STEPPER MOTOR A stepper motor is a “pulse- driven” motor that changes the angular position of the rotor in “steps”

TYPES OF STEPPER MOTOR  VARIABLE RELUCTANCE STEPPER MOTOR  PERMANENT MAGNET STEPPER MOTOR  HYBRID STEPPER MOTOR

VR STEPPER MOTOR

Variable Reluctance ( VR) stepper motor  Wound Stator poles Single Stack Multiple Stack – smaller step angle  Rotor poles – ferromagnetic material  Direction – stator current polarity  Reluctance of the magnetic circuit formed by rotor and stator teeth varies with angular position of the rotor

Modes of operation –VR type  1-phase ON – full step operation  2-phase ON  Half-step – alternate 1-phase & 2-phase mode  Micro stepping

1-PHASE ON – FULL STEP OPERATION

2-PHASE ON MODE

HALF-STEP – ALTERNATE 1-PHASE & 2-PHASE MODE

HALF STEP OPERATION

VR – MULTI STACK

 Stepangle β = ((Ns-Nr)/Ns*Nr) *360= 360/m*Nr N s – No. of Stator poles (teeth) N r – No. of Rotor poles (teeth) m - No. of stator phases  Resolution = No. of steps/revolution = 360 o /β

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