Motor testing bench

Motor testing bench

In order to meet the requirements of market development and cooperate with motor manufacturers, our company has developedMotor testing benchThe motor test bench can perform various tests on motors, including no-load power, three-phase voltage, no-load current, active power, reactive power, speed, temperature rise, vibration, and motor short circuit testing.

2： Equipment performance

This equipment is assembled using national standard products, with a simple structure and reliable performance. The test bench output adopts dual protection (overcurrent protection and leakage protection), effectively protecting the safety of personnel and equipment.

Three:Main technical parameters

1. Working voltage three-phase four wire380V 50HZ

2. Rated power measurement7.5KVA

3. Measurement range of over/under test: three-phase0500V, Level 0.5

4. Voltage withstand test measurement rangeAC05000V, Level 0.5

5. Capable of measuring three-phase current and three-phase voltage of motors

6. Capable of measuring the active and reactive power of the motor

7. Capable of testing motor speed

4： Usage and Instructions

1. First, place the test bench and the tested motor steadily, and connect the 380V three-phase four wire power supply to the L1, L2, L3, and N terminals of the test bench. Test bench three-phase 0-500V outputUA. Connect the UB and UC terminals to the U, V, and W terminals of the tested motor. The clamp is installed on the shaft of the motor, and the speed sensor needs to be connected to the test bench and fixed on the base. The base needs to be placed at a suitable distance from the motor.All devices should be securely and reliably grounded.All the above wiring must be tight and secure!

2. Operators should wear insulated equipment and ensure insulation safety. The testing site must be spacious, dry, with a distance of about 3 meters between the testing platform and the tested motor,

3. Before the first use, it is important to test whether the voltage rise and fall meet the requirements. Specifically, when turning the knob to increase the voltage, the reading on the voltmeter should rise. If not, the motor wiring terminals U, V, and W should be swapped;

4. After confirming that all connecting wires are correct, connect the power supply to the test bench,

5. Is the "zero" indicator light on the console panel "on"? If not, turn the knob counterclockwise until the "zero" light is on, start the control cabinet and close it. Turn the knob clockwise and pay attention to the "three-phase voltmeter". When the voltage rises to about 30% -55% of the rated voltage of the motor, press the "output" button to start the motor and raise the voltage to the "rated" voltage of the motor until it reaches the rated "current" of the motor. At this time, the three-phase ammeter, three-phase voltmeter, tachometer, and three-phase multifunction meter display the actual parameters of the motor. (Please refer to the user manual for the three-phase multifunction meter for instructions on how to use it.)

6. AC motor no-load test:

⑴: Purpose of the experiment; The purpose of the no-load test conducted by the repair unit is to check the assembly quality, iron core quality, and whether the vibration and noise of the motor are normal after repair; In addition, it is to measure the no-load loss, no-load current size, and their balance; Simultaneously measure active power, reactive power, iron loss, mechanical loss, and calculate no-load characteristics.

⑵ Connect the motor and test bench, turn on the power switch on the panel, set the current selection to the corresponding position, adjust the voltage regulator clockwise, and when the power supply voltage rises to 1/2 of the rated voltage of the motor, press the "output" button on the panel to start the motor running. The ammeter and power meter should display, and then increase the voltage to the rated voltage of the motor. Generally, idle for 20-60 minutes according to the power of the motor. If the motor capacity is large, it can rotate for more time;

After the motor is powered on, check the operation of the instrument and motor. Only when everything is normal can it be raised to the rated voltage value for testing. During the experiment, it is necessary to record the voltage Uo, current I0, power P0, and speed of each phase. At the same time, check whether the no-load current I0 is balanced in all three phases and whether its magnitude is correct

Within the normal range, it is required that the difference between the no-load current of any phase and the average value shall not exceed 10% of the average value, and the no-load current and no-load loss shall not exceed 10% compared with the factory test.

7. Locking test:

⑴ Purpose of the experiment. Measure the locked rotor current, locked rotor torque, and locked rotor loss, and check the motor starting performance; Check for motor faults, such as winding faults, misaligned iron core installation, and iron core quality faults.

⑵ Use tools or other methods to hold the motor in place, set the output of the voltage regulator to 0, press the "close" button on the panel, the "work light" will turn on, and then rotate the knob clockwise until the current value approaches the rated current value. The reference selection test voltage values are as follows:

If conditions permit, for motors of 100KVA and below, it is allowed to operate within 4 Conduct the test at 5 times the rated current; For 100-300KVA motors, the maximum test current is 2-4 times; The maximum current for the locked rotor test of motors of 300 and above shall not be less than 1 5-2 times the rated current. During the experiment, at least 4 reading points should be measured, and the power frequency and power stability are required.

⑷ Analysis of experimental results

A small blocking current is caused by an increase in rotor resistance and reactance. Like.

①Increase in air gap(Turning the rotor);

②The center assembly of the stator and rotor is not aligned;

③Welding detachment (soldering);

④ The cast aluminum rotor has defects.

The reason for excessive stalling current is due to a decrease in rotor reactance, such as:

①The number of turns in the coil is small;

②Small coil size;

③Excessive air gap;

④The stator and rotor iron cores are not aligned.

8Withstand Voltage Test

Connect the high-voltage lineThe "red line" is connected from the 5KV high-voltage output head of the test bench, and the motor terminal is clamped with a clip. The "black line" grounding wire is connected from the grounding terminal to the motor housing. The power switch is turned on, and the voltage regulator is set to "0". The "zero adjustment" indicator light is on. Press the "close" button to adjust the voltage regulator to the "rated" voltage, set the test time, turn on the time reset button, start timing, reach the set time, automatically open the circuit, and adjust the voltage regulator counterclockwise to the zero position.