Hi Mark. If you're still around I got a question for you reguarding the pulley needed to work with your controller. Here a comment from you from the previous group buy and my own testing. Please can you comment? We really need to insure that we get a compatible pulley or maybe you can specify a motor that will work better with the existing Teres pulley. Thanks in advance...
Pulley problem.
Here is what Mark Kelly said:
"For the 110191 motor with the 12V controller the pulley to platter step up ratio MUST NOT be greater than 24 : 1 if you wish to include 45rpm" If using platter drive that is. Platters usually being 300mm?
That means that with the 12volt supply a pulley should be 13mm wide.
Thanks Bas for bringing up this problem. It seems we got stuck, at least for the 45 rpm. I got to work something here.
From my own calculations using the Teres Pulley dimensions I got:
Teres pulley diam=10.98mm,
Teres platter diam=310.515mm,
pulley ratio = 10.98/310.515 = 0.0353865 or 28.26 > 24 as recommended by Mark kelly...
Motor specs = 126rpm/V
33-1/3rpm = motor 941 rpm= 7.5V
45rpm = motor 1271rpm= 10.0V.
From my own prototype the Controller range = 6.2 to 11.2V with current feedback activated.
So maybe it can work after all. I have to try it with actual motor.
If I use Mark recommended ratio of 23.07 (300mm platter / 13mm pulley) I got:
33-1/3rpm = motor 768 rpm= 6.05V
45rpm = motor 1038 rpm = 8.17V
I'm confused here. From these values, I would expect the controller to work only for 45rpm but not 33rpm. The controller behavior is probably different with the actual Maxon motor than with my actual test motor. I'll need the real motor to see.
Pulley problem.
Here is what Mark Kelly said:
"For the 110191 motor with the 12V controller the pulley to platter step up ratio MUST NOT be greater than 24 : 1 if you wish to include 45rpm" If using platter drive that is. Platters usually being 300mm?
That means that with the 12volt supply a pulley should be 13mm wide.
Thanks Bas for bringing up this problem. It seems we got stuck, at least for the 45 rpm. I got to work something here.
From my own calculations using the Teres Pulley dimensions I got:
Teres pulley diam=10.98mm,
Teres platter diam=310.515mm,
pulley ratio = 10.98/310.515 = 0.0353865 or 28.26 > 24 as recommended by Mark kelly...
Motor specs = 126rpm/V
33-1/3rpm = motor 941 rpm= 7.5V
45rpm = motor 1271rpm= 10.0V.
From my own prototype the Controller range = 6.2 to 11.2V with current feedback activated.
So maybe it can work after all. I have to try it with actual motor.
If I use Mark recommended ratio of 23.07 (300mm platter / 13mm pulley) I got:
33-1/3rpm = motor 768 rpm= 6.05V
45rpm = motor 1038 rpm = 8.17V
I'm confused here. From these values, I would expect the controller to work only for 45rpm but not 33rpm. The controller behavior is probably different with the actual Maxon motor than with my actual test motor. I'll need the real motor to see.
The circuit uses a series / shunt regulator to control the output voltage, it needs to drop at least 2 Vbe across the series CCS. It also needs to drop roughly 2 Vbe across the current mirror for the compensation circuit. Taking 11.4V nominal supply - 4 x Vbe the max output voltage is around 9V.
The no-load voltage for the motor needs to be far enough below that for the motor to be able to develop enough torque to drive the platter. Accordingly, I prefer a no-load voltage of 7.5 volts or less, the 110191 runs at 900rpm (x 20 for 45). The absolute limit is 9V which is 1080RPM hence x 24. The motor will develop very little torque at this speed, so you would need to keep the battery very well charged.
There are several options to get around this:
1. Use a different pulley.
2. use 18V or 24V supply (watch the heatsinks on the transistors if you do this)
3. use an 110189 motor (the original Teres motor) for which 7.5 V = 1350 rpm
4. Use a 226774 motor for which 7.5V = 1538 rpm
5. build a different supply.
I chose option 1, I'm now working on option 5.
