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ELECTRIC MOTOR CONTROLS . b; d; ?: E: ^* k3 D9 o
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Once the proper motor is selected, understanding the many various control devices available and
: x9 J/ G# c q4 h- n- o7 [their uses and limitations becomes an important part related to reliable operation and protection of ( N9 [' a) V' I; y
the motor and the personnel using the motor.
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Motor Control Topics ; p7 w7 H; Z% H$ F7 b( _
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There are four major motor control topics or categories to consider. Each of these has several 6 Q7 f$ q9 y* B, R+ D' h2 W
subcategories and sometimes the subcategories overlap to some extent. Certain pieces of motor
' i* v5 n% a3 Y% f0 _control equipment can accomplish multiple functions from each of the topics or categories.
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8 z7 l& J: G% P3 ]# T4 g* nThe four categories include: 4 Z# M3 e( z7 x* q& p) k/ O
. G- f1 O# t( l; o5 ]8 e3 O9 I4 N1) Starting the Motor
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+ Z4 @* @$ U& H8 iDisconnecting Means 3 t2 N# M( H2 z
Across the Line Starting
! d D1 [9 H. n$ fReduced Voltage Starting
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2) Motor Protection 2 i1 m/ g. Y' N+ u! w
4 @! L) {4 Z1 Y3 o3 ~Overcurrent Protection
7 A0 R! I/ m' ]3 g4 |Overload Protection % C$ B( P9 c/ L1 o1 R
Other Protection (voltage, phase, etc)
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0 C5 t7 L% V) I+ d' L3) Stopping the Motor
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Coasting $ T3 z2 w( t. O0 c- D3 h
Electrical Braking . p7 J% u* v4 _; ^1 z8 d! t
Mechanical Braking
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4) Motor Operational Control
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* l: ?4 W1 S7 {4 M6 M/ l/ ESpeed Control ; q9 }% k5 @* ~2 m' U; j
Reversing
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