Turntable Motor

booangler · 2896

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Offline booangler

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on: August 11, 2013, 09:23:34 AM
Hello All,

Can someone tell me the purpose of the capacitor in this diagram? https://docs.google.com/file/d/0B5DyIacd8HbieUFXQnlZeWJ1MEE/edit?usp=sharing

Also, how much filtering of the 24v AC power supply am I going to need to maintain a steady speed suitable for use in a TT?
« Last Edit: August 11, 2013, 09:26:51 AM by booangler »

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Offline Paul Birkeland

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Reply #1 on: August 11, 2013, 11:00:26 AM
Hello All,

Can someone tell me the purpose of the capacitor in this diagram? https://docs.google.com/file/d/0B5DyIacd8HbieUFXQnlZeWJ1MEE/edit?usp=sharing

Also, how much filtering of the 24v AC power supply am I going to need to maintain a steady speed suitable for use in a TT?

That is a motor run capacitor.

I don't understand the AC filtering question, what are you attempting to accomplish?

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline booangler

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Reply #2 on: August 12, 2013, 03:01:42 AM
Mr Blackplate,

A friend is try to build himself a TT but he has little experience with circuitry so he asked me to look at the diagrams. The packaging came with way more diagrams than I included. I was able to get him started in the right direction at least. He then asked me about the purpose of the capacitor to which I didn't have an answer but do know. He also asked me how complex power he would need. Seems that in his research he has seen articles and post that indicate some builders go a to great lengths designing the supplies. I hindsight my choice of words may have been incorrect. To restate the question:

Would a simple 120 to 24 volt transformer work for a turntable supply or do I need to tell him to look for something better designed than that?

Also, does the type and quality of the cap used for the motor start have any impact on the motor performance?

Thanks,

Alan
« Last Edit: August 12, 2013, 03:29:41 AM by booangler »

The joy of music should never be interrupted by a commercial - Leonard Bernstein

Denon POA | PJCCS Quickie | Hagerman Bugle | SOTA Sapphire w/ Grado Gold | B&W 602


Offline Paul Birkeland

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Reply #3 on: August 12, 2013, 03:56:59 AM
I wouldn't go nuts on the quality of the cap.  Likely, there will be different values specified for this capacitor depending on whether or not your AC is 50 or 60Hz.

Something like thiswill be sufficient to get you started unles the motor requires more power.

If the wall power available has a frequency that fluctuates, then you can go through all the effort to build a regenerator.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline booangler

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Reply #4 on: August 12, 2013, 06:36:22 AM
Thank you Paul.

One more question for you?

Will this work for the cap? 5.6 was the specified size for the Cap. I stepped up the voltage simply to create a safety margin.

Cheers,

Alan
« Last Edit: August 12, 2013, 08:24:42 AM by booangler »

The joy of music should never be interrupted by a commercial - Leonard Bernstein

Denon POA | PJCCS Quickie | Hagerman Bugle | SOTA Sapphire w/ Grado Gold | B&W 602


Offline Paul Birkeland

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Reply #5 on: August 13, 2013, 08:07:47 AM
It's funny, I've never seen a Tantalum capacitor used as a motor run cap.  A quick search yields no solid answer for this, but I suspect that they may have some performance limitations just based on how small they are. 

Usually you see something like this.


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline booangler

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Reply #6 on: August 14, 2013, 03:52:55 PM
PB,

We are going to do some experiments once more of the parts get in. I will report back our results.

My Best,

Alan

The joy of music should never be interrupted by a commercial - Leonard Bernstein

Denon POA | PJCCS Quickie | Hagerman Bugle | SOTA Sapphire w/ Grado Gold | B&W 602