Hi,
I'm not sure how to phrase this in electronic terms - I have a 1930s SU fuel pump that works with a solenoid attached to a diaphragm. When powered the solenoid draws the diaphragm towards it, but also closes the points connection so the diaphragm returns to it's normal position - creating a pull/push of the fuel forcing it through the one-way valves.
This creates a characteristic 'click' which experienced drivers listen out for when they start their cars. Normally it 'clicks' every few seconds but if there is a problem it can stop altogether or click several times a second (and ends up spraying fuel over the engine!).
So I guess the electronics description is an electromagnet relay which is getting its supply via it's own normally-closed relay points... right?
My problem is I want to add a light in the dash for every click.. this is what I've tried:
I added an LED in parallel to the points, but it only lit when I connected/disconnected the relay manually - when it clicked at its normal speed there was no light.
So I added a 2200uF capacitor in parallel, thinking it would be charged in an instant and keep the LED on for a second. Again - manually operating the relay and its perfect but in normal operation nothing lights up. I then added a diode to make sure the capacitor wasn't discharging through the fuel pump... no change.
I'm beginning to think that the LED start up time and the capacitor charge times are much larger than the solenoid connection time and there's no way this is going to work. Is there anything else I can try? The only rules are it needs to cope with a rather electronics-unfriendly 6V-9V range full of transistor killing HV surges...
Thanks...
I'm not sure how to phrase this in electronic terms - I have a 1930s SU fuel pump that works with a solenoid attached to a diaphragm. When powered the solenoid draws the diaphragm towards it, but also closes the points connection so the diaphragm returns to it's normal position - creating a pull/push of the fuel forcing it through the one-way valves.
This creates a characteristic 'click' which experienced drivers listen out for when they start their cars. Normally it 'clicks' every few seconds but if there is a problem it can stop altogether or click several times a second (and ends up spraying fuel over the engine!).
So I guess the electronics description is an electromagnet relay which is getting its supply via it's own normally-closed relay points... right?
My problem is I want to add a light in the dash for every click.. this is what I've tried:
I added an LED in parallel to the points, but it only lit when I connected/disconnected the relay manually - when it clicked at its normal speed there was no light.
So I added a 2200uF capacitor in parallel, thinking it would be charged in an instant and keep the LED on for a second. Again - manually operating the relay and its perfect but in normal operation nothing lights up. I then added a diode to make sure the capacitor wasn't discharging through the fuel pump... no change.
I'm beginning to think that the LED start up time and the capacitor charge times are much larger than the solenoid connection time and there's no way this is going to work. Is there anything else I can try? The only rules are it needs to cope with a rather electronics-unfriendly 6V-9V range full of transistor killing HV surges...
Thanks...