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  1. #11
    Neale's Avatar
    Lives in Plymouth, United Kingdom. Last Activity: 18 Hours Ago Has been a member for 5-6 years. Has a total post count of 1,156. Received thanks 209 times, giving thanks to others 5 times.
    You have to dig deep in the catalogue to find the numbers, but it looks as if the 24V DC version takes around 150mA. The low-power version is about half that.

  2. #12
    Quote Originally Posted by Neale View Post
    You have to dig deep in the catalogue to find the numbers, but it looks as if the 24V DC version takes around 150mA. The low-power version is about half that.
    So the question now is...can m_c spare the 150
    .Me

  3. #13
    Quote Originally Posted by Neale View Post
    Here's a question for the gang, though. Like a lot of small contactors, this is designed to handle 3-phase and therefore has 3 main N/O contacts. If you are using it on single phase, would you just use one contact, wire all three in parallel, or all three in series?
    If I understand the question I connected live and neutral (brown and blue) to the contactor so they were both switched. See second photo in post #102. Earth was permanently connected elsewhere. I controlled the switching using 24V DC logic (white wires) from the estop circuit
    http://www.mycncuk.com/threads/6988-...cnc_MK3/page11
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  4. #14
    Neale's Avatar
    Lives in Plymouth, United Kingdom. Last Activity: 18 Hours Ago Has been a member for 5-6 years. Has a total post count of 1,156. Received thanks 209 times, giving thanks to others 5 times.
    That's a good answer to a slightly different question! No problem at all with that, if you want to switch neutral as well as live. Perfectly reasonable thing to do. What I was thinking about more, though, was the case where you are just switching live (which is what I do, and leave neutral connected). In this case, you might think of putting the contacts in parallel, to reduce the current through each contact by sharing it across all of them. However, when you switch off (probably worst case for arcing at contacts), inevitably the contacts will open at slightly different times so you will end up with one contact set, the last to open, switching the full current. I have seen suggestions that it is better to wire the contacts in series, which can reduce arcing. Some heavy-duty switchgear works like this, especially if switching DC. Anyway, it's all a bit academic if you are working within the spec of the contactor (or relay), I would hope.

  5. #15
    If you use just one contact you can use the other two for switching something else.
    ..Clive
    The more you know, The better you know, How little you know

  6. #16
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 15 Hours Ago Has been a member for 9-10 years. Has a total post count of 2,121. Received thanks 233 times, giving thanks to others 5 times.
    Quote Originally Posted by Lee Roberts View Post
    So the question now is...can m_c spare the 150
    Should be fine. I've got 2.1A of 24VDC, which sole purpose in life now the old controller is gone, is to power a few relays and sensors. If need be, I can upgrade it or fit a second supply.
    .
    I've ordered a suitable ABB contactor that only takes 3.5W coil power from RS, as I get free next day delivery. I even ordered one with a NC Aux contact, which I can use to switch in a drain resistor for the capacitor, rather than have the resistor continually warming things up.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  7. #17
    Hi

    I have had a dig around the WEG site and I saw consumption figures for the CWC16 coil. The C03 coil takes 2.6 to 3.7 Watts and the L03 coil takes 1.7 to 2.7W. 2.7W at 24v is 113 mA, so it shouldnt tax the power supply a great deal.

    I have just measured an ABB contactor with a 24v AC coil which gives 5.5ohm - that would be taking about 100w on 24vdc, I don't know what the impedance to 50Hz AC is, but it still seems a hefty whack.

    The WEG wee beastie is pricey though in the WEG catalogue - so £12 from Chalon seems a damn good price, especially if you get the L03 coil.

    Cheers,

    Rob
    Albert Einstein may have been a genius, but his brother Frank, was a monster

    Having just moved to Windows 10 (which is crap) My stress levels are through the roof !!!

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  9. #18
    Quote Originally Posted by m_c View Post
    Should be fine. I've got 2.1A of 24VDC, which sole purpose in life now the old controller is gone, is to power a few relays and sensors. If need be, I can upgrade it or fit a second supply.
    .
    I've ordered a suitable ABB contactor that only takes 3.5W coil power from RS, as I get free next day delivery. I even ordered one with a NC Aux contact, which I can use to switch in a drain resistor for the capacitor, rather than have the resistor continually warming things up.
    Good stuff, I like the drain resistor idea its also something I thought about doing for the caps on my driver PSU, dont forget the pics once installed ;-).
    .Me

  10. #19
    I use the softstart, via 240v switch, than contactor via fail safe latching, but after reading few post will try MCB type D without softstart - will upload results.

    Meantime here is my softstart

    Click image for larger version. 

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    It switch primary coil via 4x10W resistors just to kill in rush current and after second small relay bypassing resistors before they became too hot. This delay is enough for peak to go down.
    This is only inconvenience for toroid trafo I know.
    Click image for larger version. 

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