On delay switch

IBWET · 07 October 2009, 17:13

Can anyone point me in the right direction for a marine 'on delay timer' The cunning plan is to incorporate this along with a piezo in the bilge positive.

There are lots on the net that wouldn't last two minutes in the sea air etc.

The objective is to time how long the bilge pump takes to empty the well,set the timer to sound the piezo at this duration, so in effect the sound is the reason to switch it off,I won't have to look to see if there is still water present.

As an additional wee question, are the carling switches easy to remove from consol,(I don't want to break it to find out) as I want to fit one that illuminates.

jambo · 07 October 2009, 18:29

Ian would your float switch not switch it off for you?
Billy

jyasaki · 07 October 2009, 18:57

http://www.waterwitch.info/

There are others out there as well.

jky

IBWET · 07 October 2009, 18:59

Quote:

Originally Posted by jambo

Ian would your float switch not switch it off for you?
Billy

I think they are unreliable,it also means a break in the line back there ,so another oppertunity for corrosion,in addition to this the space in the well is limited after I fitted a fairly substantial transducer and the finally I decided against one as it means more screw holes...

The pumps feed is seperate to the breaker switch, so if inadvertently left on a float would keep running as the boat filled up with rain water,even on the trailer; flattening the battery. I would hear a piezo.

Thanks anyway..

IBWET · 07 October 2009, 19:10

Quote:

Originally Posted by jyasaki

http://www.waterwitch.info/

There are others out there as well.

jky

I had a look at those,but they seem to only do-

switch on then timer delay to switch off.

I'm looking for:

Switch on - then timer delay to 'on' - Piezo.

tinker · 07 October 2009, 20:00

Maplins sounds like the place for you to look see here for one such timer and there are a few others, just search for timers.

You could also house it in a waterproof enclosure, they stock them to.

IBWET · 08 October 2009, 07:05

Quote:

Originally Posted by tinker

Maplins sounds like the place for you to look see here for one such timer and there are a few others, just search for timers.

You could also house it in a waterproof enclosure, they stock them to.

I've looked at these,the problem I think I would have is if the power is cut because you disconnected the Main boat battery you would have to reset the timer which would mean digging it out of dash/waterproof box.

If I could fing one that had a rotary mech setting, or back up watch battery it wouldn't be an issue.

Thanks anyway.

9D280 · 08 October 2009, 07:59

If you are going to time how long it's been running, could you not put the switch in line with the + feed out the back of the switch to kill the motor after X seconds? If it's inside the console it should last a bit longer.

Alternatively replace your off / on switch with a pusbutton? I'm now getting to the perimiter of my knowledge here, but there are timer chips out there (555 series?) where the time is set by a resistor across two pins. That could be used to drive a solid state switch & be encapsulated. All you would need is a continuous + V in, and a "go" signal (e.g. from a non latching pushbutton). IF you hear the pump cavitating, push again for off. Wire the whole lot in parallel with your current switch so you have a manual override.

All you need now is an electronics expert to design the circuit!

IBWET · 09 October 2009, 16:44

Quote:

Originally Posted by 9D280

If you are going to time how long it's been running, could you not put the switch in line with the + feed out the back of the switch to kill the motor after X seconds? If it's inside the console it should last a bit longer.

Alternatively replace your off / on switch with a pusbutton? I'm now getting to the perimiter of my knowledge here, but there are timer chips out there (555 series?) where the time is set by a resistor across two pins. That could be used to drive a solid state switch & be encapsulated. All you would need is a continuous + V in, and a "go" signal (e.g. from a non latching pushbutton). IF you hear the pump cavitating, push again for off. Wire the whole lot in parallel with your current switch so you have a manual override.

All you need now is an electronics expert to design the circuit!

Cheers Ralph,

But I think i've sussed it-

http://www.amperite.com/documents/ST1D.pdf

keep an eye out for fires down the you know where....

jwalker · 09 October 2009, 20:47

Mr wet, the spec suggests a voltage drop of about 2.5v @ 3 amps. Will your pump be ok running on about 10v? Just a wee thought.

