dely shut off relay

I am looking for a relay that will continue to carry power for about five minutes after switch is turned "off". McMaster Carr has some but they are a bit pricey. Would like to keep it simple.

Putting together a plan for venting the engine compartment and would like for the fans to stay on for several minutes after the ignition is turned off.

If anyone has experience with such a relay perhaps you could steer me in the right direction

Chuck try this
Timers | Redarc Electronics
I have used them in many applications they work fine and can be adjusted over a wide time range.

Darrell DRB #46
LS1 G50

Chuck,
Not quite the same, but go and have a look at a shower fan. The one I have has a time delay built in and has 3 connections (permanent Power, switched power, earth). It can time for the shower fan to stay on for up to 20 mins. You could just get one of those and convert.

Or you could build out using resistors and capacitors, one of these maybe: http://www.maplin.co.uk/media/pdfs/qh66.pdf

Mike Trustie has this feature on his car. You'll need to contact him to determine what he used.

Chuck,
There are two products out there specifically for the override function. They allow the fan and the water pump(if you have one) to run on after shutdown.
The first is a Davies Craig unit, the EWP Digital Controller, part no. 8020. It is designed for their electric water pump and their booster pump, but can be modified to run the fan as well. It will control other fans but they have to have an amperage usage under 30. In the overrun mode it will run for 2 minutes after ignition shut down or until the temp has been reduced 5 degrees C below the set point. Its main function is it turns the fan/waterpump on gradually(pulsing at 6V:10 sec. on 30 sec off, ramping to 6V: 10 sec on 10 sec off til the third setting is reached where it ramps up to full power).
The other unit is the SPAL fan controller(they have instructions for controlling the water pump as well). Their manual override is controlled with a switch that has to be activated for the override function. This allows the fan and pump to run on after ignition cut off for basically the same amount of time. I believe it is called their PMV3. They advise not to use just the fan for this option because it will run almost all the time. The reason is, it is tied to the thermostat which is in the block(most engines) and will never show a drop in temp if the water pump is not running. Running just the fan would lead to running the battery down. Their instructions are a little vague on the overide. The wording was changed from the older units likew the one I have but it does the same thing. Both come with the controller, harness and instructions and can be mounted in the drivers compartment for visual monitoring if you wish(blinking color lites or in the engine bay as they are both sealed against the weather.
I am going to use one or the other(I have both) and I plan to add two fans to blow air along the bottom side of the top of the rear clip. They will be tied to a simple thermostat that will cycle them as needed independently to keep the top of the rear clip cool. My exhaust doesn't come as close as yours does, but I may add the insulation as you have just in case. The fans will be mounted on the roll cage portion of the rear clip, or the mounting hardware(Aerocatch). You can go to their web sies and look at their instructions. They aren't difficult to follow.
If you are interested in one of my units let me know. I will be deciding on which I plan to use soon and would be willing to part with the other.

Bill

Thanks Bill...another one of my questions answered without even posting the query!

CESLAW said:

I am looking for a relay that will continue to carry power for about five minutes after switch is turned "off". McMaster Carr has some but they are a bit pricey.

Click to expand...

Ouch, yes. $45 for an ugly-ass '50-s looking octal tube socket relay.

The Australian ones mentioned earlier are lovely but cost $150.

I don't have a part number for you (yet) but a rear window defroster relay should work. They typically stay on for 5-15 minutes and then shut off, and should be cheap (~$10) at your local parts place.

Another option for a delay off timer is, Dear i say it is a Turbo timer.

They are normally adjustable to several minutes.

A couple of relays on the output and you could drive both pump and fans.

Thanks for the good ideas.

Here is another.

Delay Timer, ELK-960. This little gem is less than $30 and can be programmed to shut off from one second to sixty minutes after trigger power source is turned off.

http://www.hometech.com/hts/products/automation/timers/standalone/index.html#AL-960


Can any one think of a reason why this would not work???

I have a time off relay on my electric water pump, it runs for two minutes to take the heat soak out of the engine, if the water temp is above 185 degrees it also allows my fans on the radiator to come on to remove the heat. I have run the system for a couple years now without a hick up. Mike Trusty recommended this to me almost 20 years ago along with the bypass thermostat which in my opinion is a must do in our cars has keep my car running cool and never has over heated in the worst of conditions. Here is the latest Solid State relay that is under $50 bucks that he recommends.


Timer Relays Relays Relays And Solenoids* - Waytek Wire

Just to throw two more cents into this, when I was a relay technician for a local utility, we used agastats for delayed tripping. They were adjustable, and when I just now looked to see if any were offered on Ebay, it appeared there were quite a few at very reasonable prices.

