re: E50 assembly
Some observations I've made over the years.
1) the self-aligning bushings need to swivel freely within their mounts so that it is possible to align these bushings to the shafts. Other words -- If the bushings are too tightly held by their clips so that they do not swivel easily, that could prevent you from getting an adequate alignment betwixt shaft and bushings.
2) The nickel core plates need to stack up uniformly and present a solid square block. This also is essential to an adequate motor build. However I have seen some older motors with core stacks that were severely warped. These can prevent good shaft/bushing alignments because when you tighten the case ends down, the warped surfaces of the cores pull against the end casings unevenly - causing a new misalignment between shaft and bushings.
The cores I speak of can be seen in the above photo right foreground.
As far as I know, no one is producing replacement E50 cores at this time. But there may come a day when it becomes necessary as E50 supplies run thin.
To identify this condition place the outer casings loosely over the core stacks and observe for gaps between mating surfaces. And if you can't find any such gaps about which I speak, good. But do make certain that the assembled bushings do swivel freely within their fit-up. Without this, it will be difficult.
-Steve
Some observations I've made over the years.
1) the self-aligning bushings need to swivel freely within their mounts so that it is possible to align these bushings to the shafts. Other words -- If the bushings are too tightly held by their clips so that they do not swivel easily, that could prevent you from getting an adequate alignment betwixt shaft and bushings.
2) The nickel core plates need to stack up uniformly and present a solid square block. This also is essential to an adequate motor build. However I have seen some older motors with core stacks that were severely warped. These can prevent good shaft/bushing alignments because when you tighten the case ends down, the warped surfaces of the cores pull against the end casings unevenly - causing a new misalignment between shaft and bushings.
The cores I speak of can be seen in the above photo right foreground.
As far as I know, no one is producing replacement E50 cores at this time. But there may come a day when it becomes necessary as E50 supplies run thin.
To identify this condition place the outer casings loosely over the core stacks and observe for gaps between mating surfaces. And if you can't find any such gaps about which I speak, good. But do make certain that the assembled bushings do swivel freely within their fit-up. Without this, it will be difficult.
-Steve
Yes I believe that but that motors were new most E50 rotorshafts have a wear pattern so friction is a issue and polishing recommended.
Regarding the 2 mm movement. Any movement is fine as long as it's some movement. If the motor is run on it's side usually when powered it moves to a centre position. So if to the top of the movement it moves down and the bottom it moves up. I don't know if this will be seen if the bearings are tight. I suspect not. Shafts can be polished with metal polish. On the whole better some metal is lost than rough. If it looks good leave it alone. The sticks ladies use to polish nails work well. In UK Boot No7.
Indeed some movement is ok but people always ask how much and the E50 motor uses a build in limit for vertical play .
Indeed Kevin with Papst there is a limited supply I'm testing some motors some time know but they all are old stock had tested a new one from Bodine some time ago but produced to much vibration . Even tried a dc motor but this had problems with speed stability .There are some interesting motors from Germany AEG they were used in taperecorders and producing little vibration must test them further.
The problem is motors in many cases do not equal the E50. You only need to put your fingers on a working example to feel how low the vibration is. What you might not see is how ideal the motor is and has perfect compromises. My friend who is PHD in such things says the torque relationship of the rotor to the field is elastic. This is not how other designs work. Most other motors fight to lock. This is for us a weakness. As I was corrected to say E50 is squirrel-cage. Ironically as I wrote pages about it in 1972 except our text books didn't show the laminations. If you look carefully these assist the smooth rotation as they are staggered. Some mistake this for a hyper cheap way of doing it as it lives on in very cheap 2 pole room heaters ( £10 ). Surprisingly these are almost good enough. Like vacuum cleaners very sophisticated manufacture is possible for low price whilst a market exists.
The Linn LP12 motor is not unlike a central heating type at £5, The LP12 type is now £70 as a replacement type. It is not as good as the E50.
An electronically governed clockwork motor would be interesting.
The Linn LP12 motor is not unlike a central heating type at £5, The LP12 type is now £70 as a replacement type. It is not as good as the E50.
An electronically governed clockwork motor would be interesting.
