Electrical current to monitor pump health

[aryth]

I am thinking about using electrical current sensing/sensors (e.g., in some of the aqua-controllers) to monitor health of the system. For example, if pump is failing or something is blocking a water line, or there is higher water level to push against, the current of pump should increase, and, on another hand, if the head pressure drops, e.g. level drops, or some tubing got undone, the pump's current should decrease.

I would think that some applications, like inferring the water level, may require fine current measurements. Unfortunately, I could not find any technical info on resolution and range of the current sensor used in GHL, Apex, or any other controller and "smart" power strips that I've seen.

So, did anyone try to do something similar, or was thinking about it?
In particular your experiences with related equipment/controllers or DIY projects.

 

[rgulrich]

A side note from Reeflo concerning their pressure pumps (I'm running a Hammerhead/Barracuda Hybrid):
"There is no problem closing down the discharge-it actually makes the motors run slightly more efficiently and cuts a few watts off-however if you cut it back by more than 1/3 you should consider a smaller impeller (just like downshifting gears) to save significant wattage."
Basically, increasing the head pressure reduces wattage consumed. Not sure if this is true of all pumps, but thought I'd let you know.

Cheers,
Ray

 

[Paul B]

Blocking the flow or even partially blocking the flow of a submersible water pump, or almost any water pump will not increase the power requirements. Those centrifical pumps will actually use less current if you block them because the water in the impeller housing will just spin around without doing any actual work. When the pump is pushing water it is harder on the pump as it is doing work and the water entering and exiting the pump will tend to try to slow it down and use more power. Thats why most older powerheads had an adjustment that you could limit the intake water as tit did not cause the pump to overheat, just the opposite.
You can put a presure switch on the outflow that would alert you if the pump was clogged or overheated.
(electrician 40 years)

 

[rgulrich]

Thanks for the explanation Paul!

 

[TheYellowSnow]

yea its a common misconception. If you throttle the output of the the pump it uses less electricity and runs cooler. You should throttle it instead of bleed it if your return is to big. Only the output never the input.

 

[aryth]

Thanks. This is good info.
I can still monitor unusual change in the current, but inferring the cause will be trickier, I guess.