This document summarizes a seminar presentation on stepper motors. It describes the basic components and operating principles of stepper motors, including the different types (permanent magnet, variable reluctance, and hybrid). It also discusses identifying motor wires, the differences between full-step and half-step motors, provides an example of stepper motor specifications, and lists some common applications of stepper motors.

1. A
SEMINAR ON
“STEPPER MOTOR”
BACHELOR OF TECHNOLOGY
IN
ELECTRICAL & ELECTRONICS ENGINEERING
SUBMITTED
BY
PANKAJ CHAUDHARY
R.N. - 24823
UNDER THE SUPERVISION OF
ARUNESH DUTT
ASST. PROFESSOR
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING
SANJAY GANDHI INSTITUTE OF ENGINEERING & TECHNOLOGY
NEHRU GRAM BHARATI UNIVERSITY, ALLAHABAD

2. CONTENTS
 WHAT ’S A STEPPER MOTOR?
 TYPES OF STEPPER MOT
* PERMANENT MAGNET
* VARIABLE RELUCTANCE
* HYBRID
 IDENTIFYING WIRES
 FULL STEPPER MOTOR
 HALF STEPPER MOTOR
 STEPPER MOTOR EXAMPLE
 APPLICATIONS
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3. What’s a Stepper Motor?
A stepper motor is a brushless
electric motor that has the ability
to divide one rotation into
different steps. Unlike the
common DC brush motors, a
stepper motor uses
electromagnets to make the
motor shaft turn.
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4. Stepper Motors
 Some stepper motor uses permanent magnets. Some
stepper motors do not have magnets and instead use the
basic principles of a switched reluctance motor. The
stator is similar but the rotor is composed of a iron
laminates.
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5. DC STEPPER MOTORS
 Stepping motors are electric
motors without commutators
 Commutation is handled
externally by the motor
controller
 Controller charges opposite
coils attracting the center rotor
magnets
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6. DC STEPPER MOTORS
 Voltage Rating
 provides desired torque
 Resistance-per-winding
determines
 the current draw of the motor
 Maximum operating speed
 Degrees per Step
 Sets the number of degrees the shaft
will rotate for each full step
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7. Types of Stepper Motors
 Permanent Magnet
 Variable Reluctance
 Hybrid
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8. Permanent Magnet Motors
Permanent magnet motors use a permanent magnet (PM) in
the rotor and operate on the attraction or repulsion
between the rotor PM and the stator electromagnets
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9. Variable Reluctance Motors
Variable reluctance (VR) motors have a plain iron
rotor and operate based on the principle that
minimum reluctance occurs with minimum gap,
hence the rotor points are attracted toward the
stator magnet poles.
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10. Hybrid Motors
Hybrid stepper motors are named because they use a
combination of PM and VR techniques to achieve
maximum power in a small package size.
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11. IDENTIFYING WIRES
 Check make and model to see if wire colour code is
available.
 Observe the wires to see if you can identify groups of 3
wires.
 Measure resistance between wires .
 Wire with lowest resistance is power wire.
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12. Full Stepper Motor
 The rotor of a permanent magnet stepper motor consists
of permanent magnets and the stator has two pairs of
windings. Just as the rotor aligns with one of the stator
poles, the second phase is energized. The two phases
alternate on and off and also reverse polarity. There are
four steps. One phase lags the other phase by one step.
This is equivalent to one forth of an electrical cycle or
90°.
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13. Half Stepper Motor
 The commutation sequence for a half-step stepper
motor has eight steps instead of four. The main
difference is that the second phase is turned on before
the first phase is turned off. , sometimes both phases are
energized at the same time. During the half-steps the
rotor is held in between the two full-step positions. A
half-step motor has twice the resolution of a full step
motor. It is very popular for this reason.
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14. Stepper Motor example
 From Sherline CNC milling machine:
 Step angle: 1.8°
 Voltage: 3.2 V
 Holding torque: 0.97 N-m
 Rotor inertia: 250 g-cm2
 Weight: 1.32 lb (0.6 Kg.)
 Length: 2.13" (54 mm)
 Power output = 3W
 Precision stepper motor: 0.02° /step, 1 rpm, 3W
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15. Applications
These are examples of OSM's (optimal stepper
motor) Stepper Motor Application, Stepper motors
are used in a wide variety of applications in industry,
including computer peripherals, business machines,
motion control, and robotics etc.
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16. THANK YOU
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