## 30/03/2020

### Stepper Motor Interview Question Answer - 1

Give the reason behind the motor name as stepper motor or step motor.

Stepper motor

It is an electrical motor in which rotor rotates through fixed angle in response to each input current pulse.

State the different types of stepper motor.

Types of stepper motor

Variable reluctance (VR) stepper motor

Permanent magnet (PM) stepper motor

Hybrid stepper motor

Explain the term : Step angle

Step angle

It is angle through the motor shaft rotates for each input pulse.

Explain the term : Resolution

Resolution

It is defined as the number of steps needed to complete one revolution of the motor shaft. Higher the resolution, greater the accuracy of the stepper motor.

Define : Step rate

Step rate

It is defined as the number of steps a shaft rotates in a given specified period.

State the meaning of slewing in the stepper motor.

Slewing

The stepper motor operation at high speed is called as slewing.

Explain the term : Torque gradient or stiffness

It is defined as the ratio of change in holding torque for particular change in shaft position when the stepper motor is in energized condition.

On which factors the Step angle of the stepper motor depends?

The step angle of the stepper motor depends upon stator and rotor poles and number of phases.

Explain the term : Full step operation , Half step operation

Full step operation

The operation of the stepper motor with only one phase energized at a time, other two phase remains in the non – energized condition.

Half step operation

The operation of the stepper motor with only one phase energized at a time, other two phase remains in the non – energized condition.

The second time two phase energized at a time while remaining one phase in the non – energized condition. Therefore, it is combination of one phase ON and two phase ON mode operation.

Which type of stator and rotor does the variable reluctance stepper motor consist of?

VR stepper motor

Stator : It has wound stator salient poles.

Rotor : It consists of salient poles.

Which type of stepper motor operation has greater holding torque? Single phase ON or two phase ON

Two phases ON

Explain the term : Micro – stepping

Micro – stepping

It is stepping mode in which two phases simultaneously on but at the same time the currents in the two phases deliberately made unequal.

State the micro stepping application of the stepper motor.

The micro stepping stepper motor provides low speed operation and high resolution. It is used in printing application.

State the function of the viscous damping.

Viscous damping

The function of the viscous damping is to provide friction torque proportional to speed.

Whether any stalling problem in the stepper motor?

No

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