What Is an Automatic Water Pump?

Posted on Nov 13, 2020

Automatic Water Pump

The automatic water pump has a water level regulator circuit and is a simple technical structure. Depending on the water level in the tank, it can automatically turn on and off the pump kit. You can implement this motor driver circuit at home or in college using cheaper components.

The main advantage of this automatic water pump level controller circuit is that it automatically controls the water pump without user intervention. The heart of this pump driver circuit is the NE 555 IC; Here we manipulated a flip-flop inside the 555 timer IC.

The automatic water pumps share a similar construction to a regular pump, but with a few modifications and accessories attached. Its design consists of two water level sensors, one attached to the top and the other to the bottom. The operation of this circuit is almost similar to a bistable multivibrator-type automatic water pump.
 

How do Automatic Water Pump Level Regulators Operate?

We know the property of the 555 timer IC, ie Its output power is HIGH when the voltage on the second pin (the trigger pin) is less than 1/3 Vcc. We can also reset the IC by applying a low voltage to the fourth pin (reset pin).

In this construction, the 3 lines are immersed in the water tank. Let's define two water levels - lower (low) and upper (upper). One of the wires or probes is from Vcc. The probe from the lower level is connected to the trigger pin of the 555 IC. So the voltage on the second pin is Vcc when it is covered with water.

When the water level drops, the second pin is disconnected (intact) from the water, ie the voltage on the trigger pin drops below Vcc. Then the output power of the 555 becomes high. Output 555 is fed to the BC548 transistor, which energizes the relay coil and turns on the water pump assembly.

When the water level rises, the upper-level probe is covered with water and the transistor is turned on. Its collector voltage reaches Vce (sat) = 0.2.

Low voltage on pin 4 resets the IC. So output 555 becomes 0V. Therefore, the pump will stop automatically. For a simple demonstration of this design, you can use a DC motor directly on the 555 output instead of a relay.

For practical implementation, you need to use a relay. The rating of the relay is selected depending on the load (engine). A 32A relay is best suited for domestic applications.

This is the water pump automatic control circuit that controls the water pump motor. The pump starts automatically when the water in the upper reservoir (OHT) falls below the lower limit. Likewise, it turns off when the tank is full.

Built around only one NAND gate chip (CD4011), the circuit is simple, compact, and economical. It runs on a 12 V DC power supply and consumes very little power. The circuit can be divided into two parts: the driver circuit and the indicator circuit.

 

:: Read More: Electronic Water Pump: For Home or Occasional Use

Automatic Water Pump Driver Circuit

Consider the two reference probes "A" and "B" inside the tank, where "A" is the lower limit probe and "B" is the upper limit probe. A 12 V DC power supply is fed to the C probe, which limits the minimum amount of water always kept in the tank.

The lower limit of "A" is connected to the base of a transistor T1 (BC547) whose collector is connected to a 12V power source and the emitter is connected to RL1. Relay RL1 is connected to pin 13 of NAND gate N3.

Similarly, the high limit probe "B" is connected to the base of the transistor T2 (BC547), the collector of which is connected to a 12V supply, and the emitter is connected to pins 1 and 2 of the NAND N1 gate and ground through the resistor R3.

The output pin 4 of the NAND gate N2 is connected to pin 12 of the NAND gate N3. Output N3 is connected to input pin 6 of N2 and the base of transistor T3 through resistor R4. The motor is controlled by the RL2 relay connected to the emitter of the T3 transistor.

 

Working Principle of Automatic Water Pump Circuit

If the reservoir is filled below probe A, transistors T1 and T2 are non-conductive and output N3 becomes high. This high power output powers the RL2 relay which drives the engine and starts pumping water into the tank.

When the tank is full above probe A but below probe B, the water inside the tank provides the base voltage to drive T1, and RL1 is energized to keep pin 13 of gate N3 high. However, the water inside the tank does not supply the base voltage to T2, so it is not conducive, and the logic built around the NAND gates N1 and N2 outputs a low voltage to pin 12 of the N3 gate. The net effect is that the efficiency of the N3 remains high and the engine continues to pump water into the tank.

When the tank is full to probe B, the water inside the tank continues to supply the base voltage to transistor T1 and relay RL1 energizes to set pin 13 of gate N3 to high. At the same time, the water in the tank also provides the base voltage to drive the transistor T2, and the logic built around the NAND gates N1 and N2 sends high to pin 12 of the N3 gate.

The net effect is that the output at pin 11 of N3 drops and the motor stops pumping water into the tank. So if you want an automatic water pump control mechanism this is the way to do it fast and easy way.

 

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