First, high-speed motor test content
1, high speed motor efficiency test
High-speed motors have high power density, but the losses per unit volume are also large, especially the rotor's wind wear loss and eddy current loss are dozens of times that of general motors. The efficiency of the high-speed motor is obtained by the input power measurement of the motor (including voltage, current, power, power factor, etc.), output measurement (rotation speed, torque, power, etc.), excitation measurement, and the like. The high-speed motor efficiency test is used to analyze the related losses of high-speed motors. It is the key to the structural design of high-speed motors, improving mechanical characteristics, improving heat dissipation, and reducing losses.
2 high speed motor power supply system monitoring
2. The high-speed motor is generally powered by the inverter, which is very sensitive to the fundamental frequency and harmonic components of the power supply system. The voltage waveform outputted by the inverter is a PWM wave. In addition to the fundamental wave, it also contains a large number of high-order harmonics of an integer multiple of the carrier frequency, which will bring high-frequency additional loss to the high-speed motor, so the operation status and reliability monitoring of the power supply system It is very necessary.
Second, the key requirements of high-speed motor testing
1. In order to accurately obtain the efficiency of the motor, it must be ensured that the motor input electric power and the motor output shaft power are strictly measured synchronously.
2, must meet the measurement needs of the fundamental wave voltage, fundamental frequency, harmonic analysis, etc. of the inverter output PWM wave.
3. The test system consisting of sensors and test instruments must have an overall accuracy of 0.2.
4. Since the power factor of the high-speed motor is less than 0.2 when the no-load test is performed, the angular difference index of the test system must meet the requirements of power measurement accuracy under low power factor conditions.
5, high-speed motor test site general electromagnetic environment is complex, the test system must have strong anti-electromagnetic interference capability.
Third, high-speed motor test solutions
This test system uses WP4000 variable frequency power analyzer developed by Galaxy Electric. The power unit uses SP series variable frequency power sensor to measure electrical parameters. The DM4022 frequency test substation collects the signal of torque speed sensor. SP frequency conversion power sensor and DM4022 pass optical fiber and WP4000 frequency conversion. The power analyzer is connected. A block diagram of the high-speed motor test system is shown in Figure 1.
WP4000 variable frequency power analyzer and SP variable frequency power sensor adopt front-end digital technology, which completely avoids the attenuation and interference of the transmission link itself in complex electromagnetic environment, and cuts off the most important interference propagation path of the sensor, and enhances the electromagnetic of the sensor and system. Compatible performance.
Each power unit of WP4000 variable frequency power analyzer has independent synchronization source. The sampling frequency of 200KHz collects all parameters synchronously, ensuring synchronous measurement of motor input and output power, and has an effective bandwidth of 100KHz to meet the harmonic analysis requirements of PWM wave.
SP series variable frequency power sensor (type B), voltage and current accuracy is 0.1% of reading, in the range of power factor 0.05~1, maintaining power accuracy is 0.2% of reading, meeting the needs of high-speed motor testing.