Chuck

It seems like you have been given many options. Another one I thought of is the control/switch setup from the earlier water-cooled motorcycles (they started appearing in the mid 80s, at least as far as the Japanese bikes). I'm pretty sure the early setups were strictly temperature-based timers (not computer controlled). I bet you could pick one up for just a few bucks at a junkyard or on ebay, although I have not looked for one.

Seems to me Kawasaki had a 900cc bike styled to look a bit like a drag bike that was water cooled and had a temperature-based, timed fan. For some reason, this bike kept popping into my head as I was reading this thread.

Eric

I cannot imagine building a GT without the internet and this forum. Thanks for all the good suggestions. I have ordered the Waytek 10 minute off delay timer per Jack Houpe's suggestion. It looks perfectly suited to what I am doing.

What is surprising is that Waytek did not pop up on any of my google searches.

Chuck it was a stroke of luck, Mike Trusty emailed that info to me a couple days before you posted this thread. Glad it worked out for you.

I have just finished the wiring of the Off Timer Relay from Waytek. It was a little confusing to me, but Chuck got me started and I now understand it. Here is the data page from Waytek.



I chose the 75543 relay because it gives a good range of time to choose from.
Here is the way I wired it.
*The 87A terminal has to be wired as a switch. It is the deactivation(turn off) that starts the timer sequence. If you wire it so that the ignition turns off all your switches when you turn the key, it will start the timer from that point. If you wire the switch from continuous power, you will have to manually turn it off to start the sequence.
*The 86 terminal is for a ground wire that is interrupted by a switch to start the sequence. So you have a choice of wiring the activation mode, either positive or negative(not both).
The one thing I am not sure about is, if you use the negative terminal with a switch, do you use constant power to 87A??? I never wire a relay this way so I don't know if this applies in this case? Electronic guys???
*The 85 terminal is wired to ground.
*The 86 terminal is a 15amp fused constant 12 volt source(hot all the time).
*The 30 terminal is wired one of two ways. One is it can go directly to the source(fan(s), pump,or both). Since this is a relay you can chose this route. I chose to wire mine to the coil circuit of another relay that will control the two 5" fans in the engine bay. They only draw 5 amps each, but I feel better this way.
When I tested the relay and fans, it worked perfectly. The timer was set for 1.5 minutes(you don't know because the timer has no pointer). You have to use a tiny screw driver to adjust the time. It seems like there ought to be a button with a pointer on it, but it doesn't, so you have to trial and error it to get the time you want. Jack and some of the others have theirs set at 2 minutes. I am not so sure that is enough, so I will start with 3 and see. If it needs adjusting I can do it easily enough.

I want to mention in passing that whenever I add a circuit, or completely wire a car, I use a 12 volt power supply to test the circuit(s). Mine is a Pyramid 6 amp unit
pyramid 12 volt power supply - Google Product Search
and they come in different amperages. All come with circuit breakers and it makes a safe way to test any circuits you are building/adding before attaching that 150 amp battery. If there is an error, or a mistake, or a wire comes loose, the circuit breaker could save you a whole wiring harness.

Bill

Thanks for the note Bill.

wbmusarra said:

.... if you use the negative terminal with a switch, do you use constant power to 87A???

Click to expand...

Their drawing implies that if you are not using one of the trigger inputs you can just leave it unconnected. Open pins make me nervous, so I would probably wire it to +12 just to be safe. The consquences of some "noise" triggering the thing is that your fan runs when it shouldn't, so I suppose it's no big deal (unless of course your hand is in there at the time). OTOH, you don't know how much current it's drawing through that input.

The data sheet for this product should, but does not, provide information that would allow you to make that decision rationally, such as the input resistance of the input, the trigger treshold, etc. I've requested that info and if I get a useful answer I'll post it.

Good thinking on the additional relays. The original SPFs came with fans of around that rating but were later found to need ones drawing about 20A each.

A bit late coming into this thread, but for others - consider using a heated rear window timer.

In the UK, Vehicle wiring products do one (pn GLR10) for £11.02 which has a 10 minute timer built into it.

I have had my time off set for 2 minutes, that all it really takes to take the heat sink out of the engine, on a hot day the fans might be running when the car is turned off but they cycle off before the 2 minutes of pump running is over.

For you SPF guys, there is some extreme wiring mods to make the fans trigger through the SPF supplied relays. If you look closely at the schematic you will see that when the AC is on the fans are in series with each other which makes them run at half speed. So you must take that into consideration before you tap into the relay that controls the fans for engine cooling. With the AC switch on it will blow a fuse in a hurry.

Ebay is a good source for these type relays real cheap.

Quick question on these "run on" timers

Drive up to traffic lights and have a blonde moment and stall the car
Switch off ignition, then turn on again and crank it over (Ignition switch will not allow to move to "crank" position to avoid cranking with a running engine)- will the "run on " sequence be put in motion or will it work as it is being driven?

Ian