9
Fig. 11 Direct input coil type Fig. 12 Double coil type
(1) Direct input coil type
Because of the temperature rise of the coil, DC electromagnet is larger than AC one, thus DC operated contactor
is higher than AC operated one.
(Operation)
When the coil is excited, the moving core is attracted to the fixed core, and the moving contact linked to the moving
core comes into contact with the fixed contact, then closes the circuit. When the coil is released from excited condi-
tion, the moving core separates from the fixed core and the moving contact parts from the fixed contact, then opens
the circuit.
(2) Double coil type
The dimension of double coil type DC operated contactor is the same as that of AC operated one. The double coil
is a coil which has 2 coils, closing coil and holding coil wound on the coil bobbin.
(Operation)
When a voltage is applied to the coil, a current flows only to the closing coil, the moving core is attracted to the fixed
core, and the moving contact linked to the moving core comes into contact with the fixed contact, then closes the
circuit. A current flows to both the closing coil and the holding coil just before the moving core comes into contact
with the fixed core; the current is reduced by a large resistance of the holding coil, and as a result, the temperature
rise of the coil is controlled. The operating circuit is as shown in Fig. 13.
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