SUBMITTED TO

ENGR. ZAFAR MEHMOOD

GROUP MEMBERS

TAYYAB KHAN (13EE66)MUNEEB TAHIR (13EE64)AKTHAR ALI (13EE62)

Stepper motor as a Generator

WHAT IS A STEPPER MOTOR?

Dc motors move in discrete stepsMultiple coilsArranged in group called phasesMotor rotates one step by

energizing

WHEN TO USE A STEPPER MOTOR

A stepper motor can be a good choice whenever controlled movement is required.

They can be used to advantage in applications where you need to control rotation angle, speed and position.

STEPPER MOTOR CHARACTERISTICS• Stepper motors are constant power devices.• As motor speed increases, torque decreases.• Steppers exhibit more vibration than other

motor types.• This vibration can become very bad at some

speeds and can cause the motor to lose torque.

ConstructionMain Components

• Stator• Rotor• Coils• Outside casing

Principle of stepper motor• A stepper motor is an electromechanical

device.• It converts electrical pulses into discrete

mechanical movements. • The shaft or spindle of a stepper motor rotates

in discrete step increments when electrical command pulses are applied to it.

Principle of stepper motorThe motors rotation has several direct relationships to

these applied input pulses. The speed of the motor shafts rotation is directly

related to the frequency of the input pulses.The length of rotation is directly related to the

number of input pulses applied.

Stepper Motor as a GeneratorConnected a bridge rectifier to the motorIt converts Ac to pulsating dc supplyCapacitor connected to the bridge rectifierIt converts pulsating dc to pure dc.

Advantages • Very reliable.• There are no contact brushes in the

motor. • Excellent response to

starting/stopping/reversing.

DISADVANTAGES

• Resonances can occur if not properly controlled.• Not easy to operate at extremely high speeds.

APPLICATIONS

PrinterCopy MachinesAutomatic typewritersLaser Cutting