New and Original YASKAWA 100W 200V AC SERVO MOTOR SGM-01A312B Made in Japan

 
 
 
OTHER SUPERIOR PRODUCTS

SIMILAR PRODUCTS

PULSE RATE
Obviously, the smaller the step angle is, the more accurate the motor. But the number of pulses stepper motors can accept per second has an upper limit. Heavy-duty steppers usually have a maximum pulse rate (or step rate) of 200 or 300 steps per second, so they have an effective top speed of one to three revolutions per second (60 to 180 rpm). Some smaller steppers can accept a thousand or more pulses per second, but they don’t usually provide very much torque and aren’t suitable as driving or steering motors.

Note that stepper motors can’t be motivated to run at their top speeds immediately from a dead stop. Applying too many pulses right off the bat simply causes the motor to freeze up. To achieve top speeds, you must gradually accelerate the motor. The acceleration can be quite swift in human terms. The speed can be one-third for the first few milliseconds, two thirds for the next few milliseconds, then full blast after that.

RUNNING TORQUE
Steppers can’t deliver as much running torque as standard DC motors of the same size and weight. A typical 12-volt, medium-sized stepper motor may have a running torque of only 25 oz-in. The same 12-volt, medium-sized standard DC motor may have a running torque that is three or four times more.

However, steppers are at their best when they are turning slowly. With the typical stepper, the slower the motor revolves, the higher the torque. The reverse is usually true of continuous DC motors. Fig. 19.5 shows a graph of the running torque of a medium-duty, unipolar 12-volt stepper. This unit has a top running speed of 550 pulses per second. Since the motor has a step angle of 1.8°, that results in a top speed of 2.75 revolutions per second (165 rpm).