Lab #5 Lab due date is 3ph Non-Linear Load Harmonics PURPOSE: The purpose of this lab exercise is to gain an understanding of the harmonic distortion associated with three phase variable frequency drives (VFDs), and the impact that input circuit impedance has on the harmonic distortion. in week 1 ward 83ow EQUIPMENT REQUIREMENTS: PowerFlex 1HP VFD 1HP motor/dyne Line Reactor Fluke 43B with V probes & 1x CAT Lab Procedures: (NOTE: ALL MEASUREMENTS TAKEN AT INPUT SIDE OF VFD) You will use the Fluke 43B to take harmonic measurements, waveforms and three phase power measurements. Check instrument setup before proceeding. Use %f (not %r). Check probe settings also. Test 1: Connect three phase AC power to VFD and electric motor. Connect voltage probes to voltage source terminals. Connect current clamps to VFD input circuit. Energize motor. Apply full load to motor. Consider Full Load to be 830 Watts at VFD INPUT. View and capture: current waveform, current spectrum, voltage waveform, voltage spectrum. Using FLUKE 43B in 3ph power mode, measure and capture 3-phse input kW, KVA, PF. Circuit 1 0 3-phase Transformer 208V VFD Motor Report Procedures: 1) Tabulate all of your numerical data in a chart. Test Circuit Test 1 Circuit 1 VFD 100% Load current Voltage Test 2 Circuit 2 VFD + line reactor 100% load Current Voltage Test 3 Circuit 2 VFD + line reactor 50% load Current Voltage Load Condition % THD |(1) rms I(3) rms |(5) rms |(7)rms |(9)rms |(11)rms |(13)rms |(15)rms I (Total RMS) kW KVA PF(total) 2) Plot the harmonic current spectra for all three test conditions on a single Excel graph. 3) Draw the harmonics triangles for each of the tests 1-3. 4) What happens to the magnitude of harmonic current (amperes, not %) as load is reduced? 5) What happens to the %THD-i as load is reduced? 6) How does PF(Total) differ for VFD with reactor, vs. without reactor? Interpret the data and include written explanations with each chart, graph and set of data. Page 32 REFERENCE: To set load when operating motor from VFD, measure power at input to drive. (1 HP x 746 W/HP)/ 0.956 (eff) = 780 watts 2 Total RMS Harmonic Current = Ihrms V1, +15° +1, +1, +1° +1,3 + Total RMS Current = Irms = 11,? + 1; +1, +1, +1, + ° +° , +1,32 THD = Total Harmonic Distortion (-i = current; -v = voltage) % THD-i = RMS Harmonic Current (Ihrms) RMS Fundamental current (11) 2 VI; +1+1, +1,' +11° +13 1 -- 100% O PF(total) = PF PF (displacement) PF (distortion) Test 2: Add line reactor at the input of VFD; motor at full load. Energize motor. Apply full load to motor. (Consider Full Load to be 830 Watts at VFD INPUT). View and capture the following: current waveform, current spectrum, voltage waveform, voltage spectrum. Using FLUKE 43B in 3ph power mode, measure and capture 3-phase input kW, KVA, PF. Circuit 2 0 3-phase Transformer 208V AC Line Reactor VED Motor Test 3: Add line reactor at the input of VFD; motor at 50% load. Same setup as 2, except reduce load to 50%. (Consider Full Load to be 830 Watts at VFD INPUT). View (and capture) current and voltage waveforms and harmonic spectra. Using FLUKE 43B in 3ph power mode, measure and capture 3-phase input amps, kW, KVA, PF. Data Tabulation: Test Load Condition Test 1 (Ckt 1) VFD 100% Load current Voltage Test 2 (Ckt 2) VFD + line reactor 100% load Current Voltage Test 3 (Ckt 2) VFD + line reactor 50% load Current Voltage % THD |(1) rms |(3) rms |(5) rms |(7)rms |(9)rms |(11)rms |(13)rms |(15)rms I(Total RMS) kW KVA PF(total)
Purchase answer to see full attachment