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DC Rated Contactors

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  • DC Rated Contactors

    I am doing some testing on a drive system that has a DC bus of 450 - 750V. The circuit will draw a maximum of 100A. I have found several DC contactors that are rated for 1000V and will handle the current but they don't have any auxiliary contacts and they are SPST. I need to have something that is DPST and allows auxiliary contacts. I thought I would check here since I have been using Automation Direct products for many years with good success. Does anyone have any ideas?

  • #2
    Considering what is involved in breaking a high(ish) voltage ,high(ish) current DC arc I'd think the selection is going to be very limited. Of course you can get double pole by wiring the coils of two single pole contactors in parallel, but I don't know about auxiliary contacts

    I first read that as double throw, and didn't think there was any chance of finding that with the specs you want be then I read it again.


    • #3
      Kilovac has some high current DPST relays/contactors. I have used them in the past, I'm not sure if you can get aux contacts or not as my applications did not need them.


      • #4
        Kilovac is a good choice for the circuit but I haven't found one with aux contacts. Many times three pole AC contactors will have a DC rating if you use two sets of contacts for a leg of the DC. Not really sure why that solves it but it is common with AC breakers also. I am going to keep searching. Thank you for your comments.


        • #5
          In the midst of a sleepless night, I found a data sheet on some kilovac SPST contactors that have aux contacts. I have to use two of them but now maybe I can sleep. Thanks again for your comments.


          • #6
            it is a bit late now but look at DC loop contractors. we use a lot of AB ans siemens. they are 3 pole the outside 2 pools are normally open and the center is normally closed. They are used on dc motors with the center contact normally used for a brake resistor.



            • #7
              Thanks z28z34man.