Quote:
‘I guess what I am saying is... John2 you are right that this is the best way to do it, but how are we going to do it? I don't have the time to inspect each one and verify concentricity and bore diameter.’
Trying to maintain .0005” tolerance with a boring bar for batch production is fanciful. However, a boring bar is essential for concentricity, as previously set out, hence, my agreement with using said bar. The important point I failed to address previously (forgive me) is that .0005” is a feasible batch tolerance with a suitable, very carefully centred, reamer.
Locktite OK if the pulley is very close fitting-if not it is no ‘self-centring’ panacea!
‘I guess what I am saying is... John2 you are right that this is the best way to do it, but how are we going to do it? I don't have the time to inspect each one and verify concentricity and bore diameter.’
Trying to maintain .0005” tolerance with a boring bar for batch production is fanciful. However, a boring bar is essential for concentricity, as previously set out, hence, my agreement with using said bar. The important point I failed to address previously (forgive me) is that .0005” is a feasible batch tolerance with a suitable, very carefully centred, reamer.
Locktite OK if the pulley is very close fitting-if not it is no ‘self-centring’ panacea!
superhkm said:
I will send payment requests when I have received the PCBs (hopefully this week), built a controller and tested it to ensure that it performs as promised. Since the changes from the prototype PCBs were very minor I'm 99% confident we'll be OK. Not sure what I do with the other 1% though.
BTW I don't yet have all the components - am waiting for the OPA2277s which were out of stock with all major suppliers but which GaryB was kind enough to source for me in the US. They should be here soon.
Re: Controller at Higher/Lower Voltage
To run on higher voltage requires the following changes, referring to the schematic as posted on my website Here
C1 must be changed to one rated for the new input voltage.
R1 and R2 must be changed to give the higher voltage output from the L200C, the relevant formula is Vout = 2.75 * (R1 + R2) / R1, this must be at least 3 V below the relevant Vin plus it must be below 33 volts unless input protection is provided to IC3. In any case the maximal output from the L200C is 37V. WARNING: IF Vout IS CHANGED THE BATTERY CHARGER OPTION CANNOT BE USED
The output voltage set resistors R17 and R18 must be changed so that Vmax * (R17 + R18) / R18 is 5 volts or less.
JRags said:
To run on higher voltage requires the following changes, referring to the schematic as posted on my website Here
C1 must be changed to one rated for the new input voltage.
R1 and R2 must be changed to give the higher voltage output from the L200C, the relevant formula is Vout = 2.75 * (R1 + R2) / R1, this must be at least 3 V below the relevant Vin plus it must be below 33 volts unless input protection is provided to IC3. In any case the maximal output from the L200C is 37V. WARNING: IF Vout IS CHANGED THE BATTERY CHARGER OPTION CANNOT BE USED
The output voltage set resistors R17 and R18 must be changed so that Vmax * (R17 + R18) / R18 is 5 volts or less.
Regarding to the schematic I've got a few questions:
Some connections are very simple.. X1 is for the power supply, X5 is for the motor, X3 connects to X6 on the adjustment board. But I don't get what X4 is for.
JP2 was to choose between feedback and capacitors, right? But which position is which? And can they be combined, or is it possible to eliminate some parts when you choose for the feedback option (or vice versa)?
I also want to know what X2 is for. Do you need to connect an external charger, or does the L200C feature an inbuilt battery charger that automatically changes to trickle charging when the voltage is high enough? And how do you connect it? Are you supposed to switch the positive side of the battery between X2-2 and X2-3 ?
Some connections are very simple.. X1 is for the power supply, X5 is for the motor, X3 connects to X6 on the adjustment board. But I don't get what X4 is for.
JP2 was to choose between feedback and capacitors, right? But which position is which? And can they be combined, or is it possible to eliminate some parts when you choose for the feedback option (or vice versa)?
I also want to know what X2 is for. Do you need to connect an external charger, or does the L200C feature an inbuilt battery charger that automatically changes to trickle charging when the voltage is high enough? And how do you connect it? Are you supposed to switch the positive side of the battery between X2-2 and X2-3 ?
SisterOfMercy said:
In order:
X4 connects the status indicator LED (I've provided blue in the kit, you can use any colour you like).
JP2 is indeed the feedback jumper. Briefly, jumper forward (towards board edge) is with feedback, jumper rearwards plus a whole bunch of components removed is no feedback. The number of capacitors used is up to you, further explanantion in build notes. BTW yes there was originally a JP1 but I replaced it with the switches as below and forgot to change the number back.
