stepper motor and its types

8/20/2019 Stepper Motor and its types

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1. What is a stepper motor

2. Internal structure of stepper motor

3. Printed circuit board (PCB)

4. Ho stepper motor or!s"#. $%pes of stepper motor


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& brushless' s%nchronous motor hich

diides a full rotation into a no. of steps

It rotates in discrete step anles $he% are manufactured ith steps per

reolution of 12' 24' *2' 144' 1+,' 2,,resultin in steppin anles of 3,' 1#' #'

2.#' 2 and1.+ derees per step It can be controlled ith or ithout

feedbac!


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$he stator also contains teeth hich are

electromanetic in nature. -er% tooth is surrounded b% a coil. ependin

on the polarit% of the current supplied in thecoil' the tooth can be made to behae li!e / or

0 poles.


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$he rotor is made up of a permanent manets

core ith to soft iron discs ith teeth on theperipher%. $he number of teeth decides the step anle of

the motor.

$he teeth on the front dis! form thepermanent manetic south poles hereas theteeth on the rear dis! form the permanentmanet north poles.


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$he oerall structure loo!s li!e a pair of earsstic! to each other.

$he alinment of the teeth is done in such amanner that the teeth on one disc arepositioned beteen the space in the toconsecutie teeth on the other disc and ice

ersa.


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& 0tepper motor has a stator and a rotor.

$he rotor has a permanent manet attached toit.

$he stator is made up of coils as shon in theaboe imae.

$here are eiht coils in this motor. -er% coil in the motor behaes as an

electromanet' hen the% are eneried b%electrical pulses.


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& printed circuit board (PCB) mechanicall%supports and electricall% connects electroniccomponents

It is a board that has lines and pads thatconnect arious points toether.

& PCB allos sinals and poer to be routedbeteen ph%sical deices. 0older is the metal that ma!es the electrical

connections beteen the surface of the PCB

and the electronic components. Bein metal' solder also seres as a stron

mechanical adhesie.


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$he PCB has e ires hich are connectedith the coils.

-er% pair of alternate coils is connected

toether. PCB has e output ires four ires each

connected ith to alternate coils and one forcommon ire.


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0tepper motors or! on the principle of

electromanetism. & stepper motor rotates in distinct steps

here each step is a fraction of a full circle. 0tepper motors are drien ith pulses and

one set of pulses can moe the steppermotor b% one step onl%.

$here is a soft iron or manetic rotor shaft

surrounded b% the electromanetic stators. $he rotor and stator hae poles hich ma%

be teethed or not dependin upon the t%peof stepper.


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When the stators are eneried the rotormoes to alin itself alon ith the stator

$his a% the stators are eneried in ase5uence to rotate the stepper motor


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B% construction the step motors come intothree broad classes6

1. Permanent 7anet 0tepper 2. 8ariable 9eluctance 0tepper 3. H%brid 0tep 7otor


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$he rotor and stator poles of a permanentmanet stepper are not teethed

Instead the rotor hae alternatie north andsouth poles parallel to the a:is of the rotorshaft.


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When a stator is eneried' it deelopselectromanetic poles.

$he manetic rotor alins alon themanetic eld of the stator. $he other stator is then eneried in the

se5uence so that the rotor moes and

alins itself to the ne manetic eld. $his a% eneriin the stators in a :ed

se5uence rotates the stepper motor b%:ed anles.


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$he resolution of a permanent manet

stepper can be increased b% increasinnumber of poles in the rotor or increasinthe number of phases.


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$he ariable reluctance stepper has atoothed non;manetic soft iron rotor.

When the stator coil is eneried the rotormoes to hae a minimum ap beteen thestator and its teeth.


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$he teeth of the rotor are desined so thathen the% are alined ith one stator the%et misalined ith the ne:t stator.

/o hen the ne:t stator is eneried' therotor moes to alin its teeth ith the ne:t

stator. $his a% eneriin stators in a :ed

se5uence completes the rotation of the stepmotor.


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$he resolution of a ariable reluctancestepper can be increased b% increasin the

number of teeth in the rotor and b%increasin the number of phases.


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& h%brid stepper is a combination of bothpermanent manet and the ariablereluctance.

It has a manetic teethed rotor hich betteruides manetic


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$he manetic rotor has to cups. =ne fornorth poles and second for the south poles.

$he rotor cups are desined so that that thenorth and south poles arrane in alternatiemanner.


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$he H%brid motor rotates on same principleof eneriin the stator coils in a se5uence.


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stepper motor and its types

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