The no-load voltage for the motor needs to be far enough below that for the motor to be able to develop enough torque to drive the platter. Accordingly, I prefer a no-load voltage of 7.5 volts or less, the 110191 runs at 900rpm (x 20 for 45). The absolute limit is 9V which is 1080RPM hence x 24. The motor will develop very little torque at this speed, so you would need to keep the battery very well charged.
There are several options to get around this:
1. Use a different pulley.
2. use 18V or 24V supply (watch the heatsinks on the transistors if you do this)
3. use an 110189 motor (the original Teres motor) for which 7.5 V = 1350 rpm
4. Use a 226774 motor for which 7.5V = 1538 rpm
5. build a different supply.
I chose option 1, I'm now working on option 5.
Could anyone run through the math to set the DIP switches? I need 5.10v for 33rpm and 6.70v for 45rpm. I see how the voltage divider works, so 10v/6.7v*50k = 74.6k and then 10v/5.1v*50k = 98.0k. I'm using the single turn 5k trimpots from the group buy. VR1 is around 10k, I haven't really messed with it much. Sorry, this is a pretty basic question I know.
Also, 5.1v seems low, perhaps the 1k needs to be changed that bypasses the motor terminals?
here's the relevant info from the docs:
"To set the range, select resistors to give the centre point of the potentiometer at the required voltage, the full scale output of the
controller being 10.0 volts. For say 7.5 volts we would need the pot centred at 12.5k / 37.5k so we would select 10k plus half the
pot above the set point and 20k,10k, 4k75 plus half the pot below. The DIP switches would thus be set to 1,0,1,1,1,0,0,0."
Also, 5.1v seems low, perhaps the 1k needs to be changed that bypasses the motor terminals?
here's the relevant info from the docs:
"To set the range, select resistors to give the centre point of the potentiometer at the required voltage, the full scale output of the
controller being 10.0 volts. For say 7.5 volts we would need the pot centred at 12.5k / 37.5k so we would select 10k plus half the
pot above the set point and 20k,10k, 4k75 plus half the pot below. The DIP switches would thus be set to 1,0,1,1,1,0,0,0."
I figured it out!
I worked backwards from the example:
7.5v/10v*50k = 12.5k/37.5k
1 0 1 1 = 10k + 5k / 2 = 12.5k
1 0 0 0 = 20k + 10k + 4.75k + 5k / 2 = 37.25k
Then for my setup:
6.7v/10v*50k = 16.5k/33.5k
1 0 0 1 = 10k + 4.75k + 5k / 2 = 17.25k
1 1 0 0 = 20k + 10k + 5k / 2 = 32.50k
5.1v/10v*50k = 24.5k/25.5k
0 1 1 0 = 20k + 2.5k + 5k / 2 = 25k
0 1 1 0 = 20k + 2.5k + 5k / 2 = 25k
I worked backwards from the example:
7.5v/10v*50k = 12.5k/37.5k
1 0 1 1 = 10k + 5k / 2 = 12.5k
1 0 0 0 = 20k + 10k + 4.75k + 5k / 2 = 37.25k
Then for my setup:
6.7v/10v*50k = 16.5k/33.5k
1 0 0 1 = 10k + 4.75k + 5k / 2 = 17.25k
1 1 0 0 = 20k + 10k + 5k / 2 = 32.50k
5.1v/10v*50k = 24.5k/25.5k
0 1 1 0 = 20k + 2.5k + 5k / 2 = 25k
0 1 1 0 = 20k + 2.5k + 5k / 2 = 25k
ok, more results. With the motor off, I measured 70.4R at the terminals, including the 1k resistor. I then disconnected one lead of the motor and switched the unit to the 45 rpm setting. At this point the current compensation was disabled via the jumper. I then measured 6.49v at the motor terminals. I connected 70.4R in series with one of the motor leads and dialed VR1 to 6.49v exactly, while the motor was running my turntable. I then put the jumper in the position to enable current compensation.
Now, when I try and set the speed it seems to oscillate a bit. The pattern moves to the right for an inch and then back to center and to the left for an inch and repeats this pattern. The adjustment controls are very sensitive.
