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ELECTRIC MOTOR CONTROLS
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6 X. [& e4 W5 d* K: L+ I0 ?# ?- ?Once the proper motor is selected, understanding the many various control devices available and 3 N0 f: ?% S1 {! q1 b7 L$ Y
their uses and limitations becomes an important part related to reliable operation and protection of R8 T. v- Z( G" T3 b5 `6 p. D
the motor and the personnel using the motor. ; G% p) R H) ^) u. [
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Motor Control Topics
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There are four major motor control topics or categories to consider. Each of these has several
6 g* }! ]4 H6 ^. R: fsubcategories and sometimes the subcategories overlap to some extent. Certain pieces of motor 6 T4 q' H4 X& h1 s( L
control equipment can accomplish multiple functions from each of the topics or categories.
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0 U7 U7 Z$ P1 SThe four categories include: , c3 i" x0 G& Y, l3 N$ G
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1) Starting the Motor
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/ k* N( J: a% ~& QDisconnecting Means
; Z9 z' o; e) o; }( sAcross the Line Starting
# K& Z M' g1 {8 R2 u& x5 q6 XReduced Voltage Starting - I. O/ V8 ]: s4 B( ]9 I6 Q
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/ t4 I; |' l3 ^8 q* h* }2 S0 O2) Motor Protection . K* E4 w* a) X- S0 {. a L
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Overcurrent Protection
. ~; `; P& A' x6 iOverload Protection ! p( U- p7 e5 i5 B7 u
Other Protection (voltage, phase, etc)
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3) Stopping the Motor # i- Q" ~0 D, b
6 o6 x( o+ Q4 g- z) A' }Coasting
3 ]4 u$ R1 Z$ F$ e2 UElectrical Braking % f1 k2 v* @( U
Mechanical Braking ! A' `: p1 q' g: ^5 P( {" G |
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+ Y$ ]1 A" A8 N0 @9 t4) Motor Operational Control
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Speed Control ! S; J/ Y: I1 s o
Reversing
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