IBWET · 10 October 2009, 10:30

Quote:

Originally Posted by jwalker

Mr wet, the spec suggests a voltage drop of about 2.5v @ 3 amps. Will your pump be ok running on about 10v? Just a wee thought.

It's a rule 1100 gph manual ..So.....are you suggesting the pump will run slowly?..or not work at all. I'm no expert so your wee thoughts are gratefully recieved Mr W..

jwalker · 10 October 2009, 22:19

Dunno how it'll perform but I'd guess it'll be rather sluggish at 10volts. Might be good trying the pump before comitting. Ifn it's not satisfactory, you could use the timer circuit to energise a relay connected to the pump.

IBWET · 10 October 2009, 22:50

Quote:

Originally Posted by jwalker

Dunno how it'll perform but I'd guess it'll be rather sluggish at 10volts. Might be good trying the pump before comitting. Ifn it's not satisfactory, you could use the timer circuit to energise a relay connected to the pump.

That sounded great ,.. not wanting to impose but any chance of a wee drawing.
are you suggesting I run the pump at 10v? is there an easy way to alter something to supply this voltage, I've not bought the timer yet....

jwalker · 11 October 2009, 11:57

Can I go back to the beginning?...is the reason for your plan to remind you to switch the pump off cos you switch it on and forget it or is it to prevent you having to monitor the well to see whether it's empty? And, is the timer connected to the pump or just to the buzzer?

IBWET · 11 October 2009, 14:59

Quote:

Originally Posted by jwalker

Can I go back to the beginning?...is the reason for your plan to remind you to switch the pump off cos you switch it on and forget it or is it to prevent you having to monitor the well to see whether it's empty? And, is the timer connected to the pump or just to the buzzer?

Correct, on the first two points,the buzzer is to remind me it's on, the well only holds so much water, so based on a timed emptying of this well by the bilge pump, it would be time to switch the pump off.

Re the third point,my plan was to connect the timer to the piezo buzzer.

jwalker · 11 October 2009, 22:52

Okidoke, then I gave you a bum steer, sorry. The timer will only carry the buzzer current at 10volts. If you use a 9volt buzzer it'll likely be fine.

Searider · 13 October 2009, 20:12

Quote:

Originally Posted by IBWET

I had a look at those,but they seem to only do-

switch on then timer delay to switch off.

I'm looking for:

Switch on - then timer delay to 'on' - Piezo.

I've fitted these to both my ribs - 4 years and 5 years service respectively with no problems.

They switch on when they detect water and then switch off 20 seconds after they detect that the water has gone.

Great piece of kit.

geoffs · 17 October 2009, 19:25

R-S do a varietyof timer relays that will achieve what you want and have rotary setting knobs. I use them for on and off delays on systems.

9D280 · 19 October 2009, 15:49

Quote:

Originally Posted by IBWET

It's a rule 1100 gph manual

Quote:

Originally Posted by IBWET

the well only holds so much water,

1100GPH is just under 1.5L/Sec. To put that into perspective you could empty a 25L fuel tank in 15 seconds - I'm not sure I could do that by pouring it over the side of the boat! Unless you have a particularly large well, would it not be easier to just count to 15 or something? How long does it actually take to empty?

IBWET · 19 October 2009, 18:58

Quote:

Originally Posted by 9D280

1100GPH is just under 1.5L/Sec. To put that into perspective you could empty a 25L fuel tank in 15 seconds - I'm not sure I could do that by pouring it over the side of the boat! Unless you have a particularly large well, would it not be easier to just count to 15 or something? How long does it actually take to empty?

I would guess it (because I've not done it) takes about 30 secs to empty the well, just enough for you to get involved in something else while you wait....and I've got a memory like a chicken.

Re the 1100;don't believe everything it says on the tin...

I would say it's no more than a good healthy horse pi**