Parallel or series question

Discussion in 'General Electronics Chat' started by Man_in_UK, Feb 6, 2009.

  1. Man_in_UK

    Thread Starter AAC Fanatic!

    May 13, 2008
    I work on a bit of kit now and again that comes from the USA, for now we shall say that they power ac motor via contactors/relays.

    When I get them the contactors (that have 2 sets of norm open contacts) are always wired in series ....... I always change it to parallel to spread the load across the contacts.

    Is this a good idea or bad ?
    Is there any advantage to powering a motor through 2 seperate contacts in series ?
  2. KL7AJ

    AAC Fanatic!

    Nov 4, 2008

    I think the series relays are for the purpose of "step starting". Usually the first set of contacts applies a resistance to reduce the starting current, then the "final" relay kicks in, bypassing the first one.

  3. Man_in_UK

    Thread Starter AAC Fanatic!

    May 13, 2008
    I cannot comment on this technique as I have no experiance on it but the contactors I am dealing with have no clever delay or resistance, just 2 "no" & 2 "nc" (the "nc" get used in the brake circuit).

    Both the "no" contacts are driven by the same solenoid so they close as a pair.
  4. dsphanibabu

    New Member

    Feb 13, 2009
    hi can u send me the links for otc cranes?
    i need 2 make documentation on it....
    so plz send me the details..........