ENGINEERING.com has updated it's forum.  To post a question please visit the new Ask@ Forum.   

With a database of over 10000 questions the library will remain available for an extended period.
Q&A


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


13 years ago - 9 months left to answer. - 1 response - Report Abuse
Respond to question
    0      [lnkReport]        0       0       
Share |
  Responses

jwd217
 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.

13 years ago

Source:


  1     0         

ENGINEERING.com does not provide engineering advice. The Ask@ service is a forum for members to exchange ideas relating to the world of engineering. We caution users not to accept any responses that they receive without further validation, and not to rely on any engineering advice that they may get from other members of the Ask@ forum. ENGINEERING.com specifically disclaims any obligation to validate or verify any information posted within the Ask@ service. ENGINEERING.com encourages users to seek the services of a professional engineer for any engineering advice they may require.