speed of stepper motor

Replies

• 

  Rifaa

  tech_vaibhav_ee

  i m using a stepper motor having specification 12 V 150 ma.. i m using uln2003 as motor driver..At present i m driving the motor at 15v but the problem is that the motor is rotating very slowly.the pulse frequency given to the motor is high enough so its not the problem..how can i increase the spedd of the stepper?
  
  some1 suggested me to increase the voltage upto almost 48v..is that a solution??
  in that case ,do i need to change my stepper driver??..the driver spec. are:
  
  uln2003 specifications:
  
  Symbol Parameter Value Unit
  VO Output voltage 50 V
  VI Input voltage (for ULN2002A/D - 2003A/D - 2004A/D) 30 V
  IC Continuous collector current 500 mA
  IB Continuous base current 25 mA
  TA Operating ambient temperature range - 20 to 85 °C
  TSTG Storage temperature range - 55 to 150 °C
  TJ Junction temperature 150 °C

  I don't think increasing the voltage will do you any good besides blowing up your driver or the motor for worse if it is under rated.
  You should increase the drive pulse frequency in order to increase speed. The stepper steps for every pulse you give, so the higher the pulse count the higher the speed, still you need to get the stepper specs in order to find out it's max speed at it's rated voltage. It won't do you any good if the motor is not designed for speed.
  Stepper are made for speed and / or torque, and fine increment movements.
  Cheers
  Rifaa
• 

  tech_vaibhav_ee

  i have tried increasing the pulse frequency but the speed doesnt go above 20 rpm...how can i check the maximum rpm of motor??
• 

  Rifaa

  tech_vaibhav_ee

  i have tried increasing the pulse frequency but the speed doesnt go above 20 rpm...how can i check the maximum rpm of motor??

  You have to see the motor spec sheet. The model is on the label of the motor. Go to their site or try googling. Can u post u'r schematics.
  Rifaa
• 

  tech_vaibhav_ee

  Low torque small size Stepper motor with 5 wires interface. Can be used in unipolar & bipolar mode for small applications. This motor is used motor taken from floppy drives.
  1.8 degree step angle. - 200 Steps per Revolution
  Holes on 4 corners for mounting
  12 V 150 ma.
  Weight 160gm
  Size 38x38x30 mm.
  
  that is all i know about the stepper.. i purchased it online a long time back and they didnt gave any other information..
• 

  Rifaa

  tech_vaibhav_ee

  Low torque small size Stepper motor with 5 wires interface. Can be used in unipolar & bipolar mode for small applications. This motor is used motor taken from floppy drives.
  1.8 degree step angle. - 200 Steps per Revolution
  Holes on 4 corners for mounting
  12 V 150 ma.
  Weight 160gm
  Size 38x38x30 mm.
  
  that is all i know about the stepper.. i purchased it online a long time back and they didnt gave any other information..

  😔 too bad. Your motor is not designed for high speed but rather precisions. u know data read and writing on magnetic discs
  
  U need a bigger one 😁
• 

  coolsank

  if you require more speed, i would suggest you go for dc motors. they have high rpm levels and dont require complex circuitry to run them......
• 

  tech_vaibhav_ee

  Rifaa

  😔 too bad. Your motor is not designed for high speed but rather precisions. u know data read and writing on magnetic discs
  
  U need a bigger one 😁

  what does " a bigger one" means?
  
  just for my knowledge , how can we decide whether a particular motor will give high or low speed by means of its specifications??
  
  i m giving the spec. of a stepper motor,what maximum rpm do u think it will give:
  
  

  • 
    [*]Tapped Holes on 4 corners + 2 holes on body for easy mounting.
    [*]6V 500mA, 12V 1Amp in bipolar mode.
    [*]Can be used in Bipolar mode or Unipolar Mode.
    [*]Weight : 200 gm
    [*]Dimensions : 39 x 39 x 36 mm
    [*]5 mm Standard Shaft 7 mm length
    [*]6 Wire interface
    [*]Ideal for micromouse due to its low weight to torque ratio.
    [*]Wire length 150mm without 6 pin connector
    [*]Can be directly driven using #-Link-Snipped-# and #-Link-Snipped-#
• 

  tech_vaibhav_ee

  coolsank

  if you require more speed, i would suggest you go for dc motors. they have high rpm levels and dont require complex circuitry to run them......

  actually i m using the steppers for a micromouse event ...so dc motors wont work as it requires precision..and 20 rpm is too less for the bot..
• 

  tech_vaibhav_ee

  some1 please help me !!!need it badly!!
• 

  Rifaa

  tech_vaibhav_ee

  some1 please help me !!!need it badly!!

