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Need LED load indicator

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highveelocity

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I have 2 electric fuel pumps on my diesel and I want to monitor wether they are pulling a load or not. I can put a 12v led on the power wire going to the pump, but that will only tell me if the pump is getting voltage. I don't want to put an ammeter in to tell me how many amps its pulling, is there a way to wire am led in there somewhere to let me know that the pump is actually pulling amps? Thanks for any help
 
You can use an level sensor circuit to determinate the level of the fuel and stop the pumps .

I don't really need to be able to stop the pumps. My injection pump will die with less than 5psi being fed to it by the electric pumps. I have a fuel pressure gauge, but I would like to be able to glance over at the leds to make sure the fuel pump(s) actually have a load on them, which should mean that they are actually pumping fuel. Kind of redundant to have a fuel gauge and the led's, but i would still like to have it.:)
 
How about a pressure switch and led?
 
I have 2 electric fuel pumps on my diesel and I want to monitor wether they are pulling a load or not. I can put a 12v led on the power wire going to the pump, but that will only tell me if the pump is getting voltage. I don't want to put an ammeter in to tell me how many amps its pulling, is there a way to wire am led in there somewhere to let me know that the pump is actually pulling amps? Thanks for any help

Why not put a very small sense resistor in series with the pump wire and an op amp to sense voltage across the resistor? The op amp could drive an led to let you know when current is being pulled. You can even set the sensitivity to indicate a threshold of current if you wish. You don't want too big of a resistor, so that the voltage drop won't affect the pump.
 
Why not put a very small sense resistor in series with the pump wire and an op amp to sense voltage across the resistor? The op amp could drive an led to let you know when current is being pulled. You can even set the sensitivity to indicate a threshold of current if you wish. You don't want too big of a resistor, so that the voltage drop won't affect the pump.

That sounds like exactly what I need. Could you provide a little more info so I can find the stuff you're talking about? Thanks!
 
You could do the same thing with a thick coil of wire around a reed switch. It would take some "fiddling" to get the correct current trip point, but it is dead simple.
EDIT: I like MicroTexan's idea the best because you can still have current being drawn from a stalled pump. To use the current sense idea properly, you'd need to sense for both over AND under current situations.
 
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