magnetic contactor.ppt
TRANSCRIPT
Motor Controls
Prepared by Sir. Rene A. Sy Amg Skilled Hands Technological Col.
Magdalena Campus.
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Magnetic Contactor
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Magnetic Contactor used to control the operation of an electric current a large relay usually, used to switch current to an electric current motor or other high power load
a device uses small control current to energize or de-energize a load. It can handle high amounts of current and also combined w overload relays to create motor starters
electrically controlled switch used for switching a power circuit, similar to relay except with higher amperage ratings.
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Motor controls containsControl Circuit
A circuit contains the control device that will initiate starting or stopping the motor, by the means of the start/stop push button.
Control circuit provides a temporary path for energizing he coil and permanent path through the contact
Delays energization of the coil preselected time to allow switch contact bounce to cease.
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Prevents a reestablishment of the temporary path for preselected time after the contact close
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Power circuit
Power circuit carries the motor load current
supplies the line side of main terminal of the contactor
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Control circuit composed of
1.Overload relay or over load
2.Magnetic contactor/Main terminal
3.Transformer
4.Start stop station
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Symbols
Start switch is normally Close, while the stop is normally close
Magnetic contactor coil or holding coil
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Overload block with heater
3 main contact for 3 phase
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OL
Normally closed overload switch
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Fuse
Circuit breaker
MotorMotor
T1
T2
T33 phase motor
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Contactor markings and label
1
2
3
4
5
6
(European)
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L 1 L2 L3
T1 T2 T3
(R) (S) (T)
(U) (V) (W)
(American)
A1 and A2- for holding coil
95
9698
OL
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Control Circuit Diagram
L1
1 2 3 4
(Self holding)
A1h c
13 14
OL
L2
A295
96
(N.C)(N.O)
StopStart
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Example of Wiring Diagram
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