DESIGN OF THREE PHASEINDUCTION MOTOR PROTECTION CIRCUIT FROM SINGLE PHASE FAULT AND OVER HEATING AT URAFIKI

PROBLEM STATEMENT

Three phase induction motor running with two phases instead of the full balanced three phases causes the two operating phases to carry much current as the load increases, the motor will keep on running until due to the excessive current onto the two phases leads to the generation of much heat onto the motor active winding leading to the complete shutdown of the system due to motor failure caused by the complete melting of the motor winding, or overload make motor off

MAIN OBJECTIVE

This project will be used to protect three phase induction motor from single phasing and overheating problems which in turn will improve the efficiency of motor. Hence it ensures the net production of the plant to be almost positively constant.

SPECIFIC OBJECTIVES

• Studying the existing system.
• System circuit design with converter circuit.
• To run the simulation of the system and observe expected output.
• Prototype construction.
• Prototype testing and report writing.

SIGNIFICANCE OF THE PROJECT

• Prevented a total shutdown of the system.
• Minimize annual costs for motor rewinding
• Reduce unnecessary downtime.
• Improves total equipment and operator’s safety.
• Increases total profit for the firm if it is a commercial business (e.g. (industries).

DATA  ANALYSIS

ATMEGA 328P

The Atmel 8-bit AVR RISC – based microcontroller combines 32 KB ISP flash memory

23 general purpose I/O lines, 32 general purpose working register,

three flexible timer/counter with compare models,

Internal and external interrupt, serial programmable.

POWER SUPPLY 

The supply voltage from main power supply is 220Vac to 240Vac at a frequency of 50Hz which enters into the primary side of the transformer and the output voltage from the secondary side of the transformer is 12Vac.

𝑉𝑝/𝑉𝑠=  Np/𝑁𝑠   =240/12  =20:1 

    Transformer ratio will be 20:1

Bridge rectifier convert 12output voltage of the transformer to DC

Vpeak(out) = 1.414 ∗ 12v = 16.968Vac

Vpeak(out) = Vpeak(sec) − 1.4v=15.5

PIV for each diode = Vpeak(out) + 0.7v = 16.2v

Unfiltered dc (Voltage Peak Rectified)

Vpeak(rect) = Vpeak(sec) − 1.4v

= 15.55v − 1.4v =14.15v

Taking ripple factor of 3.97%,then capacity will be 20μF

Pure dc (filtered dc),

𝑉𝑑𝑐=(1−1/〖2𝑓𝑅𝐶〗^((4.4) ) )∗𝑉𝑝𝑒𝑎𝑘 = 12.18V

Liquid crystal display

Power supply is +5V

Number of character is (64.5 width * 13.8 height )mm

Effective display area 16 character * 4 lines

Character size (5*7 dots) is (3.07 width *5.73 height)mm

Dot size is (0.55width * 0.75height)mm

Operating temperature 0 to 50ᴼC

circuit diagram of the proposed system