Per the calculations below, my DIP switches are:
11000110 for 45rpm (6.7v)
10011001 for 33rpm (5.1v)
where, 1 is when the actuator is moved towards the adjustment pots, and 0 is when the actuator is moved towards the "on" label of the switch (i.e. to the back of the case). The numbers are read left to right.
Did I miss something obvious?
Now, when I try and set the speed it seems to oscillate a bit. The pattern moves to the right for an inch and then back to center and to the left for an inch and repeats this pattern. The adjustment controls are very sensitive.
Per the calculations below, my DIP switches are:
11000110 for 45rpm (6.7v)
10011001 for 33rpm (5.1v)
where, 1 is when the actuator is moved towards the adjustment pots, and 0 is when the actuator is moved towards the "on" label of the switch (i.e. to the back of the case). The numbers are read left to right.
Did I miss something obvious?
hm... one quick question. When you measure the voltage with the motor disconnected, is the jumper supposed to be connected to ground (no current) or to motor return? I get 2 different voltages, depending which on where the jumper is placed, so I'm not sure voltage I'm supposed to try and get when turning VR1........guess I'm finally out of ideas 
Mark Kelly said:
after I adjust the motor according to the documentation, the strobe pattern moves forward an inch and then backwards 2 inches and repeats this pattern... At this point the controls are very touchy. If I move the jumper to disable this feature, the controls work very well (easy to adjust) and I can get the strobe pattern to stop on a dime.
Also, one thing that is not clear from the documentation. When you measure the voltage with the motor disconnected, is the jumper supposed to be connected to ground (no current) or to motor return? I get 2 different voltages, depending which on where the jumper is placed and this might be the cause of the above issue.
I have no problem repeating the procedure and carefully documenting my steps, if that will help.
Thanks!
The motor voltage is measured at the motor terminals.
IIRC the bypass resistance across the terminals must be included to get an accurate result.
The wander might be simply because you have the compensation turned up too high. Try turning it down.
The other possibility is that the op-amp which supplies the current compensation is fried (the OPA2277s are very sensitive to ESD).
IIRC the bypass resistance across the terminals must be included to get an accurate result.
The wander might be simply because you have the compensation turned up too high. Try turning it down.
The other possibility is that the op-amp which supplies the current compensation is fried (the OPA2277s are very sensitive to ESD).
Hi ,just complete the PCB, i have made a mistake by putting OPA2227into IC3 and the voltage ref into IC2 and power on
now following power shooting as per documentation and the motor is on even when IC4 is removed .
Any ideas what i would likely have "fried"?
The voltage ref on pin 6 of voltage ref is measured at 5V at moment.
now following power shooting as per documentation and the motor is on even when IC4 is removed .
Any ideas what i would likely have "fried"?
The voltage ref on pin 6 of voltage ref is measured at 5V at moment.
Mark Kelly Controller PCB for sale
Hi. I had built a few of these PCB. If still interested send me an email at: bergeron_dot_syl_ at_ videotron_dot_qc_dot_ca
Thanks...
Email address edited by moderation to prevent harvest by roving spambots.
Hi. I had built a few of these PCB. If still interested send me an email at: bergeron_dot_syl_ at_ videotron_dot_qc_dot_ca
Thanks...
Email address edited by moderation to prevent harvest by roving spambots.Algar , do you (or anybody) by any chance have a spare string pulley from Maxon motor contoller 2008 GB? Finally Im getting together all the pieces of table from machinist today and it evolved into sort of suspended hybrid. Knowing the problems of getting tape drive to work on stable mass table I have no doubts it will be pita on rigid but still springy suspension. (At this point I wouldn't want to bother machinist into making that pulley
Regards, L
Regards, L
Hi Limolo. Original tape pulley from Teres Audio was just great. It is just that it can be used only at 33rpm, not 45, but this is not an issue for me.
That is the best pulley you can get for the money, and it fits the maxon motor perfectly. Just give them a call, this is your best option. Otherwise search for a 10mm diam pulley. A lot of table manufacturers got one.
That is the best pulley you can get for the money, and it fits the maxon motor perfectly. Just give them a call, this is your best option. Otherwise search for a 10mm diam pulley. A lot of table manufacturers got one.
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