DC relay

RS part number 366-293 seems ok, 16A @ 125V dc, tho that might be for 2 poles, ie 8A @125VDC per pole, the data sheet implys this.

Generally if it will handle the current at a higher voltage then it will be ok at a lower voltage, inductive loads can cause a problem, needing a free wheeling diode to absorb the voltage spike and prevent contacts welding shut, which in an EStop situation is not what you want.

Is there any implication of you open circuiting your PSU at full load? might be as well to have a relay on the input side as well. You do have bleed resisitors on those caps dont you? otherwise you might get a nasty shock.... ;)

this advice is worth what you paid for it, but hopefully will help :)

There might be someone more knowledgeable along in a bit.

Dave

Hi Dave,

Many thanks for this - they seem just the job. There are some bleed resistors across the caps - the PSU itself was lifted lock, stock and barrel from the original electronics of the lathe. I'll look into putting a relay across the AC side of the PSU as well

Cheers

Alastair

this.www.rswww.comand do a search for it, or for power relay

Use a 2-pole or three-pole 10A relay with the contacts in series to give a greater breaking distance. We regularly use a 3-pole 10A 11-pin relay with all three sets in series on a small 110V 5A charger.

A 10 ohm resistor and something like a 1uf poly capacitor in series across the whole set of points will stop anything like an arc starting.

Don't forget an inverse diode across the relay coil to kill any spikes when turning the relay off.

Peter

-- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@easynet.co.uk