Switching On/off 240v Via 26vdc - Electronic Circuits Projects Diagrams Free

nickk1 · 14th January 2008, 11:36 AM

Hi
First post my electronic no how is close to zero so can any one help.
I have a 240v feed which I need to switch via max 26vdc is there a way I can do this amps would be 20 A max?
Nick

**Nigel Goodwin** · 14th January 2008, 12:59 PM

A simple relay?.

nickk1 · 14th January 2008, 01:08 PM

how would I wire it and what one, size make would I be looking for.
As I said no how limited.
Nick

**Nigel Goodwin** · 14th January 2008, 02:07 PM

You need to tell us exactly what you're switchig, and exactly what the control signal is.

Cry_Wolf · 14th January 2008, 02:25 PM

If you use a SPDT (Single Port Double Throw) It would have five connecting points, VDC , GND , NO , NC and C. When you apply voltage across VDC and GND , NO and C points become short otherwise NC and C are short.

So if you connect your connect your device through C and NO, It will work when you apply VDC to your relay.

And remember, to be on the safe end connect an appropriate diode across VDC and GND to avoid Back EMF

nickk1 · 14th January 2008, 02:39 PM

What this is for is turning on and off a gas solanoid valve in a welder the valve is rated at 240v 50hz.Power going to the valve is 240v ac, I want to controle it i.e turn it on / trurn it off via the controle trigger in the tourch which gives out 26vdc this supply comes from a transformer. Sorry dont know what you mean by controle signal.
Nick

**Nigel Goodwin** · 14th January 2008, 03:40 PM

The 26V is the control signal, you mention it's DC, do you know what current it can provide?.

Presumably the 240V valve doesn't require a lot of current?, so you just need a 24V relay (24V is a standard voltage), and wire it as above.

nickk1 · 14th January 2008, 04:05 PM

Please forgive my stupidity but do I use a 24v dc relay or a 240v ac one?
Nick

**Nigel Goodwin** · 14th January 2008, 05:05 PM

The relay 'coil' is 24V DC, the switching contacts are rated for 240V AC.

A relay is essentially a mechanical switch (the contacts) moved by an electromagnet (the coil).

nickk1 · 14th January 2008, 05:07 PM

What size diode would i use to stop EMF?
NICK

**Nigel Goodwin** · 14th January 2008, 05:13 PM

Quote:

Originally Posted by nickk1

What size diode would i use to stop EMF?
NICK

What makes you think you need one? - and a diode doesn't do that.

Like I asked before, what actually feeds this 26V?, and what is is supposed to feed?.

nickk1 · 15th January 2008, 10:24 AM

Ciruit working thanks for all your help
Nick

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14th January 2008, 11:36 AM	(permalink)
nickk1	Switching On/off 240v Via 26vdc Hi First post my electronic no how is close to zero so can any one help. I have a 240v feed which I need to switch via max 26vdc is there a way I can do this amps would be 20 A max? Nick

14th January 2008, 12:59 PM	(permalink)
Nigel Goodwin	A simple relay?. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

14th January 2008, 01:08 PM	(permalink)
nickk1	how would I wire it and what one, size make would I be looking for. As I said no how limited. Nick

14th January 2008, 02:07 PM	(permalink)
Nigel Goodwin	You need to tell us exactly what you're switchig, and exactly what the control signal is. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

14th January 2008, 02:25 PM	(permalink)
Cry_Wolf	If you use a SPDT (Single Port Double Throw) It would have five connecting points, VDC , GND , NO , NC and C. When you apply voltage across VDC and GND , NO and C points become short otherwise NC and C are short. So if you connect your connect your device through C and NO, It will work when you apply VDC to your relay. And remember, to be on the safe end connect an appropriate diode across VDC and GND to avoid Back EMF __________________ Khizer Naeem Mughal IIUI

14th January 2008, 02:39 PM	(permalink)
nickk1	What this is for is turning on and off a gas solanoid valve in a welder the valve is rated at 240v 50hz.Power going to the valve is 240v ac, I want to controle it i.e turn it on / trurn it off via the controle trigger in the tourch which gives out 26vdc this supply comes from a transformer. Sorry dont know what you mean by controle signal. Nick Last edited by nickk1; 14th January 2008 at 03:25 PM.

14th January 2008, 03:40 PM	(permalink)
Nigel Goodwin	The 26V is the control signal, you mention it's DC, do you know what current it can provide?. Presumably the 240V valve doesn't require a lot of current?, so you just need a 24V relay (24V is a standard voltage), and wire it as above. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

14th January 2008, 04:05 PM	(permalink)
nickk1	Please forgive my stupidity but do I use a 24v dc relay or a 240v ac one? Nick

14th January 2008, 05:05 PM	(permalink)
Nigel Goodwin	The relay 'coil' is 24V DC, the switching contacts are rated for 240V AC. A relay is essentially a mechanical switch (the contacts) moved by an electromagnet (the coil). __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

14th January 2008, 05:07 PM	(permalink)
nickk1	What size diode would i use to stop EMF? NICK

15th January 2008, 10:24 AM	(permalink)
nickk1	Ciruit working thanks for all your help Nick