!!!, 150v at 16rpm to 450v at 78. It states:

Another interesting fact is that as the frequency of the current is increased the reactance of the motor rises and hence the voltage applied to it must be increased to put the same current through the motor. For this reason, the switch also changes the output voltage. When operating at 16 rpm the applied voltage is 150 whereas on 78 rpm it is 450. This is accomplished by selecting an appropriate tap on the output transformer secondary...


There is also a chart with impedance of the taps for different speeds, so the other voltages can be calculated.

Primary impedance: 4500 ohm
Secondary impedance:
16 2/3: 600 ohm
33 1/3: 900 ohm
45 : 1125 ohm
78 : 4500 ohm - 1:1 tap


It is stated in the same article that even if you buy a 412 without electronic speed control, you can add the motor controller in the future, telling me the Papst motor in my Fairchild might not mind taking 220v, and maybe needs even higher voltages for 78rpm operation. (btw, anyone notice the last 412 sold on *bay appeared to NOT have the Papst motor, never saw that before, seemed to be a late model...)

So to get down to my main question,

Do you think possibly all the classic Papst "aussenlaufers" are equal?

They sure look the same....., maybe the only difference between the European and American models is the spindle size? I am fairly certain the motor in my Fairchild will take it, but I really don't want to hurt it. I am of course interested in running the Empire 208, Rek-o-Kut and Thorens with the same controller, or possibly other HV (120vac+) 3-phase motors.

Does anyone have more experience with 3-phase power controllers with the older Papst motors?

Any real world experience with the Siemens micromaster or other 3-phase controllers would be helpful.

Thanks, Alexander

ref: Fairchild 412-4 Article http://img196.imageshack.us/gal.php?g=fair412edscand.jpg
lxcount
 
Posts: 4
Joined: 11 Feb 2010 02:56
Location: nyc

Re: Papst Aussenlaufer Motor Controller

Postby Coffee Phil » 06 Oct 2011 08:10

Hi Alexander,

I am soon to be the recipant of a Rek-O-Kut Rondine 2 turntable which I think has a Pabst external rotor hystereses motor. It may be the same as your's. Are you sure it is a three phase motor? I think two phase motors for turntables are more common.

It is true that you want to increase voltage with increasing speed however changing the frequency is the bigger deal.

I remember the Fairchild from back in the day. I saw it in magazines, never an actual one. I looked up the schemo which you linked and sure enough the Fairchild shows a three phase motor. The schemo near the connector is fairly convoluted and I am too much in the need of sleep to sort it out. I will look at it again to redraw it.

The Fairchild variable frequency drive should give some inspiration and that triode connected amp is probably a good Hi-Fi amp but seems overkill for driving a motor. Also I'm not real fond of the death trap power supply. I think we can emulate the Fairchild variable frequency drive with some car audio power amp chips connected in the BTL configuration powered by a switcher for safety and AC to DC conversion. The output of the solid state amp can be stepped up with a 60 Hz transformer.

Since I will want 33 1/3, 45, 78, and 80 RPM on the Rondine 2 I think we will be comparing notes.

Phil
Coffee Phil
long player
long player
 
Posts: 2244
Images: 174
Joined: 20 Sep 2008 08:22
Location: California

United States of America

Re: Papst Aussenlaufer Motor Controller

Postby Steerpike_jhb » 06 Oct 2011 19:38

All the Papbst induction motors I've seen, albeit from tape recorders, are 3-phase, delta wired. These are also all hysteresis synchronous motors so they will not change speed with voltage.
Any system that varies the voltage to achieve motor speed will need some kind of velocity sensor and servo feedback system to get really accurate control.
The three phase motors can be run quite happily from a single phase by using a phase-shift capacitor.
User avatar
Steerpike_jhb
long player
long player
contributor
 
Posts: 1435
Images: 56
Joined: 28 Mar 2004 00:36
Location: Transvaal / South Africa

Re: Papst Aussenlaufer Motor Controller

Postby lxcount » 06 Oct 2011 21:03

Ah yes, Revox tape recorders and I am sure others use Papst 3-phase motors. I should take a close look at what is done inside the revox's.

