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Can someone please help! - 12v timer switches

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Ste663

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I have a 12v electric ball valve (3 wire) and a 12v 2 wire inflation pump which I am using for a project. I need the ball valve to open then close after 10 seconds and the inflation pump to run for 12 seconds simultaneously. I have managed to achieve this using 2x12v timer switches which I purchased off ebay (link below) . The problem is I need a second button/switch to press that will deflate by opening the ball valve then close it 20 seconds after, I thought this would be achievable by introducing a third timer switch and a simple on/off/on switch, I wired the first two timer switches to the first 'on' then the single timer switch to the second switch but they all seem to interfere with each other and when I want to power the single one they all light up.

**broken link removed**

Hope someone can please help as I haven't got a clue when it comes to electrics or anything for that matter.

Regards

Ste663
 
Please post a wiring diagram as it is wired now. You can draw it with pencil, and post a close-up photo of the diagram...

? about the ball valve. Does it have two ports or three. If only two, where does it exhaust to? Is it that it exhausts backwards into the inflation pump which isn't running at the time?

I dont understand the "three wire" aspect of your ball valve? I have some here that only have two wires. They require reversing the DC polarity to run the motor CW and CCW to open and close the valve, respectively.
 
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Hi, thanks for your response. Any advice would be greatly appreciated.
 

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The ball valve has two ports and it is positioned before the pump, so when inflating the air passes through the valve and then the pump.

The valve has three wires (one being a ground/earth) so it can be reversed by switching the poles.

Hope the above makes sense?
 
Try adding 4 diodes of suitable current rating. One between timer 2 NO contact and the valve. One between timer 2 NC contact and the valve. One between timer 3 NO contact and the valve. One between timer 3 NC contact and the valve. The cathodes to the valve and the anodes to the timers.

Edit I think just the two diodes from the NC contacts would solve the problem.
 
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...The valve has three wires (one being a ground/earth) so it can be reversed by switching the poles...

Very important:

Take an Ohmmeter and measure the resistance pair-wise between the ball valve wires (three separate measurements). Post the results.
 
Thanks guys. I will definitely do both..I know absolutely nothing about electrics so I'm baffled with which diodes I need. My power source (at the moment) is a 12v 6amp, so do I need a diode compatible with that or the pump and valve?
 
This is why I believe you need the diodes. When the switch is in the position using timer 1 & 2 and timer 2 is in the state with common (+12V) routed to the NO contact this will put +12 volts on the NC contact of timer 3 as it is connected to the same point. As timer 3 is not powered its NC contact will be routed to its common connection which is connected back to its + 12 volt input. As a result timer 3 will start. The same sort of thing will happen when the switch is in timer 3 position. Putting diodes between the NC timer outputs and the valve should prevent this back feed happening. The diodes only need to be rated for the current taken by the valve. (The cathode of the diodes is the end marked with a band.)
 
This is why I believe you need the diodes. ..

All of the stuff about the diodes is dependent on how the valve works. Please supply the Ohmmeter readings before worrying about diodes.
 
Thanks for all your advice. I don't actually have ohmmeter but I will order one. On the valve it's says 4w and 1mpa. Is the 1mpa the figure I need? I will still measure it once my ohmmeter arrives.

Thanks again
 
4w (4 Watts) is the power rating of the valve so as it is a 12 volt valve the current will be 4/12 = 0.333 amp (= 333 mA) 1mpa ( 1 megapascal) is the pressure rating of the valve. (1 megapascal = 145 PSI) The reason MikeMi has asked you to measure the resistance of the valve is to try to understand the design of the valve. It could be driven by a motor or it could use solenoids. If you could post some information on the valve it would be a great help. For example manufactures data sheet, manufacturer name and part number, some pictures of the valve from different angles with something in the picture to give a sense of scale. As the current is less than 1 amp any of the 1N400x (The "x" will be a digit from 1 to 7 indicating the voltage rating of the diode. ) range of diodes would be OK. Buying 4 1N4001 diodes would probably cost less than a multimeter but if you plan to play round with electrical or electronic devices a multimeter is an essential tool. If you live near CPC in Preston (UK) you can get 10 1n4001 diodes for £0.36 They are £0.49 each at Maplins but there are branches of Maplins in most (UK) towns.
 
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I can't thank you enough Les. I have been scratching my head for days over this. I have ordered some diodes off ebay which will arrive on Tuesday. This is the valve I'm using - **broken link removed** . I don't have the instructions for it but I have just requested them.

Thanks again.

Ps it's definitely motorised.
 
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There is enough information on the ebay advert. I think the diodes will solve the problem.
 
...This is the valve I'm using - **broken link removed** . I don't have the instructions for it but I have just requested them.

Thanks again.

Ps it's definitely motorised.

The link says "seller has removed this item"

Does your valve match this picture?


valv.gif


The way you have wired it, the valve and the deflate timer must remain powered for ever (the sequence is not self-completing; you have to turn the thing off by centering the toggle switch). Is this ok? Is the long-term power drain a problem?
 
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Timer_01.jpg Here is another possible solution. It only uses the switch for switching the +12 volts. The negative is connected to the timers, valve and pump all of the time. The switch now switches the power to the timers with one pole and the common of the timer output relays with the other pole. By doing it this way the unused timers so not have a path from relay common to the timer power input.
 
Mike- yeah that's the valve configuration. As far as the power goes I'd ideally like to have to work how you suggested, is that possible? It would be perfect to just have a inflate and deflate button/toggle/switch.
 
Thanks Les, just to complicate things, would it be possible to reverse the pump using a 4th timer switch? I could then draw the air out when the valve is open.
 
Ste663,
I have assumed that as the valve only has two ports that that in the deflate position the air passes through the pump (In the reverse direction.) to escape. If this is the case I think it must be a centrifugal pump. Reversing the rotation of a centrifugal pump does not reverse the flow. (It even works to some extent with the motor running in reverse.) If it is some type of positive displacement pump then reversing it would need a relay. You would need to give some details of the pump. I do not see why you would need an extra timer. Did you try the alternative solution I suggested in message 16 ?
 
Thanks Les, I have literally just walked in from a long weekend away with the family so I've tried nothing yet. Diodes should be here in the morning so I'll get cracking in the morning.
 
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