diy Turntable - AC Motor Control

[Rick H]

I'm new to the forum here but have been researching a bit before building my own diy turntable...

I see it is a common problem on motor speed control.

Why wouldn't this low cost solution work?
Variable Frequency AC Drive - AC MOTOR SPEED... Perhaps we can use this to set up multiple precision speeds. Or am I newbie making a mistake *_*

Here are a few links for research:

9503 MULTI SPEED BOARD
www.kbelectronics.com/manuals/kbvf_2g.pdf

KBVF Multi-Speed Board | Part No. 9503 - KB Controls

upload.sunfenglin.com/GongKong/download/KBAC.pdf

 

[Rick H]

I was thinking most any low-cost synchronous motor/s may work? I see them available in the $20-30 range on eBay.

The controller is very low cost too... it looks like they can be had new for about $30 and will work on 110 & 220v.
Here I found a new one for about $13.00 and delivery is free.
9503 MULTI SPEED BOARD KB - NIB - 1 YEAR WARRANTY | eBay

The output is a bit high but perhaps a few resisters on the output may correct that.
I was hoping a few of the experts could chime in on this.

Regards,
Rick

 

[Rick H]

I see now... we need this too and that will raise the cost. It still may be a good alternative as they are readily available.

I'm not certain what motors would work... the trim pots should make them very accurate once setup.
Perhaps they sell a smaller unit too... it says fractional hp but the range is quite large/high on this one.
KB ELECTRONICS KBVF-23D KBVF23D AC DRIVE | eBay
http://www.walkerindustrial.com/pdf/kbvf.pdf

I'll have to research this a bit more.

 

[Rick H]

Would this work with these small motors?

THALES AVIONICS ELECTRICAL 26 OHM 3-PHASE MOTOR USED | eBay

THALES AVIONICS ELECTRICAL 33OHM 3-PHASE MOTOR USED | eBay

 

[Rick H]

I apologize if I seem to be bombing the board here but I think it would not only help me but many others here.

After researching a bit more... this is a much better solution:

The controllers (a few different choices) and the motors are readily available for very low cost and the speed precision is highly regulated (it appears the motors even provide feedback).

ORIENTAL SPEED CONTROL | eBay

Has anyone else here built around this?

 

[1audio]

Most of those controllers are designed for 3 phase motors. They also generate a lot of EMI and RFI, not to mention the acoustic squeal many make.

You are better off finding a hysteresis synchronous motor and building a two phase drive. There are a number of articles floating around the web for doing this. I would caution against digital solutions, they can also be serious emi generators. A state variable oscillator and a stereo IC power amp (LM3886 X2 or equivalent) can do a very good job of driving a motor with very little torque ripple.

 

[ByronInPortland]

I've never heard of Oriental Speed Control. I would be wary of buying a very cheap motor and controller. I'm pretty sure the old Linn and Ariston turntables used motors from McLennan, and they currently make a hysteresis motor specifically for turntables here: Motors
I've no idea what the price is. Have you seen this thread? http://www.diyaudio.com/forums/anal...cial-turntable-drive-system-motor-thread.html

Good luck.

 

[1audio]

The Oriental products are decent industrial motors and controllers. They are used a lot in manufacturing machinery. I don't think they are right for a turntable.