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As you can imagine with a large proportion of engineering activities, choosing the incorrect tool may have serious implications on the results of your measurements. The information contained below is to help visitors make a more informed decision on a power analyser which is most appropriate for their requirements.

The method used depends on whether DC or AC power is being calculated. AC power is further broken down into three types, see below:

**DC power**: DC power is calculated by multiplying voltage (Volts) by current (Amps). The resultant power is measured in Watts (W). This is based on Ohm's law, and is true where the flow of current is always in the same direction.

**AC power**: In an alternating current (AC) circuit consisting of a source and a load, both the current and voltage are sinusoidal at the same frequency. AC power consists of active power, reactive power and apparent power.

- Active power: Active power AKA real power is the amount of power that is actually consumed in an AC circuit. Active power is the instantaneous voltage multiplied by current averaged over the fundamental period. Thus to calculate active power, the fundamental frequency must also be measured.
- Reactive power: The reactive power (kVAR) establishes the magnetic field in the motor that enables it to operate. It represents the amount of power that continuously bounces back and forth between the source and load meaning the power which cannot be used for effective work in an AC circuit or system. It is the difference between active and apparent power.
- Apparent power: Apparent power is the vector sum of active and reactive power, and is the product of the RMS values of voltage and current over the fundamental period.

In an electric power system, a harmonic of a voltage or current waveform is a sinusoidal wave whose frequency is an integer multiple of the fundamental frequency. Harmonic frequencies are produced by the action of non-linear loads such as rectifiers, discharge lighting or saturated electric machines.

The effects of harmonics on electric systems are adverse, with effects including increased heating due to iron and copper losses, and higher audible noise emission.

As well as calculating electrical power on 1 or more phases, mechanical power and energy, advanced power analysis using the following analysis techniques is also available with the **Dewetron power analyzer** line:

- Inverter, electrical machine (motor) and total efficiency calculation
- Speed-torque efficiency mapping
- Harmonics and FFT data
- DQ analysis (Park-Clarke transformation)
- Drive cycle power and energy measurement, e.g. WLTP
- Synchronised vibration and sound measurement
- Digital interface – CAN, EtherCAT, Ethernet.