X1connects the board to the power supply, X2 connectsthe board to battery via a couple of switches. Connect X2-1 directly to battery negative. Connect X2-2 to an SPST switch, then to battery positive. This is the on/off switch when operating on battery. Connect X2-3 to a separate SPST switch, then to battery positive. This is the battery charge switch.
Both these switches are provided in the kit. I recommend mounting the switches so they are physically reversed from one another, so that both switches down (up in USA) is motor on / no charge, both switches up (down in USA) is motor off, battery charge. The reason for using two switches instead of one dpst switch is so that you can run with the battery charger on if wanted but more importantly so that you can switch to motor off / no charge if you disconnect or turn off the power supply. This prevents the battery draining through the charger circuit.
help with maxon DC motor
Hi Mark,
I read your very interesting pages and I see you know a lot about maxon motors. I want to ask some question.
My actual TT is made using the Linn Sondek platter, bearing motor (AC) and pulley. Many years ago I sold the chassis and I mounted them in a system without suspensions using massive black italian granite (working marble/granite is my job). I had big sonic improvement Now I would like to upgrade the motor and use your driver circuit.
The driving platter of the Sondek is about 165mm, using a 7mm pulley I need 785rpm (for 33 record). I have a Maxon Swiss DC motor (0--24Vdc). I wonder wehether this speed (785rpm) is optimal for this motor. I see that many DC motors are used at around 1200rpm, there is any reason for doing that? I am not an expert and I don't know how to determine the optimal speed range for the motor.
Bye for now
cukkurullo
Hi Mark,
I read your very interesting pages and I see you know a lot about maxon motors. I want to ask some question.
My actual TT is made using the Linn Sondek platter, bearing motor (AC) and pulley. Many years ago I sold the chassis and I mounted them in a system without suspensions using massive black italian granite (working marble/granite is my job). I had big sonic improvement Now I would like to upgrade the motor and use your driver circuit.
The driving platter of the Sondek is about 165mm, using a 7mm pulley I need 785rpm (for 33 record). I have a Maxon Swiss DC motor (0--24Vdc). I wonder wehether this speed (785rpm) is optimal for this motor. I see that many DC motors are used at around 1200rpm, there is any reason for doing that? I am not an expert and I don't know how to determine the optimal speed range for the motor.
Bye for now
cukkurullo
785 rpm is likely to be a reasonable speed using your 24V motor but without the specs (or at least a model number so I can look them up) I cannot tell.
It is a bit fast for 33 1/3 using the 110191 motor which is a 48V motor, it would be OK using the 110189 (36V)
There are no controllers available at this point anyway. There is a waiting list.
It is a bit fast for 33 1/3 using the 110191 motor which is a 48V motor, it would be OK using the 110189 (36V)
There are no controllers available at this point anyway. There is a waiting list.
Power Transformer
Hi Mark,
I know your getting tons of questions on the circuit, but I just have to ask about one area where there is conflicting info: the power transformer. In thread #1 Bas quotes you as saying:
But later when you discussed the charge circuit you mention a transformer of 18 volts with >500mA. The Allied transformer mentioned above is 18 volts at 250mA. I think you changed the amp requirement because of the charge circuit but I am very lame with electronic potentials. Should we in the Us order a Triad Transformer like the WDU-18-600 were we have sufficient amps; i.e. 600 mA?
Again, I am way over my head here so if you could just confirm my conclusion or point me in the right direction, I would appreciate it.
Hi Mark,
I know your getting tons of questions on the circuit, but I just have to ask about one area where there is conflicting info: the power transformer. In thread #1 Bas quotes you as saying:
But later when you discussed the charge circuit you mention a transformer of 18 volts with >500mA. The Allied transformer mentioned above is 18 volts at 250mA. I think you changed the amp requirement because of the charge circuit but I am very lame with electronic potentials. Should we in the Us order a Triad Transformer like the WDU-18-600 were we have sufficient amps; i.e. 600 mA?
Again, I am way over my head here so if you could just confirm my conclusion or point me in the right direction, I would appreciate it.
motor specs
Hi Mark,
Sorry if I am taking your time, but you are really an expert and I would like to get your help.
The model I have is the 2140.937-22.112-050 I put the specs on my space
http://www.homepages.ucl.ac.uk/~ucakpco/maxon--2140.937-22.112-050.pdf
do you think that 785rpm is ok for this? what di you think is the optimal range speed for this motor?
OK, so I will try to do your project myself with the help of some skilled friend.
