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ELECTRIC MOTOR CONTROLS 6 i4 O, C( u: q! Z3 Q6 G& _
' o, u9 E2 m) ROnce the proper motor is selected, understanding the many various control devices available and ' @3 m- J( ]/ r( @. g
their uses and limitations becomes an important part related to reliable operation and protection of ) K% d( L# t; A3 S/ I* I+ Y; m
the motor and the personnel using the motor. l+ O3 D7 n3 U. f" k
9 E& ` \* w$ U3 zMotor Control Topics % W5 Q- K9 w; u ^
+ s1 H( s% v& i9 b! {% Q3 N9 lThere are four major motor control topics or categories to consider. Each of these has several
$ i! D, Q$ d. h# R' ^subcategories and sometimes the subcategories overlap to some extent. Certain pieces of motor
1 R( M1 }+ I1 Q- Y/ |& q; Kcontrol equipment can accomplish multiple functions from each of the topics or categories. 0 O( {( p! i0 V; E, v6 K3 B
6 }! E- H% p! L3 Z' JThe four categories include:
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1) Starting the Motor
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Disconnecting Means : z8 U7 i* f8 q! A9 C4 `( H' n( M* D
Across the Line Starting 0 f5 p! G7 s0 l5 E# B
Reduced Voltage Starting ( z0 O3 b' a3 _ I+ W+ t
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3 U& W2 |) J2 w- l$ u! a2) Motor Protection : O2 M' w6 _# J9 m" R
$ N! r6 J6 J+ x# y, ]Overcurrent Protection # ^6 C# T' Z6 Z
Overload Protection
' X, H8 i! ?8 D- |Other Protection (voltage, phase, etc) 8 J9 R2 Q3 T: T, l
Environment
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3) Stopping the Motor
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Coasting # O& O4 c) o0 q
Electrical Braking 9 J3 A# J+ T7 ^
Mechanical Braking # X8 y: D v' x" @' H6 v9 q, J
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4) Motor Operational Control
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+ H, G8 |& D- ?& S$ ~0 ySpeed Control " C3 l8 \5 S: V
Reversing
, H4 q( T I- mJogging D$ y- |0 h+ G1 P" `
Sequence Control |
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