DC motor speed control

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I've been trying to find the right motor speed controller for my diy tt. The DC motors I can find, but a manufactured speed controller that meets my needs is hard to find.

I have very little expieriance in electronics, although I think I could sodder a kit together, so I was looking for one off the shelf. I can find many small, inexpensive PWM type controllers but those types of controllers are not recommended for TT use. I may have to resort to calling for some help from friends to build one from scratch.

Has anyone built one similar to the one used by Teres? I like the idea of getting the feed back info right from the platter speed itself, but I do not need the soft start and stop function, etc. If anyone has the plans or diagrams for such a controller I would like to get a copy.

If anyone knows of an off the self controller that is very small, will work with the Maxon 110187 motor with encoder, and is reasonably priced please let me know.

Thanks for any help you can give.

George
 
Maxon make small controllers for their motors, and they have an encoder interface option. Encoders are too difficult for those with little experience in electronics, and not easy for those with plenty of experience.
A variable voltage dc power supply will control the speed, but once you talk of adding feedback from the TT, it gets very complicated.
It's a project I have in mind, but is low down on the "to do" list.:)
 
Update

I came across a DC brushless motor and controller combo from Oriental Motor Co. It was small enough to fit into my motor box, and it looked like a quality motor. At $217.00 it should be a quality motor.

The motor controller was way "over kill". Much more complex, with more features and capabilities that I needed. It also needed a stable, regulated 24 volt power supply. I finally got it put together and installed on my TT. It does a great job of constant, accuate speed control, but the motor is very noisy. I can hear it from across the room.

Well, back to the drawing board. I am not going to give up though. I am still searching for the right speed controller. I plan on using a Maxon motor for my next attempt.

George
 
I've just finished (well, it's never finished!) a turntable. I nicked a capstan motor from an old VHS to use as it's more substantial than the usual types.

I had a problem keeping wow down, and the motor was noisy, so a PSU had to be built. I cobbled a simple one together yesterday using a thrown out low voltage lighting transformer and LM317T regulator and it's sweet now. Easy to construct inside the TT, variable speeds, switchable on/off and 33/45 and strobe too. I insulated the motor to cut down the noise and it's much quieter.

This simple PSU has no feedback from the platter, but it only cost $15 australian, so it might be enough to get your TT going! I can supply details if your interested.
 
jaudio

My platters weighs about 16 lbs. It is 1.5" thick acrylic with 9 pockets filled with lead shot. I've been using fishing line for the drive belt and I have to give the platter a turn with my hand when it's first turned on. Once it's up to speed the DC motor maintains that speed very well. I got one of those Dual strobe disks and LED pen lights from that guy on EBay to check my speed.

The noisy motor may get quieter as it breaks in. And I haven't contacted Oriental motor co. yet to see if that much noise is normal.

George
 
Easy to make a controller

DC Motor Controlers are easy to make.....you'll need a few op amps, a mosfet, some caps and resistors, a 555 timer.....optional thing is a sensor to detect motor speed...you can monitor the Back EMF if you don't want to use a sensor. i might have a schematic i will look and let you know. Dart Controls makes stuff. You can buy directly from them and they have distributors. Google'em.
 
sorry

no luck on digging up the schematic. it was a design project from a class about 2 years ago. I have apparently deleted alot of stuff since then. If i come across anything i will be certain to post it. Sorry again. I'll look through some of the controls we make at work and see if one comes up that is simple and will work for your application (I am just a rookie repair tech, other wise i would just design something real quick). What kind of motor are you using? That would help me narrow it down quicker. After all the times i have been asking questions on these boards i am anxious to finally give an answer.
 
Not sure if this would be of use to you if modified a little but here is one of dc motor speed controlls I found when looking for one myself last year .I have other ones on another computer but don't have access to it right now.
I have not built this one nor do I remember where I got it even but I hope it is of use to you.
 

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Thanks Fortuocity,

See... that's exactly what I was looking for. Complex enough to give very accurate speed control, but simple and small enough to be built on strip board and fit in the TT chassis.

The only mod I will make is to measure the resistances over the speed control pot (as the circuit is) and insert a switch, resistors and 10k pots to give two speeds, and finer speed control.

Thanks a lot for that!:up:

Just as I put the soldering iron away....
 
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