Mark Thnaks al lot for what you doing, very helpfull,
Thanks again,
cukkurullo
Hi Mark,
Mark Kelly said:
Sorry if I am taking your time, but you are really an expert and I would like to get your help.
The model I have is the 2140.937-22.112-050 I put the specs on my space
http://www.homepages.ucl.ac.uk/~ucakpco/maxon--2140.937-22.112-050.pdf
do you think that 785rpm is ok for this? what di you think is the optimal range speed for this motor?
OK, so I will try to do your project myself with the help of some skilled friend.
Mark Thnaks al lot for what you doing, very helpfull,
Thanks again,
cukkurullo
Re: motor specs
You are exactly correct. If you do not intend to use the battery charger option the lower current PS is OK, but it will take too long to charge the recommended battery so I changed it.
By odd coincidence that is the very motor I used in the early stages of developing this circuit, so I know it well. (I had half a dozen left over from a project involving the design of a submersible agitator for small wine tanks).
It will perform reasonably well with this controller at any speed from about 400 rpm. BTW I think the 110191 and 110189 are superior motors, much quieter, possibly because the Alnico magnets are easier to balance. You could always build the circuit with the motor you have and upgrade to the Alnico motor later.
JRags said:
You are exactly correct. If you do not intend to use the battery charger option the lower current PS is OK, but it will take too long to charge the recommended battery so I changed it.
cukkurullo said:
By odd coincidence that is the very motor I used in the early stages of developing this circuit, so I know it well. (I had half a dozen left over from a project involving the design of a submersible agitator for small wine tanks).
It will perform reasonably well with this controller at any speed from about 400 rpm. BTW I think the 110191 and 110189 are superior motors, much quieter, possibly because the Alnico magnets are easier to balance. You could always build the circuit with the motor you have and upgrade to the Alnico motor later.
Due to a heavy workload ( the kind I get paid for ) I haven't come round to ordering the motors yet, I also thougth keeping the door open for latecomers would be a good idea. It has been.
Bottom line: Yes, there is still time for motors.
( And Norwegians can use my bank account number, and avoid PayPal.. )
Just PM me .
Bottom line: Yes, there is still time for motors.
( And Norwegians can use my bank account number, and avoid PayPal.. )
Just PM me .
Mark,
would you mind letting us know about the status of the project ... I will be out of touch for two weeks (starting mid of next week) and knowing my luck, this will be the window of opportunity to get the Paypal transaction done that is necessary to get the boards...
Thanks and best regards,
Andreas
would you mind letting us know about the status of the project ... I will be out of touch for two weeks (starting mid of next week) and knowing my luck, this will be the window of opportunity to get the Paypal transaction done that is necessary to get the boards...
Thanks and best regards,
Andreas
Bas,
I ignored the thread for a month because i had other things come up but i too would still like the board. I was on the intrested list and wasn't around for the message for us to email you our info. If boards do become avalible i would like to receive one. I emailed you my info last night.
For Pulleys i have an idea, if a person would take a hard plastic round stock and machine a hole in the middle to fit perfactly (or however you wanted to). Then mount your chunk of plastic on the motor mount motor on table and slowly crank a tool of some sort (a real basic lathe) wouldn't you get a perfactly round pully for YOUR motor no matter what the tolerences are. The dia is actually irrelivant as to being exact, this is because we have trimming screws on the controller. just within .5 mm would be good. The most important part is a perfactly round pully on the motor.
This could be done with even a file or sandpaper and time.
Just a thought
Ed Owens
I ignored the thread for a month because i had other things come up but i too would still like the board. I was on the intrested list and wasn't around for the message for us to email you our info. If boards do become avalible i would like to receive one. I emailed you my info last night.
For Pulleys i have an idea, if a person would take a hard plastic round stock and machine a hole in the middle to fit perfactly (or however you wanted to). Then mount your chunk of plastic on the motor mount motor on table and slowly crank a tool of some sort (a real basic lathe) wouldn't you get a perfactly round pully for YOUR motor no matter what the tolerences are. The dia is actually irrelivant as to being exact, this is because we have trimming screws on the controller. just within .5 mm would be good. The most important part is a perfactly round pully on the motor.
This could be done with even a file or sandpaper and time.
Just a thought
Ed Owens
That's probably not the correct way to use your Maxon motor. You'd have better luck if you took a 3mm precision pin and chucked it up in a drill motor with the plastic stock fixed to it, at least you wouldn't risk ruining the Maxon motor.fortytwo said:
Rigidity is paramount to achieving a concentric part and the Maxon motor has axial play built into it.
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