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Well Pump Motor Indicator |
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One of
Wily’s neighbors stopped by and described a problem he was having with his water well
pump. The guy really needed Wily’s help. He wanted a simple way to indicate
when the submersible pump motor was turned on and running, so the neighbor could do some
troubleshooting. The water well head and electrical connections were located some
distance from the back of the neighbor’s house, inside a small shed. What the
neighbor wanted to do was turn on a small light whenever the pump turned on.
He wanted the light to be bright
enough so it would be visible from the house. He was not sure, but the neighbor
thought that the pump motor was turned on and off by switches deep down the well.
Therefore, there was not a simple switched voltage to tap into at ground level in the
shed. How could he turn on a light when the pump was running? Wily thought about it
for a few seconds and then told the neighbor that he thought he had a solution. |
The pump motor was about a horse power in size and was powered by 240vac. Wily did a
quick mental calculation and figured that the AC current must be about 6 Amps. There may
not be a switched voltage in the shed but the AC current feeding power to the motor would
sure be detectable. In fact, with the right part, Wily thought he could take
advantage of the 6 Amps of AC current flowing. |
Wily looked though his box of assorted current transformers and found just what he
needed. It was a part made by Triad. The device was small enough to fit in the
pump’s electrical junction box and had a nice plastic clip-on assembly, so Wily would not
have to disconnect any wires. Wily had used this part in other applications so he
knew that with 6 Amps of AC current, the transformer would produce enough voltage to power
a green LED directly with good intensity and without any other power supply. Wily
also looked around in his box of assorted panel lights and came up with a nice weather
tight lamp holder. With a quality green LED installed in the holder, the lamp should
be bright enough to be seen from the house. |
Wily wired up the circuit shown below and made sure that the circuit worked. He
then drilled a hole in the shed, above the access door and mounted the lamp assembly in
the hole. He then soldered the diode and resistor to the lamp holder before running
some wires to the current transformer. When everything was wired up, the light
turned on every time the pump motor clicked into operation. |
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Water Well Shed |
Submersible
Pump System |
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Current Transformer |
Panel Mounted Lamp Holder |
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Self Powered AC Current Indicator |
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