Assignment Stepper Motor

5/12/2018 Assignment Stepper Motor - slidepdf.com

http://slidepdf.com/reader/full/assignment-stepper-motor 1/17

Assignment:Assignment:

Stepper Motor and itsStepper Motor and its

Control.Control.

Submitted To:Submitted To:

Sir Usman GullSir Usman Gull

Department of Technology.Department of Technology.

The University of Lahore.The University of Lahore.



Submitted bySubmitted by

Group Members:Group Members:

1..Ehtesham Ali (TE-htesham Ali (TE-

327227)27227)

2.2.

Hassan Ali (TE-327216)Hassan Ali (TE-327216)

3.3. Qumar-ul-islam (ET-107203)Qumar-ul-islam (ET-107203)

4.4. Muhammad Rais (ET-327216)Muhammad Rais (ET-327216)

5.5. Mubasher Ahmed (ET-327203)Mubasher Ahmed (ET-327203)



DC STEPPER MOTORSDC 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



Fundamentals of Fundamentals of

operationoperation

• Stepper motors effectively have multiplStepper motors effectively have multipl"toothed" electromagnets arranged"toothed" electromagnets arrangedaround a central gear-shaped piece of around a central gear-shaped piece of

iron. The electromagnets are energizediron. The electromagnets are energizedby an external control circuit, such as aby an external control circuit, such as amicrocontroller microcontroller ..

• To make the motor shaft turn, first, oneTo make the motor shaft turn, first, oneelectromagnet is given power, whichelectromagnet is given power, whichmakes the gear's teeth magneticallymakes the gear's teeth magneticallyattracted to the electromagnet's teeth.attracted to the electromagnet's teeth.

http://en.wikipedia.org/wiki/Microcontroller





the first electromagnet, they arethe first electromagnet, they are

slightly offset from the nextslightly offset from the next

electromagnet.electromagnet.

• when the next electromagnet is turnedwhen the next electromagnet is turnedon and the first is turned off, the gear on and the first is turned off, the gear rotates slightly to align with the nextrotates slightly to align with the next

one, and from there the process isone, and from there the process isrepeated.repeated.

• Each of those slight rotations is calledEach of those slight rotations is calleda "step", with an integer number of a "step", with an integer number of

steps making a full rotation.steps making a full rotation.• In that way, the motor can be turned byIn that way, the motor can be turned by

a precise angle.a precise angle.







• Voltage RatingVoltage Rating– provides desired torqueprovides desired torque

• Resistance-per-windingResistance-per-windingdeterminesdetermines– the current draw of the motor the current draw of the motor

– Maximum operating speedMaximum operating speed

• Degrees per StepDegrees per Step– Sets the number of degrees theSets the number of degrees the

shaft will rotate for each full stepshaft will rotate for each full step



UNIPOLAR STEPPERUNIPOLAR STEPPER

MOTORMOTOR

• Relatively easy to controlRelatively easy to control

• simple 1-of-'n' counter circuit cansimple 1-of-'n' counter circuit can

generate the proper stepping sequencegenerate the proper stepping sequence

• 1 transistor per winding1 transistor per winding




MOTORMOTOR

• two center-tapped coilstwo center-tapped coils

• represents the connection of a 4represents the connection of a 4

-phase unipolar stepper motor -phase unipolar stepper motor




MOTORMOTOR

• 6 wires with a center tap on each of two6 wires with a center tap on each of two

coilscoils



IDENTIFYING WIRESIDENTIFYING WIRES

• Check make and model to see if Check make and model to see if wire colour code is availablewire colour code is available

• Observe the wires to see if youObserve the wires to see if youcan identify groups of 3 wirescan identify groups of 3 wires

• Measure resistance betweenMeasure resistance between

wireswires• Wire with lowest resistance is Wire with lowest resistance ispower wirepower wire



IDENTIFYING WIRESIDENTIFYING WIRES

• 6 wire motors6 wire motors

– Groups of 3 wiresGroups of 3 wires

– 1 power & 2 signal1 power & 2 signal• 5 wire motors5 wire motors

– 1 power & 4 signal1 power & 4 signal

wireswires

• power wire haspower wire has

lowestlowest

resistance toresistance to

the othersthe others



CONTROL PROGRAMCONTROL PROGRAM

• Once wires identified and connected to theOnce wires identified and connected to thecircuit: a program is needed to run thecircuit: a program is needed to run themotor motor

• Example Turing Program:Example Turing Program:looploop

parallelput (1)parallelput (1)

delay (500)delay (500)


delay (500)delay (500)parallelput (4)parallelput (4)




end loopend loop



STEPPER MOTORSTEPPER MOTOR

CONTROLCONTROL

• 4 signal wires fired in the correct4 signal wires fired in the correct

sequence will turn the motor sequence will turn the motor



DISADVANTAGESDISADVANTAGES

• Resonance effects and relatively longResonance effects and relatively longsettling timessettling times

• Rough performance at low speed unless aRough performance at low speed unless a

microstep is usedmicrostep is used• Liability to undetected position loss as aLiability to undetected position loss as a

result as a result of operating open-loopresult as a result of operating open-loop

• Consume current regardless of loadConsume current regardless of load

• Losses at speed are relatively high and canLosses at speed are relatively high and cancause excessive heating and they arecause excessive heating and they arefrequently noisy (especially at high speedsfrequently noisy (especially at high speeds))



ADVANTAGESADVANTAGES

• Low costLow cost

• Work in almost any environment Work in almost any environment

• RuggedRugged• Simplicity in constructionSimplicity in construction

• High reliabilityHigh reliability

• No maintenanceNo maintenance

• No feedback components are neededNo feedback components are needed

• Inherently more failsafe than servo motInherently more failsafe than servo mot



THE ENDTHE END

THANKSTHANKS

Documents

Assignment Stepper Motor