pump protection

A combination of pressure switch and flow switch in the suction line.

It is bit more complicated, but you can use CT based relays which sense the drop in current and trip the motor.

Cheers.

Hello sparkyspark

Your 400 foot elevation increase is going to require approximately 185 lbs per square inch pressure just to get the flow to the outlet at the top.

Remember to add the pressure required at the outlet, plus the loss in the suction pipe to the pump from your water supply, plus the loss in the outlet pipe from the pump, plus the pump loss.

With a 1.5HP pump, there is not going to be a big quantity of water actually moved, as most of the motor effort will be absorbed by the various losses.

For this type of installation, once pump size/motor size/pipe size has been determined, it is sometimes better to add to chaterpilar's system with an electrode sensor in the supply pipe, just before the pump.

No water = motor shutdown, and alarm sent, if required.

If you are supplying a header tank at the top of the outlet pipe, the simplest auto control is a ball float valve, which shuts the pump off with the increase in pressure as sensed at the pump outlet.

When the tank level falls, the ball float drops, valve opens, pressure switch at pump outlet senses pressure drop, and switches the pump motor on.

Trust that assists you.

Kind Regards....

There are devices that measure the phase angle between the voltage and the current of a motor. If these go out-of-phase by more than a pre-set amount, a changeover contact operates. The contact can be used to interrupt the starter circuit, and trip the motor out. One of these has been used quite satisfactorily to indicate a switch-off point for a pump in an industrial water treatment plant. It's a neat solution where nothing can be installed in the process line.

Another way is to put a pressure switch on the pump inlet line. If the pressure falls below, say, 20psi (user adjustable) then the switch could be used to switch off the pump.

this pump has been operating using the breaker as a switch with a high pressure limit in line. I suppose a flow switch with a delay might be the answer. Isn't it possible or likely that a low pressure switch would cause bounce/nuisance stops once a starter is installed? Trying to find a conventional proven solution instead of reinventing the wheel.

I normally fit a pressure switch on the supply side or a dp switch across the pump for this application

Hi There,

There are pump control units you can buy which automatically shut the pump down when the unit senses cavitation or interruption of the water supply, there is not much use in fitting a pressure switch on the intake or supply side of the system because it is under suction. I bought a unit in Australia for $95.00 AUD & it will automatically turn the pump on & off as a tap or hose is turned on & shut down if there is no water supply to the intake side of the pump.

Have look at www.cheapapumps.com.au

I am presently using the Pumptech plus pump motor protector by Franklin Electric. Works great! http://www.wwpp.us/pumptec/pumptec-plus.shtml?gclid=CMSK_IiVtZQCFRghnAodcgS6Ug

A company called Load Controls Inc has several inexpensive devices, which I've used in various applications. These are easily integrated into your pumps control circuit.

www.loadcontrols.com