General-purpose power-quality monitor for on-site testing and troubleshooting

November 26, 2015 // By Graham Prophet
The Yokogawa CW500 power quality monitor, a general-purpose unit for field and on-site testing and troubleshooting, is the latest addition to the company's range of power measuring instruments.

Featuring a range of clamp-on current probes, built-in data logging and measurements conforming to the IEC 6100-4-30 Class S standard, the CW500 is a multi-function instrument designed to aid the inspection and maintenance of power quality in factories, commercial or public facilities. In particular, it will detect, measure and record events such as voltage swells, sags, dips or interruptions, inrush currents, harmonics distortion and flicker which can have an adverse effect on equipment operation or energy efficiency.

The 4-channel instrument can measure multiple power lines in configurations from single-phase/2-wire up to 3-phase/4-wire, and will simultaneously measure AC voltage input on three channels, current input on four channels and DC voltage input on two channels. Parameters measured include the instantaneous, average and maximum/minimum values of voltage, current, DC input voltage, power, power factor and phase angle, along with phase advanced capacitance calculation.

All measurements are displayed on the built-in colour screen in list, waveform, or trend formats with direct keypad control. The integration values of active, reactive and apparent energy are each displayed by consumption and generation, and demand power value can be monitored continually via graphical screens of power consumption compared to the targeted demand power value.

Intermittent anomalies such as voltage swell, voltage dip, voltage interruption, transient overvoltage and inrush current are each recorded as events and marked on occurrence waveforms, with the type of fault listed for each event. Ongoing or continuous faults such as harmonics, flicker and voltage or current imbalance rates are recorded with waveforms displayed as required.

The CW500 operates over an input AC voltage range from 6 to 1000V and a DC voltage range from 100 mV to 10V. The current ranges are from 2A (for leakage current only) to 3000A, with intermediate ranges of 50A, 100A, 200A, 500A and 1000A depending on which dedicated clamp-on current probe is used. Accuracy for power measurements is 0.3% of reading.