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Normally open or closed?

Discussion in 'Electrics UK' started by Mike2007, 16 Oct 2021.

  1. Mike2007

    Mike2007

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    Just purchased this contactor and it seems like a N-O contactor?
    It is open circuit across all terminals.
    What do you think?
    20211016_145725.jpg 20211016_145757.jpg
     
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  3. flameport

    flameport

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    It is. As indicated by the diagram on the front. 2 poles.
     
  4. Mike2007

    Mike2007

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    It was sold as N C contactor to me via ecommerce. Was going to return it as wrong sort until I tested it.
     
  5. bernardgreen

    bernardgreen

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    It will be open circuit across any combination of terminals with the exception of A1 to A2 ( the ends of the coil )
    Only when there is 230 volts AC applied to A1 and A2 will

    Terminal 1 be connected to terminal 2
    Terminal 3 be connected to terminal 4

    Eaton MEM CR2020230A 20A MOD Contactor 2NO 230VAC
    https://www.electrical2go.co.uk › memshield-3-20a-2n...
    Eaton MEM CR2020230A 20A MOD Contactor 2NO 230VAC
    CR2020230A ... A 2 Normally Open 20 Amp 230v AC Contactor, sized to a standard 18mm module width
     
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  7. mattylad

    mattylad

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  8. Mike2007

    Mike2007

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    What ohms should I expect from the coil?
     
  9. bernardgreen

    bernardgreen

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    The resistance of the coil when measured with DC test equipment will be very low compared to the operating impedance when a 50 Hz mains voltage is applied to the coil. I cannot find any information about DC coil resistance values for AC coils
     
  10. BS3036

    BS3036

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    I think you should expect whatever it turns out to measure. The chances of a new one being broken are extremely low.
     
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