  OK let's see, Give me the model number of the current motor you have.
  2nd'ly A micro mouse means small robotic mouse tht u intend to built. am I right.
  Give me these info and I will do What I can. OK
  Rifaa
• 

  tech_vaibhav_ee

  yes a micromouse is a small bot which solves a maze using sensors and feedback program....
  i bought the motor from a online shop ..so i dont know the model no..but u can get some of the detail at the link given below:
  #-Link-Snipped-#
  
  if u want ,i can give u the exact circuitry i have used as well...
  thanks ..
• 

  Rifaa

  The maximum speed depends on many things - the load, both frictional and inertial, the attempted acceleration, the power supply, and the
  means of control. Some of these things may be out of your control due to the requirements of your application.
  Here are some design changes that you could implement
  A. Use full stepping instead of half stepping. It is not quite as smooth, but it has a small torque advantage
  B. Use current-limited chopping control instead of passive resistive power drive. The resistive drive may be OK if the supply voltage is
  extremely high, but then you would be burning up most of your power in the resistors. Switcher-regulated current control applies full power
  supply voltage until the current rises to the specified level, then it begins chopping to keep the motor from burning up. Use as high a
  power supply voltage as you can, consistent with the capabilities of the power driver circuit.
  C. Use bipolar instead of unipolar wiring, if you have a choice. Bipolar full stepping uses all the windings all the time.
  
  The motor u have is really small, My guess for mas rpm is around 150.
  Problem is the model no. given is not listed any where, which means I cannot tell you the exact RPM without checking the manufacturers literature, Unless I get my hands on that motor.
  
  Show me your motor drive schema. OK
  Rifaa
  
  
• 

  tech_vaibhav_ee

  k..i think i should go for a current chopper ic..can u suggest me one??? can i use uln2003 as a current chopper too..other optons i have for current chopper are:
  uln2803,l298,l293d...(i m not sure that all of these are choppers..please check)...
  
  ""Show me your motor drive schema. OK"
  do u want the datasheet of motor driver or the circuit diagram??
• 

  tech_vaibhav_ee

  @ rifaa
  since i m using matlab to generate pulses and parallel port to transfer these pulses to uln2003, can the problem lie there..
  i mean does the parallel port works fast enough to transfer the pulses at such high frequency??.
• 

  Rifaa

  tech_vaibhav_ee

  @ rifaa
  since i m using mathlab to generate pulses and parallel port to transfer these pulses to uln2003, can the problem lie there..
  i mean does the parallel port works fast enough to transfer the pulses at such high frequency??.

  Show me the schematics and data sheets.
  As for math lab, it's not the frequency that I am concerned, it is the pulse voltage, parallel out is voltage is quite low as I have seen, but it's been quite a while, here's the deal, give me the details above and also the parallel port pulse waveform if u can measure it, I need the voltage values and your connection details, then only I can figure out whether the motor is running at it's full RPM or not, and as for the driver IC's, I'll post back when I get to look at the data sheets of these hybrids that I have, mean time give me the details
• 

  tech_vaibhav_ee

  k..i m giving the exact schematic and code i have used:
  ... i m using matlab to write the code and and it is being transferred thru parallel port.
  
  ...uln2003 is the stepper driver..rating of the driver are:
  Symbol Parameter Value Unit
  VO Output voltage 50 V
  Vi Input voltage 30 V
  IC Continuous collector current 500 mA
  IB Continuous base current 25 mA
  
  ....i m using 4+1(common) wire stepper motor(unipolar mode)..spec. of motor are:
  
  Low torque small size Stepper motor with 5 wires interface. Can be used in unipolar & bipolar mode for small applications. This motor is used motor taken from floppy drives.
  * 1.8 degree step angle. - 200 Steps per Revolution
  * Holes on 4 corners for mounting
  * 12 V 150 ma.
  * Weight 160gm
  * Size 38x38x30 mm.
  * Can be directly driven using AVR 40 Pin Rapid Robot controller board and Dual Motor Driver (Electronic 5 Amp)
  
  ....connections(for one motor) are as follows:
  / d0-d3 data pins of parallel port are connected to input pins 1-4 of stepper driver
  /corresponding output pins of driver,i.e 16-13 are connected to 4 wires of motor..
  /pin 8 is grounded..
  /pin 9 is given a voltage of 15v(i have tested this voltage for a range of 6-23v)...
  /common wire of motor is also given 15v..(please refer the datasheet of uln2003 for pin conf.)
  
