Coombe Barton Posted May 31, 2010 Share Posted May 31, 2010 I've bought the PK-MAG electromagnets from MSE for Alex Jackson uncoupling. They're 4.5 ohms (2.7A at 12vDC). I've tried them with a car battery and they work OK, as I'd expect they would. Would this or similar tranformer work for them? http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_756417_langId_-1_categoryId_165650 Or is a car battery plus charger better? I'd prefer a transformer because of convenience reasons, and of course buying one already rectified with sufficient ourput power (33w required, 60w available, according to my calculations) is a bit of a struggle. Would the instant demand for power likely to be be too much for the transformer? Link to post Share on other sites More sharing options...
Brian Posted May 31, 2010 Share Posted May 31, 2010 I've bought the PK-MAG electromagnets from MSE for Alex Jackson uncoupling. They're 4.5 ohms (2.7A at 12vDC). I've tried them with a car battery and they work OK, as I'd expect they would. Would this or similar tranformer work for them? http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_756417_langId_-1_categoryId_165650 Or is a car battery plus charger better? I'd prefer a transformer because of convenience reasons, and of course buying one already rectified with sufficient ourput power (33w required, 60w available, according to my calculations) is a bit of a struggle. Would the instant demand for power likely to be be too much for the transformer? Hi I don't think a cool box will work! But ideal for the beers when operating the layout. :D Seriously though, the converter should be ok, but why not consider a regulated power supply? One like these supplied from Maplin is about the same cost and probably a better option IMO. Maplin Reg PSU Link to post Share on other sites More sharing options...
Coombe Barton Posted June 1, 2010 Author Share Posted June 1, 2010 Thanks Already have the coolbox transformer, which isn't used when I'm operating, so that'll be OK. And the beers I drink are served at cellar temperature. Link to post Share on other sites More sharing options...
RMweb Gold Donw Posted June 4, 2010 RMweb Gold Share Posted June 4, 2010 As long as its fully insulated so that the only connection between the primary and secondary is via magnetic flux ( testing with a multimeter for any connection btween the mains lead and the output terminal will do ) then I can't see any problem. If the unit is poorly regulated the voltage might drop a little but not really affect things. I am a little puzzled why you need such a high current. Are you planning to operate lots of eletromagnets at once? One last point is whether the unit might not like the spike produce on switching off so a capacitor to absorb the spike would be usefull like the condenser on a car ( old style ignition with points - are any still like that?) or a diode to block reverse voltage (100v PIV would be ok) although it would have to carry a large current. Donw Link to post Share on other sites More sharing options...
Coombe Barton Posted June 5, 2010 Author Share Posted June 5, 2010 Each coil if 4.5 ohms, so at 12v it's 3A max. Link to post Share on other sites More sharing options...
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