Hello!
I have many 12V.DC Premotec 9904 120 16141 motors.
Here the spec of the similar motor:
Allied Motion Technologies, Inc - Coreless DC Motors - 9904 120 16703
I have several thorens turntables that have no motors and need something to spin the platters.
I now that with the motor controllers could be used with the well known Premotec 9904-120-18105 12VDC motor.
The problem that my motor is bigger one CL40 instead of CL29 and have a little different specs:
http://premotec.home.xs4all.nl/pdf/coreless/CL29-3 Watt.pdf
http://premotec.home.xs4all.nl/pdf/coreless/CL40-7 Watt.pdf
and it's 7W instead of 3W (like in the 9904-120-18105).
It's also 16141 model (not exactly like 16703 model).
Look please at hte photos. I opened one of such a motor.
Here the photos:
I planed to use this motor with the Origin Live controller or somthing similar.
Help me please to find the answers on several questions:
1. My motor has a different construction than the 9904-120-18105. It has an additional rear thrust bearing for low speed operation. I don't know what for is it? Is it good for the turntables or not?
2. It's bigger and is 7W instead of 3W. Is it possible to use it with the OL speed contollers? Does it produce more noise because of greater power?
3. Look please on on the photos. Is this construction is the same as 9904-120-18105? I see 8 plades that are moving on the metal disc. But this disc has a separete sectors. I think this construction produces a knoking sound? All such kind of the motors have the same construction?
I have many 12V.DC Premotec 9904 120 16141 motors.
Here the spec of the similar motor:
Allied Motion Technologies, Inc - Coreless DC Motors - 9904 120 16703
I have several thorens turntables that have no motors and need something to spin the platters.
I now that with the motor controllers could be used with the well known Premotec 9904-120-18105 12VDC motor.
The problem that my motor is bigger one CL40 instead of CL29 and have a little different specs:
http://premotec.home.xs4all.nl/pdf/coreless/CL29-3 Watt.pdf
http://premotec.home.xs4all.nl/pdf/coreless/CL40-7 Watt.pdf
and it's 7W instead of 3W (like in the 9904-120-18105).
It's also 16141 model (not exactly like 16703 model).
Look please at hte photos. I opened one of such a motor.
Here the photos:
I planed to use this motor with the Origin Live controller or somthing similar.
Help me please to find the answers on several questions:
1. My motor has a different construction than the 9904-120-18105. It has an additional rear thrust bearing for low speed operation. I don't know what for is it? Is it good for the turntables or not?
2. It's bigger and is 7W instead of 3W. Is it possible to use it with the OL speed contollers? Does it produce more noise because of greater power?
3. Look please on on the photos. Is this construction is the same as 9904-120-18105? I see 8 plades that are moving on the metal disc. But this disc has a separete sectors. I think this construction produces a knoking sound? All such kind of the motors have the same construction?
You'll just have to try it to find out. The motor controller should be modified if necessary to handle the higher currents required by the bigger motor. Might be as simple as more heat sink or might require a pass transistor with a greater dissipation rating.
I'd start with something close to what is required with the smaller motor pulley wise and then see if you can use somewhat larger pulleys and run at a lower speed. (Cogging might be more of an issue at lower speeds?)
I'd start with something close to what is required with the smaller motor pulley wise and then see if you can use somewhat larger pulleys and run at a lower speed. (Cogging might be more of an issue at lower speeds?)
Hi,
DC motor speed is directly related to applied voltage theoretically.
However the winding resistance get in the way of good variable speed.
Consequently what you need is a variable voltage source with a
negative resistance equal to the winding resistance. With that
speed will be constant for an applied voltage, the current drawn
will depend on the load, which will be low once up to speed.
rgds, sreten.
DC motor speed is directly related to applied voltage theoretically.
However the winding resistance get in the way of good variable speed.
Consequently what you need is a variable voltage source with a
negative resistance equal to the winding resistance. With that
speed will be constant for an applied voltage, the current drawn
will depend on the load, which will be low once up to speed.
rgds, sreten.
I use an original live motor controller and am very happy with it. They seem to work at their optimum when the output voltage is about 5v. Do you know the rpm per volt rating of your motor? This information seems to be missing from the downloads. If you know this and the diameter of your sub-platter you can calculate the ideal motor pulley size. Ideally the motor speed also wants to be less than 600rpm so that any imbalance in the motor (they all have them to some extent) is going to produce vibration well below the audio bandwidth. If the motor fits both of these criteria then the ol controller is definitely worth considering. Origin live do offer a 30day return policy so you can try it and return it if it doesn't work.
Niffy
Niffy
Niffy, do you use the Origin Live controller with the original motor of your deck or do you use the OL motor? Does the motor run quietly?
