The waveform changes rapidly during the start-up and stop of a motor . The usual practice for start-up and stop testing is to use an oscilloscope. However, oscilloscopes have low accuracy and cannot accurately measure and calculate data. The following content will propose a new solution.
I. Current Status of Motor Start-up Testing
Electric motors are ubiquitous in our lives, and motor technology is crucial to our future development. Testing motor performance is of great significance to motor developers. During normal operation, motors are typically controlled within their high-efficiency range, resulting in relatively stable operation. Therefore, traditional motor testing focuses solely on steady-state testing. However, with the continuous improvement of motor control precision and the increasing complexity of motor application environments, more and more people are paying attention to rapid, sudden signals such as motor start-stop states and transient responses. Traditionally, measuring these rapid, sudden signals requires high-performance oscilloscopes or waveform recorders. However, oscilloscopes have low accuracy and limited computing power, while waveform recorders, although offering guaranteed accuracy and computing power, are extremely expensive, thus rarely used in practice. Power analyzers are essential instruments for motor testing; if they could be used to perform rapid transient tests on motors, it would be the most effective and cost-efficient solution.
II. Challenges in testing motor start-stop using a power analyzer
Since using a power analyzer is the optimal solution for motor start-stop testing, why didn't power analyzer manufacturers initially include motor start-stop and transient testing functions ? There are reasons for this, and we will compare a power analyzer with an oscilloscope.
Oscilloscopes have a high sampling rate, usually measured in GSa/s, but their ADC bits are only 8 bits, so the accuracy is insufficient. More importantly, oscilloscopes have dead zones when measuring waveforms, meaning the waveform will be lost. If the oscilloscope enters rolling mode (to ensure that the waveform is not lost), the sampling rate will be greatly reduced, further reducing the accuracy.
Power analyzers require high precision, with ADCs at least 16-bit or even 18-bit. Unlike oscilloscopes, power analyzers cannot tolerate dead zones; all waveforms and data must be acquired and analyzed to ensure accurate results. Because of the higher ADC bit depth and the need for real-time data processing, the computational power requirements for power analyzers far exceed those of oscilloscopes. Currently, most power analyzers lack sufficient processing power to record waveforms while simultaneously processing the data.
ZLG Power Technology - Zhiyuan Electronics' PA series power analyzers benefit from their powerful hardware architecture and creatively implement edge computing on the board, greatly reducing the computing task of the host. Therefore, they can record waveforms in addition to data calculation, and further realize fast and transient testing of motors.
III. Methods for Waveform Recording in Power Analyzers
There are several methods for waveform recording using PA series power analyzers; two commonly used methods are introduced here.
1. First method: Direct waveform recording and display by the instrument.
The PA power analyzer has a "Routine Analysis" function in its menu, as shown in the figure below.
After entering the "Routine Analysis" function, click the "Measurement" button on the interface. At this time, the waveform on the instrument interface will stop refreshing. Then, select the waveform frame you want to view through the menu, and the recorded waveform will be displayed on the screen. You can zoom in and out of the waveform or perform measurement and analysis on the waveform, just like operating an oscilloscope.
2. The second method involves recording waveform data with an instrument and then analyzing it using software.
On the PA series power analyzer, clicking the "store" button will enter the storage settings menu. In the list of stored data items, select the item corresponding to the waveform data.
After setting up, click the "Start" button to save the data. Once saving is complete, click "Stop" or "Reset" to save the settings. The PA series power analyzer has a built-in 60GB solid-state drive, which can meet the needs of storing waveforms for extended periods. After data storage, the data can be exported to a PC in various ways, and then processed using standard host computer software. This way, you don't have to worry about rushing the data analysis.
ZLG Ligong Technology - Zhiyuan Electronics' new series of power analyzers has achieved a waveform refresh rate of 1ms, which can not only record waveforms, but also easily perform transient tests on motors. The testing of transient changes in motors will be discussed further later.
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