A

SEMINAR ON

“STEPPER MOTOR”BACHELOR OF TECHNOLOGY

IN

ELECTRICAL & ELECTRONICS ENGINEERINGSUBMITTED

BY

PANKAJ CHAUDHARY R.N. - 24823

UNDER THE SUPERVISION OF

ARUNESH DUTT ASST. PROFESSOR

NEHRU GRAM BHARATI UNIVERSITY, ALLAHABAD

DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING SANJAY GANDHI INSTITUTE OF ENGINEERING & TECHNOLOGY

CONTENTSWHAT ’S A STEPPER MOTOR?TYPES OF STEPPER MOT * PERMANENT MAGNET * VARIABLE RELUCTANCE * HYBRIDIDENTIFYING WIRES FULL STEPPER MOTORHALF STEPPER MOTORSTEPPER MOTOR EXAMPLEAPPLICATIONS

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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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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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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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DC STEPPER MOTORSVoltage Rating

provides desired torque

Resistance-per-winding determinesthe current draw of the motorMaximum operating speed

Degrees per StepSets the number of degrees the

shaft will rotate for each full step

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Types of Stepper Motors

Permanent MagnetVariable ReluctanceHybrid

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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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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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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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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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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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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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Stepper Motor exampleFrom Sherline CNC milling machine:Step angle: 1.8°Voltage: 3.2 VHolding torque: 0.97 N-mRotor inertia: 250 g-cm2

Weight: 1.32 lb (0.6 Kg.)Length: 2.13" (54 mm)Power output = 3WPrecision stepper motor: 0.02° /step, 1 rpm,

3W

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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.

Applications

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THANK YOU

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