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Single Phase Measurements.

At first glance, making single phase measurements should be simple. Every wall socket is a single ac source. Every household appliance connected to the mains draws on this single phase ac current.

If the load is a simple resistive load such as a heater that is on continuously, then making measurements on that current is straightforward. However, more and more equipment now draws very complex current from the ac supply, so measurement becomes more challenging.

Sometimes the current is drawn in bursts, sometimes it can be highly distorted and have a high crest factor. Sometimes measurements need to be made in the presence of common mode. Making accurate measurements in these situations requires care.

To learn more about factors to consider when making accurate single phase measurements, please contact us for a copy of Voltech's 'Back to Basics: AC Theory's handbook.'

Single phase measurements and standby power

Many household appliances plugged into the mains will still draw a small current when 'switched off'. This current draw is known as standby power. Measuring standby power is an even more complex type of single phase measurement. The current is often drawn in bursts as needed by the equipment, and the amount of current is extremely small when compared to normal current drawn when the equipment is in use. Making standby power measurements accurately requires specialized power analyzers.

To learn more about making standby power measurements please contact us and we'll send you a copy of Voltech's handbook of testing standby power.

Single phase measurements and harmonics.

An even more specialist form of single phase measurement is needed when measuring harmonics. Equipment such as a photocopier or xerox machine does not draw a continuous current. It will draw power intermittently making the measurement of that current challenging.

Most countries are now tightening the standards for measuring harmonics. The IEC defines the benchmark standards that are being adopted around the world. IEC standard 61000 discusses the measurement of harmonics, as well as flicker and inter-harmonics. On our website you can find more information on harmonics and flicker measurements, as well as links to the standards.

What's involved in making accurate measurements?

The accurate measurement of electrical power has never been more important than it is today. Voltech's PM1000+ single-phase power analyzer combines bench instrument accuracy with sophisticated energy consumption features and low-power standby measurements. It also simplifies the checking of equipment for harmonics and flicker. In addition, The PM1000+ can accurately make complex single-phase measurements of the kind discussed above.

• accurate up to crest factors of 20 - no compromise specification on distorted waveforms.
• built with low power standby in mind - no special accessories or channels required.
• Harmonics to IEC61000-3-2 (pre-compliance)
• Flicker to IEC61000-3-3 (pre-compliance)
• the most cost effective solution on the market.