  the code used in matlab is:
  parport= digitalio('parallel','LPT1');
  
  addline(parport, 0:7, 'out') ;
  i=0.1;
  
  while(i>.01)
  
  putvalue(parport,1);
  
  pause(i);
  
  putvalue(parport,2)
  
  pause(i);
  
  putvalue(parport,4);
  
  pause(i);
  
  putvalue(parport,8);
  
  pause(i);
  i=i-.001;
  
  end
  while(1)
  putvalue(parport,1);
  
  pause(i);
  
  putvalue(parport,2);
  
  pause(i);
  
  putvalue(parport,4);
  
  pause(i);
  
  putvalue(parport,8);
  
  pause(i);
  end
  ...in this code , i have accelerated the motor from 3 rpm to 30 rpm,but the max rpm is 20 only..
• 

  Rifaa

  @ #-Link-Snipped-#
  
  
  First of all the stepper you have can deliver more than 100 RPM, it is small and precise, since it gives 200 steps per Rev. Please note that is will operate at it's peak at the rated Voltage which is 12V @ no less than 150mA.
  
  As for the drivers the ULN2003, L293D are High current High Voltage drivers capable of handling Inductive loads such as motors, they are not specially design for just driving steppers, it can drive any inductive load. They just general purpose drivers used in many applications.
  The L298 U said is a H bridge Driver which can Drive, Motors in both ways, or even brake, brush less DC motors at high speed/ torque. It can be implemented to drive steppers but needs additional components as pulse steering circuits.
  
  I have been away from PC control aps for a few years and lost touch on most of the pro grammes I have used and since I have been on field work for around 15 years, I can very well built anything out of crap ...u know what I mean and I always built self contained units, like the drivers, motor, servos and limit switches and sensors, and mostly RC. Never did any rough or design work on a PC then. Now I am back and catching up, with the design and art work concepts of these bot's and all .. hehehe
  
  Any ways, I see tht you have wired the bot to the parallel port, right.
  And the stepper is wired in unipolar mode..
  
  Q 1. tell me does the motor make any sort of noise and vibration when the you reach your maximum RPM?
  Q 2. Are feeding half step or full steps
  Q 3. Are trying to rev up the motor instantly. say max speed and switch on.
  Q 4. Did you try the bipolar mode to get higher RPM.
  Post back
• 

  Ashraf HZ

  Ah, sorry for the interruption. Since this motor was explicitly stated as taken from floppy disk drives, it should be capable of a speeds of up to 300 rpm 😀
• 

  Rifaa

  ash

  Ah, sorry for the interruption. Since this motor was explicitly stated as taken from floppy disk drives, it should be capable of a speeds of up to 300 rpm 😀

  I agree 😉
• 

  tech_vaibhav_ee

  Rifaa

  @ #-Link-Snipped-#
  
  
  First of all the stepper you have can deliver more than 100 RPM, it is small and precise, since it gives 200 steps per Rev. Please note that is will operate at it's peak at the rated Voltage which is 12V @ no less than 150mA.
  
  As for the drivers the ULN2003, L293D are High current High Voltage drivers capable of handling Inductive loads such as motors, they are not specially design for just driving steppers, it can drive any inductive load. They just general purpose drivers used in many applications.
  The L298 U said is a H bridge Driver which can Drive, Motors in both ways, or even brake, brush less DC motors at high speed/ torque. It can be implemented to drive steppers but needs additional components as pulse steering circuits.
  
  I have been away from PC control aps for a few years and lost touch on most of the pro grammes I have used and since I have been on field work for around 15 years, I can very well built anything out of crap ...u know what I mean and I always built self contained units, like the drivers, motor, servos and limit switches and sensors, and mostly RC. Never did any rough or design work on a PC then. Now I am back and catching up, with the design and art work concepts of these bot's and all .. hehehe
  
  Any ways, I see tht you have wired the bot to the parallel port, right.
  And the stepper is wired in unipolar mode..
  
  Q 1. tell me does the motor make any sort of noise and vibration when the you reach your maximum RPM?
  Q 2. Are feeding half step or full steps
  Q 3. Are trying to rev up the motor instantly. say max speed and switch on.
  Q 4. Did you try the bipolar mode to get higher RPM.
  Post back

  
  ans1. well i did the testing on the motor a few days back ..so i dont remember exactly...i will be making the complete circuit today and would test it...i would tell u all the observations tomorrow..if u want me to test something else also..please tell me..
  
  a2. full steps.
  a3. no, i maccelerating the motor slowly..u can see it from the code i hav given too..i m acc. the motor from 3 rpm to 30 rpm..(although the max. rpm is 20)
  
  a4. no i didnt go for bipolar mode..i thought that bipolar mode is for higher torque but max. rpm is attained in unipolar mode..
  
  its good to hear that the max. rpm can be upto 300..but if can help me get it to even 60 or above , it would be gud for me...
  
  meanwhile, should i go for uln2803 for current chopper..please tell me about the current chopper asap as i need to order it frm some other place and it takes upto a week before the order arrives..
• 