Sorry if this has been covered before. For those of you using the Schopper idler wheel noise reduction kit, are you finding that you have to replenish the cup periodically? I started hearing a little rumble and sure as heck the cup was dry. I performed some cleaning and lubing while I was in there so I can't say with certainty that the source of the noise was the dry cup, (I think it was) but the table is much quieter now.
BLWS231S-24-2000 BLDC
I've been wondering if Pyramid's BLWS / MA-3D / SG4 project could be adapted (via a mounting plate etc) for a TD-124. Your thoughts on the viability of this?
KH
Hi Kevin,
I've been wondering if Pyramid's BLWS / MA-3D / SG4 project could be adapted (via a mounting plate etc) for a TD-124. Your thoughts on the viability of this?
KH
I have a confession.. LOL I bought a Papst 3 phase Aussenlaufer motor for one of my TD-124s about 4 years ago, and earlier this year finally got it running on my older TD-124 (original series) using a Siemens Micromaster 410 with a sine wave reconstruction filter designed by a friend. To say it is an improvement over the POS E50 is something of an understatement.
Anyone who comes up with an AC 3 phase drive and motor for these tables should have a ready market amongst those looking to take it to the next level.
Smooth as glass....
Anyone who comes up with an AC 3 phase drive and motor for these tables should have a ready market amongst those looking to take it to the next level.
Smooth as glass....
I was wondering how it was going with the Papst. And with the Papst the eddy brake remains functional.
Now we wait for someone to offer a kit that includes the 3phase motor with controller for under 1K..
-Steve
Pyramid system
Well, with the SG4 and 3 class-D amps and some step-up transformers that is what I want to with the two TD-124s I have, since they both have Papst motors.
Any idea how accurately the Papst motor can be kept at a set RPM without an eddy brake? I have a 3rd Papst motor and 40cm platter from a Micro-Seiki DD-100 (gutted by some blighter) that I'm considering building into a TT of some sort with a 12" tonearm (either an Opera or Jelco on a separate brass pod.)
Well, with the SG4 and 3 class-D amps and some step-up transformers that is what I want to with the two TD-124s I have, since they both have Papst motors.
Any idea how accurately the Papst motor can be kept at a set RPM without an eddy brake? I have a 3rd Papst motor and 40cm platter from a Micro-Seiki DD-100 (gutted by some blighter) that I'm considering building into a TT of some sort with a 12" tonearm (either an Opera or Jelco on a separate brass pod.)
I believe there are two types of the Papst 3 phase motor, synchronous and asynchronous. The type made by Papst for the TD124 is of the latter type, whereas most of the ones available on the secondhand market are synchronous.
The difference arises with the material of the external rotor; the synchronous versions use a high hysteresis steel(often laminated to reduce eddy current losses), asynchronous versions use a softer iron rotor which allows the motor to operate as an induction motor with some slip. Another, larger version of this type is, I believe, also used in the Revox B99 tape recorder capstan motor, which has a tachometer ring used as part of the speed control circuitry.
If I am right, and it is a big if (please can anyone provide either confirmation or rebuttal), then the Papst motor used originally on the TD124 is probably not the best type to use with an external VFD like Pyramid's SG4. It is however the best type if you want to continue to make use of the eddy current speed control.
The difference arises with the material of the external rotor; the synchronous versions use a high hysteresis steel(often laminated to reduce eddy current losses), asynchronous versions use a softer iron rotor which allows the motor to operate as an induction motor with some slip. Another, larger version of this type is, I believe, also used in the Revox B99 tape recorder capstan motor, which has a tachometer ring used as part of the speed control circuitry.
If I am right, and it is a big if (please can anyone provide either confirmation or rebuttal), then the Papst motor used originally on the TD124 is probably not the best type to use with an external VFD like Pyramid's SG4. It is however the best type if you want to continue to make use of the eddy current speed control.
I have put it off long enough. I bent the armboard back. It worked out great and now I am onto final run in of my rebuilt motor. I sent my main spindle down to Woodsong audio for refurb a while back. I will post my results once I get to test it out. It has new bearings, ball and thrust plate. It looks great! I will post pictures soon. My computer is old and I can not access Diyaudio on it anymore. I found a tablet but it takes a long time to type with it. Also do not know how to post a pic yet with it.
M
M