Ncit Final Project (Water Pump Control System)

NCIT

FINAL PROJECT

Automatic water pump control

For My Home

Name: Hasitha Heshantha Rajapaksha

Admission no: 1105 /07 /08

Course: NCIT (Electrical/Electronic)

Lecture:

Date:

Summary

I did this automatic water pump control unit for my NCIT final project. I get the automatic water pump basic controlling idea from our library book. Also I have experience in my home water pump controlling. Because of that I develop this basic idea for my house requirement.

But I can’t make voltage regulating protection unit for this system because I haven’t got variable AC power supply unit for experimenting the required voltage levels for our home use motor. I got the money to build this project from my parent. I have cost around 2500Rs for this project. Most of the parts for experiment work.

I think everyone can make this kind of system for their home requirement easily. Because of that this is simple system for my home requirement. It also gives better controlling over the water level, water line fault finding and voltage regulate protection for our water pump.

Finally I thank my parent who encourages me throughout the development period and financial support. Also I thank my teachers who teach me up to this level and other people who give their experience consultant and support. I hope to add more development to this project and to develop more reliable system.

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Content

1. Summery page 1

2. Content page 2

3. Introduction page 3-5

4. Work carried out page 6-15

5. Evaluation page 16

6. References page 17

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Introduction

In my early day I saw that my parent was keep looking at the water tank over flow when they switch on the water pump. This is a time killing period. If the motor is switch on they can’t move any were or do other extra work without pay attention to the tank over flow outlet. These reasons encourage me to develop a suitable system of water pump controlling for my home. Because of this I develop water level regulating subsystem for this system.

Our sump well and motor house is located 100m-150m away from our home. So if something happen in operation we have to go to that motor house. Also there is another difficult task on our motor operation. That is that Jinasena Centric water pump has a manual thermal overload relay, if this get trip we have to go to motor house and manually switch on it. This is reason I develop Water line sensing and voltage regulating subsystems.

Our motor is initially taken starting current up to 13A and it has a running current of 5A. Because of that I use normal DC operated relay for switching. But if required it can operate through a contactor which operate by that normal relay.

I take simple parts and circuit for this development. I got financial support from my mother. I made my developing circuit diagram through Multisim Electronic Workbench software. It is get easier to make development through that software and experiment on different component. I use project board for practical experience because it reduces the wastage of lead and component.

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I got my basic idea of developing water level regulator and voltage regulator from our library book called Electronic Timers and Practical Applications. I modified some of these systems according to my requirements. Then the water line sensing and relay operating circuits are development of my own. I make that development by watching 555 timer circuits and experimenting on software.

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Picture of our home water Storage Tank (Figure 1)

Picture of our Sump well (Figure 2)

Wide angle view of our home and sump well (Figure 3)

Motor house and below it the well (Figure 4) Water pump (Figure 5)

Thermal overload protection of the motor (Figure 6)Basic idea circuit diagram get from Electronic Timers and Practical Applications Voltage regulator (Figure 7)

Basic idea circuit diagram get from Electronic Timers and Practical Applications Water level regulator (Figure 8)

Work Carried Out

I develop circuit diagram through the Multisim software. I get measurement and objective from observation of the operation of the pump for 2-3 days. First I built up experimented diagram in a project board. By looking at it I made little adjustment and replacement according to practical requirement.

My aims for development

The motor has to have a control on water level on storage tank and sump. It has to operate only when water is available in the sump. Also it has to operate when the water level reach to lower level of the storage tank automatically and it has to off when level reach to top level of the tank.

Ensure a continuous water supply.

There should be manual operation switch for user to operate it between top level and bottom level.

It has to have a dry run protection.

It has to indicate the sump water availability.

If the pump get switch on (voltage at it terminal) and it does not pump the water to tank within 25Sec it has to automatically switch off the motor and has a indication of that fault. Also have to have a user reset button to manual time reset and fault diagnosis. Have indication on them.

System must have a fuse for overload protection.

System has to indicate main power availability and motor switch on.

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All the operation off triggering must have to have small time delays for unwanted fast switching reducing.

The relay must have a ability to width stand large current.

It can easily convert to drive a contractor for large motor application.

By looking at it any one can easily find the operation of it.

The sensing electrode must not electrolyte the water.

Main Block Diagram of the operation

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Common line

Auto On

Manually operated

Allowed

Auto Off

Water outlet

Off flow

Top level sensor

Auto cut off

Auto keep sensing

Common line

Bottom level sensor

Common line

Cut off level Sensor

Water line sensor

Block Diagram (Figure 9)

Theory’s that use

555 Timer operation RC Timer operation AC Electrode (not Electrolyte the water) Opt coupler isolation Darlington Transistor arrangement Freewill diode protection AC voltage indication Zener Diode protection AC-DC conversion Voltage step down DC voltage regulation and ripple rejection

By using these basic theories I made the modification of basic circuit that is taken from the book. Also using these theories I make new circuit for resolving each requirement.

Develop sub systems for each operation

1. AC-DC conversion and Water level regulator using AC electrode for sensing.

2. Water line Fault sensing using AC electrode.3. Final Relay Drive Circuit that Drives according to each subsystem. 4. AC Over current protection and Surge Protection.5. AC Voltage indication.

