p.mole1 Posted February 27, 2019 Share Posted February 27, 2019 I am having issues with switches burning out, they are switching a 9w solenoid. Am I right in thinking the initial contact of the switch to energize the solenoid will case a current spike momentarily. It looks like it has been arcing? Link to comment Share on other sites More sharing options...
revilla Posted February 27, 2019 Share Posted February 27, 2019 It's probably arcing on disconnect rather than connect ... the inductance of the solenoid will produce a voltage spikes that tries to maintain the current when the circuit is broken. You could try putting a diode across the solenoid, cathode (negative terminal, usually marked with a stripe) to the positive side so it is reverse biased when the solenoid is on. A general diode like a 1N4001 would do the trick. Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted February 27, 2019 Area Representative Share Posted February 27, 2019 It's more likely to be burning due to arcing when the switch opens, as the magnetic field of the solenoid decays, a reverse high voltage is produced.Connecting a diode in parallel with the solenoid will dissipate this voltage.See here:-https://en.wikipedia.org/wiki/Flyback_diodeAdditionally, I'd also be inclined to use the switch to control a relay, and use the relays switch to control the solenoid (as a relay will be far cheaper than the pressure switch!) Link to comment Share on other sites More sharing options...
revilla Posted February 27, 2019 Share Posted February 27, 2019 Well that's two votes for the same solution! Link to comment Share on other sites More sharing options...
p.mole1 Posted February 28, 2019 Author Share Posted February 28, 2019 Great thanks for the explanation. Link to comment Share on other sites More sharing options...
p.mole1 Posted March 8, 2019 Author Share Posted March 8, 2019 I got the car running today and checked the Accusump and all seemed fine although I am using a a much smaller adjustable oil pressure switch ( much cheaper only £20 ). Although I am going to be supplied with a new pressure switch.When I switch on the ignition the relay is working and the soleniod opens however when it reaches the the switches preset pressure, around 35psi I can hear the relay chattering many times a second as the pressure drops and builds again to around 35psi. This seems to have knackered my oil pressure switch, it is a very small 1/8 NPT switch so it must have very small contacts. I'm assuming relay chatter is not good but I didn't think it would kill my switch as the load is reduced by the relay.Any ideas ? I got the switch working by fiddling with the terminals but it's intermittent so I assume I've killed itHow would I stop the relay chatter, does it matter. The Accusump switch is a much beefier switch but I don't want to knacker that one. I'm assuming that the switch must be opening and closing many times as it reaches the pressure threshold regardless of whether it using a relay or not. Link to comment Share on other sites More sharing options...
revilla Posted March 8, 2019 Share Posted March 8, 2019 Do you have a wiring diagram for the AccuSump system? Something really doesn't sound right. Link to comment Share on other sites More sharing options...
p.mole1 Posted March 8, 2019 Author Share Posted March 8, 2019 img032_2.pdf I'll try and send one tomorrow I'm off to Kielder observatory shortly Link to comment Share on other sites More sharing options...
p.mole1 Posted March 9, 2019 Author Share Posted March 9, 2019 Here is the Accusump wiring Link to comment Share on other sites More sharing options...
p.mole1 Posted March 9, 2019 Author Share Posted March 9, 2019 This is how I wired in the relay. When you switch on the ignition you can hear the relay click as the pressure builds in the engine, when it reaches around 35psi the switch must close and the relay opens, pressure drops and the relay opens again this happens in quick succession until the pressure inside the Accusump drops below 35psi.The engine has not been started, I use the the Accusump to prime the engine with oil. I have no Idea what goes on when once the engine is running. I assume when I am using the car on the road nothing happens as I don't think I ever suffer oil surge and my oil pressure is above 35psi on tick over.On a track day the switch may opening and closing many times a second as it reaches th 35psi threshold. Link to comment Share on other sites More sharing options...
revilla Posted March 9, 2019 Share Posted March 9, 2019 Where in the oil system are the pressure switch and solenoid valve installed? Link to comment Share on other sites More sharing options...
revilla Posted March 9, 2019 Share Posted March 9, 2019 I'm really struggling to understand how it's supposed to work. Reading the installation guide online: "When the toggle switch is in the on position, the electric valve will be open whenever the ignition is on with standard electric valves, and when the ignition is on and the oil pressure is low with E.P.C. valves.". So with the EPC valve, the solenoid is designed to shut off when the engine oil reaches 35psi? But the engine won't hold oil pressure when not running, oil will just flow out through bearings etc. and the pressure will fall of rapidly. Then the valve will open again. Which is exactly what you are seeing ... from the description I would expect it to do what you are saying it does, but it doesn't make a lot of sense! We must be missing something. Is there anyone out there who has wired one of these up successfully? Link to comment Share on other sites More sharing options...
p.mole1 Posted March 9, 2019 Author Share Posted March 9, 2019 The system is designed so that when the oil pressure drops below 35psi the accumulator will supply oil additional oil pressure ie oil surge. It works to a point and will supply a limited amount of oil for a few seconds.My problem is the system works for a while but it is burning out the pressure switch, this is a common problem if you trawl American car sites. I used a relay to try and reduce the load on the switch contacts. I don't think it is a very good system but I could use it without a pressure switch. It would just act as an additional reservoir, however the oil gets hot on a track day and it will be dumping oil into the sump as pressure drops increasing crank drag and making oil temperatures worse.A dry sump would be the ideal solution but I can't justify/afford one, and if I wreck this engine that will be the end Caterham ownership I am told by a higher power. Link to comment Share on other sites More sharing options...
elie boone Posted March 10, 2019 Share Posted March 10, 2019 An option would be to use a toggle switch instead of the pressure switch, you then would have to "close" the accusump before you switch off so that it keep pressure, you also would have to switch it on just before starting, another advantage could be that all the oil would gradually warm up and you will need to check levels with a running engine. Link to comment Share on other sites More sharing options...
revilla Posted March 10, 2019 Share Posted March 10, 2019 How about running your relay off the fuel pump relay drive? Then you would get a couple of seconds of pre-oil when you turn the ignition on and the AccuSump would turn on when it the ECU detected that the engine was actually turning and stop with the engine, rather than with the ignition switch. Link to comment Share on other sites More sharing options...
p.mole1 Posted March 10, 2019 Author Share Posted March 10, 2019 Good ideas, I don't think the system works to well with cold oil and I might just leave it switched off unless I do a track day.I quite like the idea of pre oiling an engine, but I don't suppose it makes much difference for the amount of miles I do. I am going for a belts and braces approach and have managed to get hold of an Apollo tank second hand on ebay Link to comment Share on other sites More sharing options...
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