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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
( X- G6 U; W/ T1 y+ y ttheir uses and limitations becomes an important part related to reliable operation and protection of 9 X" \% S+ g0 R7 F/ [0 ?' D/ z5 c- R
the motor and the personnel using the motor. ) p2 m" t" f1 ` S+ @& E
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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 v' h1 y8 Z. \- m4 N+ Esubcategories and sometimes the subcategories overlap to some extent. Certain pieces of motor 3 q' R( ]5 J6 E. c
control equipment can accomplish multiple functions from each of the topics or categories.
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6 B. a" O) J$ `' p |% h9 RThe four categories include:
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1) Starting the Motor
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2 a# c/ K8 E) |4 A5 X) ZDisconnecting Means
2 i; _/ _" \- `- `- f" S9 }Across the Line Starting
u* e }) j; e" k4 t3 YReduced Voltage Starting : @4 H& d" R7 H
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2) Motor Protection + W3 |% N, t y4 ^' W6 a( E
! ?3 m9 R! Z: N: ?% S7 x; g( U! z- uOvercurrent Protection / ]& T5 \' _8 G; c0 e7 p/ N E" W4 e
Overload Protection 4 K0 g1 c1 _' |- F' j) F0 f
Other Protection (voltage, phase, etc)
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3) Stopping the Motor
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; | d [) _& \& ~) v$ H, kCoasting 2 B' F# g9 e- i/ ?1 j! J
Electrical Braking $ C* d8 w* p7 k% o( r+ G0 Z" Q
Mechanical Braking 8 a8 G4 w2 @& j& a" p
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4) Motor Operational Control 6 _, x/ `" ^4 U
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Speed Control
1 u0 r* ]) @( W E" ]+ v: a" aReversing
5 f- H3 k0 f. ?Jogging
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