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ELECTRIC MOTOR CONTROLS
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Once the proper motor is selected, understanding the many various control devices available and
3 ~8 _- u4 z, z. r- k, {their uses and limitations becomes an important part related to reliable operation and protection of . W' D7 e( o" b# T4 C! }
the motor and the personnel using the motor.
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Motor Control Topics
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$ I3 q6 \6 o2 i6 @# F* m( sThere are four major motor control topics or categories to consider. Each of these has several
2 `4 p: f( Q' n. {% n& Tsubcategories and sometimes the subcategories overlap to some extent. Certain pieces of motor
/ m& k8 @0 v+ _- L' mcontrol equipment can accomplish multiple functions from each of the topics or categories. ( R4 `4 j+ l* h9 C/ H! T) e6 o
# w. c: }0 L# K* A% O( T( b& Q+ YThe four categories include: & x9 ~9 k- M9 V! A6 ]% {9 Z
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1) Starting the Motor
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Disconnecting Means ) H( Y. U' t$ l4 h; ^: H# y
Across the Line Starting
6 `9 a& C+ A& W7 Y! X: h2 J' DReduced Voltage Starting
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7 ?. l. p( p9 F2) Motor Protection 5 W& G" C. [; [5 O: Q
) e6 w u2 E* M, AOvercurrent Protection . X6 L. Z1 E/ ^2 C8 o! n" Q# Q/ q
Overload Protection
$ C5 k3 B( `* y2 U) O5 I3 cOther Protection (voltage, phase, etc) m8 i6 \# P( u. |- H$ c
Environment
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3) Stopping the Motor
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; u; n0 w9 T- h! PCoasting
& K0 S* d( E4 X. P# i6 J& Y6 k9 FElectrical Braking
3 Y) P( G3 }; Y0 b- gMechanical Braking
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# o$ k N+ q- F5 f1 T8 I4) Motor Operational Control
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Speed Control " ], K/ N! `1 y; d
Reversing
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