  Rifaa

  ULN 2803 is the same as driver arrays (ULN2003).
  The Problem lies in your driving pulses. the pulse width should be precise in order to turn the motor from one step to the next. If you do not understand the stepper rotating details, tell me and I'll forward U the theory
• 

  tech_vaibhav_ee

  (postedby rifaa). tell me does the motor make any sort of noise and vibration when the you reach your maximum RPM?
  i drove the motor at 3 different voltages:
  at 5v: there was no noise or vibrations..the current in the coil was 50ma..
  at 10v: no noise and a bit of vibration..current:120ma
  at 15v: almost no noise but a lot of vibration... current:150ma
  
  (posted by rifaa)The Problem lies in your driving pulses. the pulse width should be precise in order to turn the motor from one step to the next. If you do not understand the stepper rotating details, tell me and I'll forward U the theory.
  by pulse width,do u mean the pauses i m giving in the code??
• 

  engrasad

  why don't you use a servo motor instead?
• 

  Rifaa

  tech_vaibhav_ee

  (postedby rifaa). tell me does the motor make any sort of noise and vibration when the you reach your maximum RPM?
  i drove the motor at 3 different voltages:
  at 5v: there was no noise or vibrations..the current in the coil was 50ma..
  at 10v: no noise and a bit of vibration..current:120ma
  at 15v: almost no noise but a lot of vibration... current:150ma
  
  (posted by rifaa)The Problem lies in your driving pulses. the pulse width should be precise in order to turn the motor from one step to the next. If you do not understand the stepper rotating details, tell me and I'll forward U the theory.
  by pulse width,do u mean the pauses i m giving in the code??

  Ah that's what I am talking about, the Vibrations. 😡
  
  Quit math lab and built a stepper driver circuit. The pulse width counts in stepper driving, specially the mode u are trying, the rotor rotation and salient pole line up timing causes vibration, and the motor just won't speed up to it's max
• 

  Megha Diggavi

  Hi...
  Please give me the details about 'micromouse events'.& also give the other applications of stepper motor.
• 

  Rifaa

  "micromouse" 😕 what the heck is that?
  
  as for stepper apps, what kinda apps you want 😕
• 

  jarniel

  instead of using stepper motor you can used servo motor that can vary the speed by increasing and decreasing the voltage input vice versa. you can use it forward and reverse direction.correct me if im wrong
  
  here is the detail:
  
  A stepper motor (or step motor) is a Brushless Dc Electric Motor, synchronous Electric Motor that can divide a full rotation into a large number of steps. The motor's position can be controlled precisely, without any feedback mechanism (see Open Loop control). Stepper motors are similar to Reluctance Motor (which are very large stepping motors with a reduced pole count, and generally are closed-loop commutated.)
  
  Stepper motors operate differently from normal DC motors, which rotate when voltage is applied to their terminals. Stepper motors, on the other hand, effectively have multiple "toothed" electromagnets arranged around a central gear-shaped piece of iron. The electromagnets are energized by an external control circuit, such as a micro controller. To make the motor shaft turn, first one electromagnet is given power, which makes the gear's teeth magnetically attracted to the electromagnet's teeth. When the gear's teeth are thus aligned to the first electromagnet, they are slightly offset from the next electromagnet. So when the next electromagnet is turned on and the first is turned off, the gear rotates slightly to align with the next one, and from there the process is repeated. Each of those slight rotations is called a "step," with an integral(complete number) number of steps making a full rotation. In that way, the motor can be turned by a precise angle.
  
  SERVO
  Servo motors are used in closed loop control systems in which work is the control variable, Figure 9. The digital servo motor controller directs operation of the servo motor by sending velocity command signals to the amplifier, which drives the servo motor. An integral feedback device (resolver) or devices (encoder and tachometer) are either incorporated within the servo motor or are remotely mounted, often on the load itself. These provide the servo motor's position and velocity feedback that the controller compares to its programmed motion profile and uses to alter its velocity signal. Servo motors feature a motion profile, which is a set of instructions programmed into the controller that defines the servo motor operation in terms of time, position, and velocity. The ability of the servo motor to adjust to differences between the motion profile and feedback signals depends greatly upon the type of controls and servo motors used. See the servo motors Control and Sensors Product section.
  Three basic types of servo motors are used in modern servosystems: ac servo motors, based on induction motor designs; dc servo motors, based on dc motor designs; and ac brushless servo motors, based on synchronous motor designs.
• 

  urgull

  Interface of stepper motor with microcontroller 8051 or PIC 16f877 with circuit diagram and explanations and source code can be found here.
  #-Link-Snipped-# or on this pages
  
  #-Link-Snipped-#