In this post I have explained a timer circuit for submersible borewell pumpset which alternately switches the pumpset ON/OFF at a predetermined rate in order to allow the ground water sufficient time to restore at regular intervals and to ensure a consistent water supply to the attached overhead tank. The idea was requested by Mr. Siva.
Circuit Objectives and Requirements
- I want to run a submersible pumpset only in 3 phase with major interval of 1 hour interval duration. There is no available ground water supply for continuous running for the pump.
- So i need a AC circuit to operate automatically timely for 1 hour running & 1 hour idle.
- Please provide a circuit to operate without any drawbacks because if anything happens wrongly need to spend more money & time to resolve it.
- More than that only source of water for us(borewell only).
Pump Specifications
100mm(4")borewell submersible pumpset
Motor
Type:TBRF1545+TF045H
Hp/Kw:6.00/4.50
Power:3 phase A.C
Rpm :2850
PUMP
Type:TBRF1545+TF045H
Hp/Kw:6.00/4.50
Rpm :2850
No.of stage:45
Designing the Pump Timer Circuit
The requested submersible bore well pump timer circuit can be simply built using a single IC 4060 timer circuit and a relay, as indicated below
As may be seen in the above diagram, the IC 4060 is wired as a simple timer circuit whose timing limit is determined by the combined values of C1 and of P1/R1.
P1 can be adjusted for getting any desired delay ON/OFF at pin#3 of the IC, within a stipulated range.
Since the IC is configured as a free running astable multivibrator, the ON/OFF delays at the output pin#3 continues to toggle the transistor driver stage and the relay infinitely as long as power is available to the circuit.
If as per the specifications, P1 is adjusted to obtain a 1 hour ON/OFF delay at pin#3, the relay could be expected to switch ON/OFF at the same rate continuously as long as the circuit may remain powered.
The relay contacts can be seen wired with the 3 phase motor's contactor coil, which correspondingly operates at an identical delay rate during the course of ON/OFF switching.
This results in the switch ON and OFF of the borewell motor at a precise interval of 1 hour, which in turn makes sure that the ground water gets ample time to replenish and enable a sustained water supply for the motor to pump in.
Other time delays may be achieved for the proposed submersible pumpset timer circuit by appropriately adjusting P1, as per the given specifications or the ground water conditions.
Calculating the Time Delay
It could be determined using the formula:
f(osc) = 1 / 2.3 x Rt x Ct
The resistors at pin#10 correspond to Rt
C1 corresponds Ct