The reason I asked: I purchased the OL controller + motor earlier this year. The motor was intolerable noisy and speed was not stable from one day to the next. Appart from that there was a considerable improvement of the sound. Finally I sent it all back and now I'm trying to build my own motor controller.
Boris
Hi Boris.
I am using the advanced controller and the dc200 motor. Speed stability is rock solid and I get no drift. I periodically check speed accuracy and it never changes. Apparently the standard model is less stable and is prone to drift. Which controller and motor did you audition? The motor is not as quiet as I had hoped it to be, I can just hear it from about a foot.
The dc200 has a speed constant of about 265rpm/volt and as I am running it at about 500rpm means that I am feeding it less than 2volts. I am hoping to upgrade the motor to a maxon re29 with a speed constant of about 100rpm/volt. The re29 seems to be the perfect motor for dc turntable drive but is not cheap. I'm waiting to see if one come up cheap as excess stock on eBay. A lot of other models do so fingers crossed.
Terrom
I've found the speed constant for your permotec motor (it was presented inverted). It is about 320rpm/volt which is a bit high and would require a low driving voltage. I have no complaints using my unit at low voltage. Your motor is a relatively low voltage model (most dc turntables seem to use 24 or 48volt) so will hopefully run nicely at a low voltage input. Alternatively you can run the motor a bit faster. Origin live run their motors at about 1200rpm which is faster than I would personally choose. Having said that origin live decks are some of the best sounding commercial decks available and 1200 rpm equates to a primary motor resonance of only 20hz. Of course the actual motor speed and controller voltage will be dependent on the ratio of the sizes of the sub-platter to motor pulley. We're you planning on making your own pulley or purchasing a commercial model? Origin make one with a 7.5mm crown but it is expensive at about £30.
The maxon motor I'm looking at is 15watts, I've seen 20watt motors used so I wouldn't worry about 7watts being too high.
The knocking sound is, as stated by Arch, caused by the brushes. Once the motor has run in fully this noise should have dramatically reduced. This can take a long time.
Niffy
I am using the advanced controller and the dc200 motor. Speed stability is rock solid and I get no drift. I periodically check speed accuracy and it never changes. Apparently the standard model is less stable and is prone to drift. Which controller and motor did you audition? The motor is not as quiet as I had hoped it to be, I can just hear it from about a foot.
The dc200 has a speed constant of about 265rpm/volt and as I am running it at about 500rpm means that I am feeding it less than 2volts. I am hoping to upgrade the motor to a maxon re29 with a speed constant of about 100rpm/volt. The re29 seems to be the perfect motor for dc turntable drive but is not cheap. I'm waiting to see if one come up cheap as excess stock on eBay. A lot of other models do so fingers crossed.
Terrom
I've found the speed constant for your permotec motor (it was presented inverted). It is about 320rpm/volt which is a bit high and would require a low driving voltage. I have no complaints using my unit at low voltage. Your motor is a relatively low voltage model (most dc turntables seem to use 24 or 48volt) so will hopefully run nicely at a low voltage input. Alternatively you can run the motor a bit faster. Origin live run their motors at about 1200rpm which is faster than I would personally choose. Having said that origin live decks are some of the best sounding commercial decks available and 1200 rpm equates to a primary motor resonance of only 20hz. Of course the actual motor speed and controller voltage will be dependent on the ratio of the sizes of the sub-platter to motor pulley. We're you planning on making your own pulley or purchasing a commercial model? Origin make one with a 7.5mm crown but it is expensive at about £30.
The maxon motor I'm looking at is 15watts, I've seen 20watt motors used so I wouldn't worry about 7watts being too high.
The knocking sound is, as stated by Arch, caused by the brushes. Once the motor has run in fully this noise should have dramatically reduced. This can take a long time.
Niffy
So I coldn't buy anything out of the box like the Origin Live because they only work perfecrly with the matched motors (where negative output impedance = the
motor winding resistance)? The only way is to produce the own controller where negative output impedance = the motor winding resistance?
motor winding resistance)? The only way is to produce the own controller where negative output impedance = the motor winding resistance?
I normally read it from spec sheets. For the origin live I know the speed and measured the voltage.
Niffy
Hi sreten.
From what you're saying my plan to upgrade/test my origin live controller with a maxon re29 with a lower speed constant may not work as planned. I would appear that I need to find a motor with exactly the same dc resistance as the origin live motor or I will loose speed stability. Is this correct?
As the motor is dc I assume that all I need to do is stick a test meter across the non-rotating motor to determine its resistance.
Also if a motor I find is not an exact resistance match could I add a resistor in parallel or series to increase or decrease its resistance to obtain the perfect resistance required by the controller? The motor/resistor combination would of course have a different speed constant to just the motor. Or is it a more complex relationship than this?
Thanks
Niffy