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ELECTRIC MOTOR CONTROLS
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& W4 u# u+ d6 U6 o+ S0 `( gOnce the proper motor is selected, understanding the many various control devices available and
% o1 @* ^& O5 W. { \their uses and limitations becomes an important part related to reliable operation and protection of 5 r# n( D2 M+ i( q ^
the motor and the personnel using the motor.
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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
5 x$ {; u4 `4 q- \0 Tsubcategories and sometimes the subcategories overlap to some extent. Certain pieces of motor
+ L+ R8 e# }( n$ S' b" m4 H1 Wcontrol equipment can accomplish multiple functions from each of the topics or categories.
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: ]0 e, R: X0 R% pThe four categories include:
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" C' R4 p: a8 E a4 y1) Starting the Motor ; X3 Z6 j; [ {; G
7 _) t! X5 y! h# v7 o; bDisconnecting Means
! N0 c' r, \' ?( q) aAcross the Line Starting ' x. \3 ]" r4 T
Reduced Voltage Starting
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2) Motor Protection
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& i7 |) `: M8 V8 S; }& K4 A8 N- dOvercurrent Protection ( o4 F# C7 c0 l2 V
Overload Protection . v2 _! P+ p6 F: g1 E1 S% z& T
Other Protection (voltage, phase, etc)
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* Q" W, I4 v) E; o3) Stopping the Motor / d, _0 b3 v" w! }8 {
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Coasting
3 L/ b, W/ H, o; }" E. o7 b6 xElectrical Braking 7 K5 c: J$ E7 b: ]5 p6 i% }
Mechanical Braking
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* c9 p Z. Q4 |& p: b+ F) h, H4) Motor Operational Control
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8 Z* V8 N* F ]' X5 e0 sSpeed Control
- E7 z4 U" \1 \1 n, yReversing
, h: g+ R9 V, J. j0 k7 pJogging
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