In: Electrical Engineering
Question 1
A stepper motor advances 2.5̊ per step.
How many pulses are needed to complete 3 revolutions?
Explain what is meant by normal drive, wave drive and half-step drive.
Why is viscous damping employed in stepper motors?
When a stepper motor is ramping or slewing properly, every pulse corresponds to a precise angle of rotation. True or false?
1) Given, stepper motor advances 2.50 per step.
Hence 2.50 = 1 pulse
n pulses =
Therefore, no: of revolutions needed to complete 3 revolutions
So, 432 pulses are needed for the stepper motor to complete 3 revolutions.
Half - step drive:
Half-step is the mode of operation in which the drive alternate between normal wave drive and creates a half-step of rotation.
Wave drive:
In this drive method, only a single phase is activated at a time. It has the same number of steps as the full-step drive, but the motor will have significantly less torque than rated. It is rarely used.
Normal drive:
Normal drive is the mode of operation of stepper motor in which two sets of field coils are energized simultaneously to cause one step of rotation
Damping in stepper motor:
In a stepper motor, the damping should respond to changes in velocity. this is achieved by using viscous damping.
A straightforward way to control resonance is to deliberately add damping to the system.
It is possible to introduce damping which responds to changes in velocity by using a viscous coupled inertia damper (VCID). This consists of an inertial mass which is free to rotate on the shaft of the stepper motor but is coupled to it via a viscous substance. At a steady speed, the shaft and mass will rotate at the same velocity, but if the motor changes speed, the inertia of the mass will introduce damping.
True or False: Yes, when a stepper motor is ramping or slewing properly, every pulse corresponds to a precise angle of rotation.