The Papst Aussenlaufer is indeed Delta wired (3 wires for Delta, versus 4 for Y-wiring) in my Fairchild 412, Thorens td-124 (early models don't have it,) Empire 208, Rek-o-kut N33H (and I think all rek-o-kuts with Papst motors), my Gray table, and many others.

I have been using my VPI SDS to control all of these tables, but I know they should become quieter with true 3-phase power. I am trying to avoid/remove the phase-shift capacitor, though if empirical testing determines the capacitor to be equal to a true 3-phase supply, I would use it. Then only a 1-phase supply would be needed.

The system I described from the Fairchild 412-4 actually changes both the Voltage and Frequency, making it somewhat unique, at least in the range of voltage used.

The VPI SDS starts at 110v for maximum torque, than drops to ~72 volts at 33 1/3, or ~85v for 45, which indicates the need for possibly more torque at higher speeds even with the modern motor chosen.

I still wonder if putting 220v into a Papst aussenlaufer labeled 120v will damage it? Are they possibly durable enough to take 450v at 120hz or higher? or should I not make generalization on all Papst motors with a similar appearance externally?

I do not intend to use any kind of servo feedback or sensors as I feel this is unnecessary with these motors. Tuning the frequency should be enough as with all synchronous motors, just wanted to put out there that the earliest electronic motor controller, and the only official one from any major manufac. using these motors in the 50's/60's changes voltage and frequency.

I have seen written the papst aussenlaufers speed is 97% mains frequency, 2-3% torque load and <1% drive voltage

I hope we can develop a modern 3-phase motor controller for these old tables, utilizing a crystal and modern amp, possibly toroids are wideband enough to go down to ~30hz, not sure a 60hz transformer would have response that low.

Phil, definitely will help and stay in correspondence, I feel there is not enough information on this subject for the DIY phonophile.

Have you seen mark kelly's article on the subject?
http://www.clarisonus.com/blog/?p=92
http://www.clarisonus.com/blog/?p=96

He uses 3 audio amps, plus a 9v+9v - 120v transformer to get up to the needed voltage. Should be easy to implement, just need 3 perfectly 1/3-phase shifted sine wave, 3 amps, and 3 decent transformers of the right step-up ratio

I am thinking a DDS (direct digital synthesis) might be ideal as this would allow very fine tuning of frequency, but maybe a synchronous approach with individual clocks for each speed, with fine tuning through changing voltage to the crystal, (would warrant use of a VCXO)

I am also planning a 3-phase supply specifically for Hard drive motors (either delta or Y wired), but this is for either a DIY turntable or upgrading DC drive turntables, as I would prefer to leave these classic tables untouched.
-Alex
lxcount
 
Posts: 4
Joined: 11 Feb 2010 02:56
Location: nyc

Re: Papst Aussenlaufer Motor Controller

Postby lxcount » 06 Oct 2011 22:03

BTW, to test if a motor with 3 leads is 2 or 3 phase is to check impedance between the leads, if the resistance is equal every way it's a 3-phase, otherwise it is probably a 2-phase.
-alex
lxcount
 
Posts: 4
Joined: 11 Feb 2010 02:56
Location: nyc

correction

Postby lxcount » 07 Oct 2011 06:29

correction: the Papst 'aussenlaufer' was never sold with the Thorens td-124, but sold as a replacement part when the original motor became unavailable.
lxcount
 
Posts: 4
Joined: 11 Feb 2010 02:56
Location: nyc

Re: Papst Aussenlaufer Motor Controller

Postby Coffee Phil » 08 Oct 2011 06:30

The part of the Rondine with the motor has not arrived yet. I am itching to see it to determine if it is two phase or three phase. Also I am pretty sure it is hystereses synchronous but I will check. Apparently these motors can be hystereses or eddy current motors as supplied as replacements for the Thorens motors. It appears that the motor Mark Kelly is working with is the eddy current type.

