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Why are the Measured Values for Voltage, Current, and Power Unstable?

Check the "Sync Source" and zero cross filter (frequency filter) settings. For the WT3000, "Sync Source" setting is irrelevant if the data update rate is 250 ms, 500 ms, 1 s, or 2 s.

Sync Source Setting
In principle, if the AC signal is is not averaged over an interval synchronized with the cycle of the signal, a correct measurement cannot be obtained. For the applicable models listed above, the synchronous source determines the interval at which the cycle of the signal is detected and calculated. You should make a determination from the voltage and current waveforms as to whether to set the "Sync Source" to voltage or current.

Detection of the input waveform's period is made using a comparator (zero cross detector) referencing the center of the waveform's amplitude. Be sure to select a waveform for the "Sync Source" that: is nearly sinusoidal, has little harmonic distortion, and that has minimal jitter around the zero cross point (center of the waveform amplitude).

For example, with inverter motors and other such devices, current should be used since it is closer to sinusoidal than voltage which is a PWM waveform, but for commercial frequencies the voltage signal is often an ideal sine wave, so you should select voltage.

For inverters and other such devices, harmonic components are also included in the current, and sometimes the period cannot be detected accurately. In such cases, set the zero cross filter.

The zero cross filter (frequency filter) rejects components equal to or higher than the cutoff frequency, resulting in accurate period detection. The filter cutoff frequency for the WT210, 230, 1600, and PZ4000 is 500 Hz.

Checking the suitability of the "Sync Source" setting
For frequency measurement, check whether the fundamental wave of the item set to the sync source can be accurately measured.

相关产品和解决方案

PZ4000功率分析仪

PZ4000设计用于高频功率测量以及瞬时功率测量。此仪器的实时采集系统可执行按周期的功率测量。一到四个输入单元提供0.2%的基本精度,具备2MHz的带宽和5MS/秒的数字化速率。

功率分析仪 WT500

中等量程的WT500小巧且便于使用。使用其彩色TFT显示器可以观测数值和波形测量。提供1到3个输入单元,基本功率精度为0.1%,带宽为100kHz。

高性能功率分析仪 WT1800系列

高端WT1800是WT1600的升级产品,可应用于从节能到高负载应用在内的各种应用领域。WT1800拥有6单元输入能力,可提供最大的灵活性和5MHz带宽下0.1%的基本功率精度。

高精度功率分析仪 WT3000

WT3000高精度功率分析仪提供最高精度的测量。此产品已成为行业标准,用于变频器、电机驱动器、照明系统和电子镇流器、UPS系统、飞机电力系统、变压器测试和其它电力转换设备的研发。WT3000的基本功率精度达0.02%,带宽为1MHz。

数字功率分析仪

功率计或称瓦特计,可以测量产生、转换或消耗电能的设备各项特征,包括设备的各项参数,如:功率(瓦特)、功率因数、谐波和效率等等。

YOKOGAWA数字功率分析仪,性能优越、测量可靠,支持各种应用,非常值得拥有。尤其是YOKOGAWA WT300E功率计,已经在全球功率计市场份额上遥遥领先。

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