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Operation

Water level regulator, DC supply, AC Electrode Sensor

For obtain a clear regular DC supply for the unit I used 230V to 12V AC Transformer and Brig rectifier to AC-DC conversion. Then I reduce it ripple using cap. After that I use LM7809 regulator IC for regulating operation.

Then for water level regulation I use 555 IC operations. If 555 IC pin 2 Get high output of pin 3 remain low so isn’t driven the opt coupler and remain none conducting. If water level goes bellow that present level pin 2 goes low and it gets triggered. This will course automating water pumping operation. When water level reaches to upper level pin 6 get high. This will reset the 555 IC and stop the operation.

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Developed Water Level Regulator and DC power Supply Circuit Diagram (Figure 10)

If the water level in the sump goes below the minimum level IC get reset and stop the operation.

The pump can manually operate in the water level between upper and lower level of storage tank by pressing two on and Stop push buttons. Two capacitors connected between pin 2 and ground, pin 3 and ground will prevent false triggering due to line transients.

For AC Electrode sensing it use separate transformer of 18V that gives the power for level sensing. If the brig rectifier gets the voltage via through the water opt coupler get conduct and it will drive the transistor coupled to it. By this transistor it gives the high signals for 555 IC operations. A 10 Ω resistor and 2.4V Zener will protect the opt coupler from high voltages appear through it.

By using these techniques it will give a reliable operation through water level regulation. This operation will not cause any electrolyte action in sensor and water. Because of this electrode may kept for a long time without any chemical reaction.

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Water line Fault sensing using AC electrode

In this it use again 555 IC normal Triggering operations according to sensing line. In here a high capacitive capacitor and high resistance is use to obtain a 30Sec time delay for sensing water line after couple of time when motor start. The AC water sensing line sense the water coming in to the tank and it drive a transistor and keep discharging the capacitor. This will give the required operation. This timing initially start when the pin 2 get high when the water level regulator gives operating signal.

If the water level regulator get stop this capacitor charge also have to reset for a new operation. This is done by discharging the capacitor through water level regulator 555 IC pin 7.

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Developed Water line Fault sensing Circuit Diagram (Figure 10)

Final Relay Drive Stage, AC surge protection, over load protection and AC Voltage indication

In this I use opt coupler to give 3 series signal to drive the transistor that drive the relay. It need complete 3 signals from, water level regulator water line protection and voltage regulator signal to switch on the relay.

For AC line surge protection I use two 0.47µf 2KV capacitors to short circuit live or neutral to ground in the surge condition and trip the RCCB in main unit of the home. A series 13A Fuse is use for over current protection.

For the indication of AC supply I use high voltage AC cap and series connoted LED that connected parallel to output and input of the AC lines.

Voltage regulated operation of the motor

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Developed relay derived and AC protection, indication Circuit Diagram (Figure 11)

* I haven’t develop this circuit practically because I haven’t got a large capacity variable AC supply unit for measuring the required operating voltage level for the motor without tripping the thermal over load relay of the motor.

So I draw it directly by looking at the book

*Some time these theoretical circuits will May slightly different from practical circuit that maid because of availability of parts and practical reasons. I tested most of the develop circuit at ideal condition in the software.

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Voltage regulator protection Circuit Diagram (Figure 12)

Complete unit Figures

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Complete unit (Figure 13)

Upper section of the unit (Figure 15)

Power inlet for unit

G L N

G L N

Power inlet for unit

Power outlet for motor

N L G

N L G

Power outlet from unit

Power to motor indication LED

Power to Unit indication LED

Lower section of the unit (Figure 16)

Top level sensor out

Bottom level sensor out

Cut off level sensor out

Common line out

Common line out

Water line sensor out

Relay operation indicator

Sump water indicator

Water level

Regulator indicator

Water line fault

Indicator

Manual ON OFF Push

Button

Complete unit upper angle view (Figure 14)

Power switch

Water line Fault reset

Push Button

Operation Figures

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Normal operation only the power on without sensing (Figure 17)

Normal operation motor power on (Figure 18)

Normal operation water line sense fault indicating (Figure 19)

Evaluation

This system operates normally when the voltage and sensors is normal conditions. There is only Lack of resource so I couldn’t make the voltage regulate operation sub system. Because of that now it only give the normal operating result when the supply voltage in normal condition.

This system is design to sensing water but with a slight modification I think this can use for other liquids except flammable liquid. Because this system has poor isolation over the air.

The major advantage of this system is its sensors are operating from AC signal. So there is no chemical action in the liquid theoretically. Also this system has new improvement of water line fault monitoring system. This is very important when the pump house is far away from the storage tank.

I think this system will be has lesser initial cost compared with available water regulators in the market. Also in operation it takes only around 500mA current.

By using this system with a contactor it can operate large capacity water pumps. There is space to fit a contractor for this unit. I think use this with a contractor is the best method.

There is some disadvantage over this system that is that the sensing electrodes must not short circuit with the common line. If this occurs it will take more current and will be damage the transformers and sensor unit components.

I think I have reached all the aims that I Target except that voltage regulation system.

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Reference

Electronic Timers and Practical Applications Book Internet Data Sheets

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