Mark Kelly used a three channel amp for his three phase motor and that is the most obvious approach, but I think a two channel amp can be used also with a delta connected motor. Note the Fairchild electronics used one phase shift cap for each speed (essentially two phase drive). With a two phase motor you would need 90 degrees between the two phases. With the delta three phase motor with one lead common I think you would use 120 degrees between the other two leads.
I need to review the delta - Y conversion formulas. It has been a very long time.

If you are using a 60 Hz transformer at its ratings for 33 1/3 it should be fine at 16 2/3 as the voltage will be one half so the flux density should be similar to that at its rated voltage at 60 Hz. By the same reasoning at the higher voltages required for the higher speeds the frequency is also higher so the flux density stays the same.

Phil

lxcount wrote:Ah yes, Revox tape recorders and I am sure others use Papst 3-phase motors. I should take a close look at what is done inside the revox's.

The Papst Aussenlaufer is indeed Delta wired (3 wires for Delta, versus 4 for Y-wiring) in my Fairchild 412, Thorens td-124 (early models don't have it,) Empire 208, Rek-o-kut N33H (and I think all rek-o-kuts with Papst motors), my Gray table, and many others.

I have been using my VPI SDS to control all of these tables, but I know they should become quieter with true 3-phase power. I am trying to avoid/remove the phase-shift capacitor, though if empirical testing determines the capacitor to be equal to a true 3-phase supply, I would use it. Then only a 1-phase supply would be needed.

The system I described from the Fairchild 412-4 actually changes both the Voltage and Frequency, making it somewhat unique, at least in the range of voltage used.

The VPI SDS starts at 110v for maximum torque, than drops to ~72 volts at 33 1/3, or ~85v for 45, which indicates the need for possibly more torque at higher speeds even with the modern motor chosen.

I still wonder if putting 220v into a Papst aussenlaufer labeled 120v will damage it? Are they possibly durable enough to take 450v at 120hz or higher? or should I not make generalization on all Papst motors with a similar appearance externally?

I do not intend to use any kind of servo feedback or sensors as I feel this is unnecessary with these motors. Tuning the frequency should be enough as with all synchronous motors, just wanted to put out there that the earliest electronic motor controller, and the only official one from any major manufac. using these motors in the 50's/60's changes voltage and frequency.

I have seen written the papst aussenlaufers speed is 97% mains frequency, 2-3% torque load and <1% drive voltage

I hope we can develop a modern 3-phase motor controller for these old tables, utilizing a crystal and modern amp, possibly toroids are wideband enough to go down to ~30hz, not sure a 60hz transformer would have response that low.

Phil, definitely will help and stay in correspondence, I feel there is not enough information on this subject for the DIY phonophile.

Have you seen mark kelly's article on the subject?
http://www.clarisonus.com/blog/?p=92
http://www.clarisonus.com/blog/?p=96

He uses 3 audio amps, plus a 9v+9v - 120v transformer to get up to the needed voltage. Should be easy to implement, just need 3 perfectly 1/3-phase shifted sine wave, 3 amps, and 3 decent transformers of the right step-up ratio

I am thinking a DDS (direct digital synthesis) might be ideal as this would allow very fine tuning of frequency, but maybe a synchronous approach with individual clocks for each speed, with fine tuning through changing voltage to the crystal, (would warrant use of a VCXO)

I am also planning a 3-phase supply specifically for Hard drive motors (either delta or Y wired), but this is for either a DIY turntable or upgrading DC drive turntables, as I would prefer to leave these classic tables untouched.
-Alex
Coffee Phil
long player
long player
 
Posts: 2244
Images: 174
Joined: 20 Sep 2008 08:22
Location: California

United States of America

Return to Other Stuff