Lab Report 7
Introduction
The electrical motor is the device, which converts electrical energy into the mechanical energy. It is must to analyze the characteristics of electric motor. The electric motor is always considered as the dynamic device, which changes its performance influenced by various factors. It is necessary to analyze the important electrical parameters of the electric motor, in order, to use the electrical motor for the particular applications. The electric motor is used in the applications like pumping, home appliances, lifts, cranes, etc. This report discusses about the construction of the electrical motor, and mainly, it discusses about the motor parameters, like rated voltage, breakdown torque, and starting torque.
Construction of the motor:
The stator of an induction motor consists of poles carrying supply current to induce a magnetic field that penetrates the rotor. The best estimate of the air gap between the stator and rotor is about half inch. The rated speed and hp of the motor is 170.5 KHP. On the other hand, there are 12 poles in this motor and the synchronous speed and full-load slip of the motor is 175W.
Motor characteristics at rated voltage:
When we connect the circuit according to our schematic, we measured and recorded the motor line voltage, three line currents, two wattmeter readings, and the speed:
For no-load operations, we calculated the slip, real (active) and reactive power, power factor, and the motor efficiency:
The second step was to set the torque control knob all the way counter clockwise. Also, we did the same, we measured and recorded the motor line voltage, three line currents, two wattmeter readings, and the speed:
Then we measured and recorded the motor line voltage, three line currents, two wattmeter readings, and the speed for the following load torque settings:
At the end, we measured and recorded the speed regulation, efficiency, and power factor for the full-load of the motor:
Motor characteristics at reduced voltage (150V):
We measured and recorded the motor line voltage, three line currents, two wattmeter readings, and the speed for the following load torque settings:
Breakdown torque:
We set the load control knob all the way counter clockwise, and then we slowly increased the voltage to 130V. Increasing the load torque slowly to 0.5Nm. As increasing the load, the aped will drop. We recorded that the motor speed at 0 is 17.11 and the motor speed at 0.5Nm is14.33.
Starting torque:
We used 8A range for ammeters with using the fixed 3-phase/208V supplies instead of the variable 0-208V source, we set the load control knob to MAX position. We measured and recorded line voltage, line current, load torque, and speed:
Discussion
The motor supplies the current to form the magnetic field that prevalent through the rotor. The important motor parameters are the voltage, line, current, and the wattmeter readings of the speed measured. The efficiency of the motor is been zero, with the low speed regulations values. The motor faces the lagging power factor; the value is very low 0.45. While testing the breakdown torque the load control knob is set in the counter clockwise direction and then the voltage is slowly increased. The load control knob has been set in the maximum position. The motor efficiency is about 46% in the no load operation. The motor power factor is very low it is 0.18, which is bed for the motor operation in the no load condition. The motor supplies the reactive power of 21.26Var in the no load condition.
Over motor parameters has been analyzed in this report. The motor shows different characteristics in the different conditions. The motor characteristics can be studied completely using this test. The motor test is carried out successfully in this test.
