1 . OBJECTIVES
(a) To look for the equivalent circuit parameters of any 3-phase squirrel-cage induction
engine from lab test data.
(b) To determine the performance features of an induction motor beneath load circumstances. (c) To control the no-load speed of the induction electric motor.
2 . ADVANTAGES
2 . you Three-phase squirrel-cage induction power generators
An induction motor is known as a transformer using a rotating extra winding. It includes two important components: an outer fixed stator and an inner rotating rotor. (Figure 1) [pic]
Determine 1: Induction motor
The three-phase induction motors could possibly be categorized in to two main types according to the different rotors: the squirrel-cage induction engines and the injury induction power generators. The squirrel-cage induction motor are commonly used when the insert requires very little starting torque, such as take you and supporters, while the wound induction motor are necessary utilized when the insert requires excessive starting torque. The debut ? initiation ? inauguration ? introduction motor found in this test is a there-phase squirrel-cage induction motor.
2 . 2 Power converter
As it is necessary to modify the ac electricity magnitude in accordance to maintain a constant air-gap debordement, when the motor unit supply consistency is may differ, a power-converter is used in the experiment A power converter is power-electronics based system which can has additionally been power with varied regularity. It first converts the normally offered fixed rate of recurrence ac source to a power supply simply using a rectifier. The dc supply is then converted to a variable-frequency ac supply, which can maintain a constant air-gap flux in the motor simply by an inverter.
2 . several Synchronous acceleration
When the well balanced three-phase currents flow through three-phase stator windings with the motor, a rotating magnetic field or perhaps magnetic motive force (mmf) is definitely produced. The velocity of the rotating mmf is known as the synchronous speed and it depends around the supply rate of recurrence and the quantity of the poles in the engine, as shown in formula 1 .
[pic] (Equation 1)
[pic] rad/sed (Equation 2)
The rotor of the motor tends to stick to the rotating mmf but works at a speed somewhat lower than the synchronous acceleration, because of the a shortage of the induced emf inside the rotor shelves. The disc speed is definitely denoted as Nr as well as the phenomenon the fact that rotor can be continuously falling behind the stator rotating mmf is referred to as slip. The mathematical appearance is proven as beneath
Three-phase inauguration ? introduction motor1 product
DC generator1 unit
Electricity Converter1 device
Power Analyzer1 unit
Three-phase variable resistive load bank1 unit
Three-phase load switch1 unit
5. 1 Nameplate data and preliminaries
4. 1 . one particular Record the nameplate (or rated) data of the electric motor.
4. 1 ) 2 Gauge the resistance every phase (R1) of the stator winding employing power analyzer. 4. two No-Load Evaluation
4. 2 . 1 Make sure that the base of the debut ? initiation ? inauguration ? introduction motor can be decoupled through the shaft with the DC electrical generator. 4. installment payments on your 2 Hook up the three-phase stator winding of the induction motor in delta setup. Connect the three-phase adjustable AC source to the stator winding with the motor. Likewise connect the power analyzer for the circuit to measure the input voltage, current and electricity. The whole settings is displayed as number 2 . 5. 2 . 3 Set the dial in the three-phase adjustable AC source to zero position. Switch on the power supply and slowly but surely increase the voltage to the graded value intended for delta interconnection. Record the queue current, series voltage and two power reading W1 and W2. Also record the speed in the motor by using a tachometer. some. 2 . four Reduce the varying voltage to zero and switch off the strength supply. [pic]
Figure 2: No-Load Test out
4. three or more Blocked-Rotor Evaluation
4. 3. 1 Ease the anchoring screws on the foundation plate with the induction electric motor and maneuver it since close as is feasible to the POWER generator. Lock the base of the inauguration ? introduction motor with all the mechanism so that it cannot rotate. Tighten...