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why dc coils are bulky as compared to ac coils in a contactor? View All

7 years ago - 2 weeks left to answer. - 1 response - Report Abuse
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In a dc coil the current is only limited by the resistance of the wire. Usually the wire must be very long to have the right resistance. For an ac coil, the constantly changing current creates a changing magnetic field. This changing field induces current flow in the opposite direction, although not as large, as the initial flow, thus reducing the current. So a much shorter wire is needed for ac than dc. This changing magnetic field is also the reason transformers only work on ac and not dc.

7 years ago


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