I have a sump pump and the float switch is mounted on it, I need a simple solution for knowing when the pump is running (like a light bulb). Can this be done (simply) with only having access to where it plugs in ? and inexpensive. and supplies readily accessible supplies . I would appreaciate any help.

 

You could plug the pump into a current sensing power strip such as this. Then anything you plug into the strip will be turned on when the pump is running.

 

That depends on the current draw of the sump pump which could be rated higher than the smart strip. If the pump arm has a lever that goes up and down, then a mercury switch could be mounted on the arm to trip a light when the arm moves up or down.

A magnetic reed switch could be used if the arm is near a wall mounting position too.

 

If current is to high for strip solution.
These work well.

Run one lead thru opening.
Led lights and switch closes at rated current.

jumpers for 1-200 amps

 

Here's a circuit that uses a U-bolt coil around one leg of the AC line to enable a relay. Seems plausible to me but it might work better with a full coil around the line.

http://circuitsstream.blogspot.com/2012/12/simple-ac-power-current-detector.html

 

Normally a CT should not be operated unloaded, I do not see anything in the circuit to satisfy this?
Max.

 

Would a high value resistor across the ct satisfy?

Is that to keep the theoretical voltage peak in check?

 

There is no visible load or Burden on the CT shown which has a 1:800 ratio as far as open circuit voltage is concerned.
The idea is to measure current.
In a C.T. the voltage is directly proportional to the winding ratio and the current inversely proportional.
So it is necessary to place a load on the secondary, this is why unused C.T.'s have or should have a shorting link across them to avoid the possible high voltages on the secondary.
Max.

 

this sounds like it is getting overly complicated, lol.....

You just need to get another one of the sump pump float switch piggyback plugs, cut off one end and connect that to your light bulb (With the same voltage ratings as your pump), then plug this in between the float switch plug, when the float switch supplies power to turn on the pump, the light should also turn on.....

Or you can get a double outlet and box with a cover, wire your float switch to the outlet so that it will supply power to it when the float switch is tripped, plug your sump pump into one outlet and a lightbulb/lamp in the other... whenever the sump pump comes on, the light will also.

(K.I.S.S. is the simple rule I always try to follow!)

 

Can this be done (simply) with only having access to where it plugs in ?

does your plug look like this??

 

does your plug look like this??
View attachment 64385

If yes, then one of these? And a night light.

I still like the CTs, as it shows definitively that pump is running.

 

does your plug look like this??
View attachment 64385

I bet it does, and if it does, I would do this (with a separate cord) and wrap a secondary around the primary, with just an LED in series. No resistor. Just experiment with the turns until the LED comes on.

 

I bet it does, and if it does, I would do this (with a separate cord) and wrap a secondary around the primary, with just an LED in series. No resistor. Just experiment with the turns until the LED comes on.

I doubt if you can get enough coupling without a core. Have you done this?

 

I doubt if you can get enough coupling without a core. Have you done this?

Nope. I got the idea from these. Had a whole bag of them, different brand, smaller size. Just a coil with an LED.

 

I've lighted an led direct from a CT and even homemade CT (a few turns on a transformer).
Needed a core for my experiments.