Gadget Download

 

 

 

 

 The Design

The diagram shows the proposed single phase water jet pump controller circuit consisting of water level sensors using reed switches, and a transistorized set reset latch stage.

 

I have already explained  how to make reed switch based water sensors also called float switches, you can refer the linked article for a detailed info regarding the same.

 

The transistorized latch circuit is made through a couple of transistors which are designed to latch and delatch in response to the relevant reed switch operations.

 

The two reed switches as shown in the diagram are positioned to sense the high/low water levels, when the water level is low, the magnetic float is held near the lower reed switch, and when the water level reaches the top of the tank, the magnetic float approaches the upper reed switch. During both these occasions the relevant reed switch is actuated.

At the upper water level, the upper reed switch closes which in turn latches the transistor latch circuit, activating the relay.

The relay contacts then switch ON the connected single phase jet water pump motor.

The jet motor begins emptying the tank, until the water level reaches the lower threshold which actuates the lower reed switch, quickly breaking of the transistor latch.

With the latch disabled the relay is switched OFF. This action immediately stops the jet pump motor, until the tank is filled again upto the top to initiate the switching cycle.