relay to control exhaust cutouts
Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=123451
Printed Date: April 28, 2024 at 12:04 AM
Topic: relay to control exhaust cutouts
Posted By: green can
Subject: relay to control exhaust cutouts
Date Posted: September 10, 2010 at 4:30 PM
i have 2 jegs elect exhaust cut outs that i want to control via atemp sensor the switch that came with the kit is a rocker switch and both legs are hot at all times. keeps amps from going thru switch switches the ground on 1 leg or the other when rocker switch is moved when not moved both wires going to cut outs are hot all the time will this diagram work for my application also i need a 1 sec pulse so what res/cap do i need
Replies:
Posted By: dualsport
Date Posted: September 13, 2010 at 4:30 PM
Can't quite figure out what you're looking for here- what kind of temp sensor were you planning on using, and when is the exhaust cutout supposed to be activated? Is this to open up the exhaust when something gets hot?
Why do you need a 1 sec pulsed output?
Posted By: dualsport
Date Posted: September 13, 2010 at 4:38 PM
So it looks like your exhaust cutouts are just a motor controlled valve that open and close based on the polarity of the input, like a window motor, which is what led you to the window circuit-
The question then becomes what is the temp sensor you were going to use, and how. From there you can condition the signal appropriately to do what you want.
Posted By: green can
Date Posted: September 13, 2010 at 5:43 PM
185 degree temp and yes to open up the cutouts 1 sec because it takes 1 sec to open them when i push the switch
Posted By: green can
Date Posted: September 13, 2010 at 5:58 PM
yes they are a basic motor control valve that i want to open/close with the switch the came with and i want them to open when my 185 tep tells them to and close when temp cools down
my question is what cap/res i need for a 1 sec pulse and can my neg wires switch back and forth going to the capactiors like i have them
im going to radio shack 2 morrow to get cap /resistors wowever im really confused on the resistors colors and what the colors mean i read about them on this site and now im really confused
i looked up a 10 fixed resistor online and there is many difrent 10k s out there?
Posted By: dualsport
Date Posted: September 13, 2010 at 9:45 PM
Is this temp sensor you're talking about actually a temperature switch that closes to ground above 185 degrees? That would be the first thing to check before going on further. So you want the exhaust cutout to actuate when the switch turns on, and close up again when it cools off?
Posted By: green can
Date Posted: September 13, 2010 at 10:30 PM
yes ihe temp switch is a open close hi limit switch for pressure washers
my pressure washing van uses a hydraluic clutch pump off the van engine / burns half the fuel a 13 hp honda does in return works a hyd water pump@ 3500 psi im using exhaust cutouts on my exhaust for my heat exchanger free heat the heat exchanger works gr8 heats up 6gpm with no problem
1 cutout opens as 1 is closed all engine heat bypasses factory exhaust and goes thru heat exchanger if water gets to hot then it needs to close and then go thru factory exhaust as not to become a bomb or blow a hose up
the problem is when im not pulling on the triger the water gets over 200 super fast and the pressure jumps up and will set off the 4500 psi blow out disc
Posted By: dualsport
Date Posted: September 14, 2010 at 7:54 AM
Interesting application-
How critical is the pulse time for switching the cutouts open and closed? And how often does this cycle? As long as the switch doesn't cycle too fast, to allow enough time for the circuit to reset for the next pulse.
You need a pretty large cap to get a one second pulse time, the actual time is affected by the relay coil draw. It's simpler to do it like this, but you might consider using a transistor driver instead, so it won't need the large caps. Also it makes it much more easily adjustable. With the direct drive setup, then only way to adjust the timing is to buy another big cap, if it turns out the pulse isn't enough to cycle the cutouts fully. Depends how much you want to avoid using solid state components.
You could just try to find a larger cap like 4700uF and experiment with the relays you're using, and see if the timing will work out okay. You'll probably want to go double the time it needs to cycle the cutouts, just to make sure they close fully.
Posted By: green can
Date Posted: September 14, 2010 at 8:38 AM
i would guess 5 min between pulses main goal is not to burn out the motor on the cutouts as they were $250 like any other elect motor if i keep trying to make it turn when it cant via full open or full closed it will burn up
what is a transistor driver ? where do i get them? and this does sound like what i need
thanks for your help
Posted By: dualsport
Date Posted: September 14, 2010 at 6:33 PM
No problem with 5 minutes, so you should be good there.
Definitely don't want to have the motor drive current get locked on when it's already at the stops, but is there any problem if it gets a partial pulse, and doesn't close fully one way or the other? Would that cause the cutout valve to burn up also? I'd guess that could be just as bad.
As far as the transistor driver, you could build a circuit pretty cheaply, but if you haven't worked with electronic circuits, you might look into using one of the timer modules that are commercially available, just to play it safe.
It'll cost a bit more than a DIY circuit, but might be a better way to go to reduce the risk of something failing and locking up on you. One of the regular guys here like howie, KP, spark, or iam are more familiar with the particulars and probably could point to the best source for the timer modules, which you'd use to get a momentary output when it gets a transition trigger.
The momentary output is what you'd use to drive the relays in your circuit to switch the motor current, and you'd need two separate timer modules, one for each relay.
Posted By: green can
Date Posted: September 14, 2010 at 11:03 PM
yes your correct i Definitely don't want to have the motor drive current get locked on when it's already at the stops if it gets a partial pulse, and doesn't close fully one way or the other that is no good either heat exchanger could heat up while driving down the road
so how do i get in touch with this howie fella in reference to a timer modules that are commercially available ?
i went to my buddies welding shop and we installed the exhaust cuttouts and heat exchanger 2 day pain in the butt however its done now i need the elects to work
Posted By: dualsport
Date Posted: September 15, 2010 at 12:12 AM
There's a bunch of posts about the DEI 528T timer, this one mentions an application similar to yours- think ckeeler posted a good price source for them, but don't remember where it was.
https://www.the12volt.com/installbay/forum_posts.asp?tid=110810&DIR=N&fid=5
Posted By: green can
Date Posted: September 19, 2010 at 5:50 PM
i got it working how do i close topic
Posted By: dualsport
Date Posted: September 19, 2010 at 6:12 PM
Don't worry about that, it'll be taken care of soon enough-
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