10. Power factor and cos IEC / IEEE Definition Power Factor = Watts Volts x Amps PF = 0.65 Cos Cos Angle between fundamental (1st harmonic) voltage and current. Voltage Current Harmonics Fundamental (1st Harmonic) 3rd Harmonic Total Current
15. Multi-phase measurements Power Station 3-phase and 1-phase loads 415V phase to phase 230V phase to neutral Distribution Transformer Industrial, Office and Domestic Loads N For balanced loads (same current in each phase), neutral current = 0 Small neutral conductor
16. Triplen harmonics Definition: ‘Odd Harmonics divisible by three’. E.g. 3, 9, 15, 21, 27, 33… Why are they so important to the three phase power industry? Third harmonics of each phase IN PHASE with each other.
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18. Multi-phase measurements 2 Wattmeter vs. 3 Wattmeter connections #1 3 Wattmeter #2 2 Wattmeter 2 wattmeter connection provides all the information required for 3-wire measurements. V1 V2 V3 V1 ph-ph V2 ph-ph
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20. AC motors Input 2 Wattmeter or 3 Wattmeter method. Output Torque and Speed Mechanical Power V I Electrical to Mechanical Efficiency
21. PWM motor drives Distorted AC Input DC Bus PWM Output Torque & Speed xxx NM & Rev / Min
22. PWM voltage spectrum Fundamental (E.g. 40 Hz) Switching or carrier (E.g. 10, 000 Hz) Total Power = Fundamental + Harmonics (f) + Carrier + Harmonics(c) + Noise
23. PWM mode Filters 5Hz to 1kHz Low Frequency Measurements Frequency High Frequency Measurements Sync Fundamental Data Frequency Total W, V, A... Measurements to full 1MHz bandwidth
28. IEC Standards. Flicker. The IEC aim to limit level of voltage fluctuations that equipment may cause to AC power lines. Standards exist for up to 75A. Change in the load current will cause change in voltage across the load. That change in voltage causes a squared change in lamp output intensity. The perception of ‘flicker’ is dependant on the response of the lamp, our eyes and our brain.