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.
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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 [emoji12]Quote:
Originally Posted by Neale
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 circuitQuote:
Originally Posted by Neale
http://www.mycncuk.com/threads/6988-...cnc_MK3/page11
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.
If you use just one contact you can use the other two for switching something else.
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.Quote:
Originally Posted by Lee Roberts
.
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.
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
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 ;-).Quote:
Originally Posted by m_c
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
Attachment 20210
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.
Attachment 20211