faulhaber 141:1 motor specifics, and genral dynamics?

Comments

• Duane C. Johnson Posts: 955

  2012-10-27 18:18 edited 2012-10-27 18:18

  Hi Loopy;

  Loopy Byteloose wrote: »

  Only thing not mentioned is the actual resolution of the encoder.

  Apparently the encoder is a low resolution type.
  Basiclly 1 pulse per revolution of the driving motor for both phase A and B, with there being 90 degrees between them which is usefull for precission quadrature speed and direction detection.
  Remember, the actual gear ratio is 140.759183:1.
  So there would be 140.759183 pulses per output revolution.
  
  Duane J
• rwgast_logicdesign Posts: 1,464

  2012-10-27 19:57 edited 2012-10-27 19:57

  @duane so ive sat down read all i could find about this motor and if it has good torque i belive itll be just fine. My biggest worry os that the blurb says 3 to 18v but the review you linked me to said is started overheating above 10vs have you had this experince?
  
  my other questions specically about this motor is how loud is it? and would how accurate is a low res encoder? would a hi res optical encoder after the gearing be pointless?
• LoopyByteloose Posts: 12,537

  2012-10-28 02:32 edited 2012-10-28 02:32

  I'd say the speed is a bit on the slow side. I would not expect it to compete in a competition that requires speed. The 140 or so signals per delivered RPM is good, but some go a lot higher. If you add more gears, this number will change again. The wheel size also changes the encoder's count as it is equal to yet another gear ratio.
  
  I am not sure that a lot higher encoder resolution is really worthwhile as you have your counters rolling over more and that would require watching them more closely for navigation purposes. This would be nice to use with the 32bit Propeller.
  
  All in all it is a good fit. I suggest you go directly to the Faulhaber site to get good information directly about their motors and encoders that are similar to what you have. I have not done it for this motor, but I did it for others and was quite pleased that they provided so much.
  
  What would be good torque. With 20ma at 6v, the best you can expect is .120 watts when 746 watts equals one horsepower. More torquey would be in the tens of watts -- say 10 - 30 watts. But those motors from Faulhaber with encoders and gears are easily over $100 USD each. EBay does sell them used at times.
  
  Regarding doing something with the final gear...
  It appears to be attached with a set screw. Once you have the motors, you can remove it and put on something else - any ratio that will work physically and provide the right speed with adequate power. But you will have to find gears somewhere else. In some case, you won't need a set screw as the torque is so low - just glue on with epoxy.
  
  And of course, as said before, the actual wheel size with change the encode rate for distance. You won't know what you have until you actually finished building it.
  
  Also can anyone with experience with these motors tell me how loud they are?
  I give up. At 0.120 watt of power, do you really expect a lot of noise? I can barely hear those silly piezoelectric speakers that Parallax provides. Even a 0.5watt 8ohm speaker is rather useless. So think hifi - if it isn't 3 or more watts, it isn't loud. Over 15 watts is way too loud.
• Duane C. Johnson Posts: 955

  2012-10-28 06:10 edited 2012-10-28 06:10

  rwgast_logicdesign wrote: »

  @duane so I've sat down read all i could find about this motor and if it has good torque i believe itll be just fine. My biggest worry is that the blurb says 3 to 18v but the review you linked me to said is started overheating above 10vs have you had this experience?
  
  my other questions specifically about this motor is how loud is it? and would how accurate is a low res encoder? would a hi res optical encoder after the gearing be pointless?

  I only run it on 5V so it runs pretty cool.
  I'm using it in a solar tracking heliostat application so it hardly turns at all.
  It has a tiny cog belt output, I have some of these tiny belts, for a further gear reduction of 12:1.
  
  Torque? I don't have a good way of measuring it. I can easily stall it with my thumb.
  Remember, this is a fairly small high precession motor.
  I'm not sure it is suitable to drive a 6" wheel directly.
  6" wheel implies a heavy car and possibly over taxing the motor.
  
  I can hardly hear the thing run.
  
  The encoder is low resolution at 1 pulse per motor revolution.
  140.759183:1 * 12:1 = 1689.110196:1 on the output is adequate for my purposes.
  
  Duane J