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ELECTRIC MOTOR CONTROLS $ s" u/ H. ?9 T. w, u! g+ A
. ^# G! U: R$ O6 P8 s3 I* P6 J+ Q# cOnce the proper motor is selected, understanding the many various control devices available and 3 Y3 B. M! S3 w2 {& l9 k
their uses and limitations becomes an important part related to reliable operation and protection of ! C, l3 D6 ~ N3 U
the motor and the personnel using the motor.
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/ H7 J9 l; n; H1 D7 ~4 aMotor Control Topics
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7 G/ C- ]* o" S" Z; j, H; l) U: K; WThere are four major motor control topics or categories to consider. Each of these has several - `9 T/ O4 E$ }4 }8 H
subcategories and sometimes the subcategories overlap to some extent. Certain pieces of motor % l1 W9 A' x5 t6 R: [
control equipment can accomplish multiple functions from each of the topics or categories.
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) B3 e. |, l; ?; ZThe four categories include: 0 B5 p1 l$ N' v2 m
5 s7 E+ L% W) Z! u/ z9 t1) Starting the Motor ( n( [" ^/ C0 }& X+ r9 p
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Disconnecting Means : I7 {* w, ~' I4 O
Across the Line Starting
7 E6 x+ B: |& h6 }( S* J2 VReduced Voltage Starting 7 f+ y+ z3 Z) ^ w; M$ P' e( x- J2 T
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2) Motor Protection
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) F# W+ t4 q* lOvercurrent Protection - {5 W4 u4 c4 d. @) Z3 T) a) ]
Overload Protection ( t: `7 f, S' _* @
Other Protection (voltage, phase, etc)
- \& j! w F+ }; u2 cEnvironment
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3) Stopping the Motor
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% g5 `% _8 x, E7 }% O* p- kCoasting
+ V" ?5 F% M# b! @" e& uElectrical Braking
0 O2 f# {$ Y/ q; d5 V% q( yMechanical Braking $ O9 c0 Y' s& ^
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4) Motor Operational Control ( E+ M; j1 C5 H: a$ r3 ]
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Speed Control 2 W7 D ~; w+ H& m% K$ y! A& Q- }
Reversing 1 m( p) A$ u0 w/ s8 }' F
Jogging
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