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The voltage is not equal in the 3 phases, see below. The impedance not equal, I think that are the power cables from transformer to VFDs GS

Hello. There is more oscillation just commutating diode, not all the time in the waveform. Maybe problems some any diode? GS

The output frequency vfd is fixed at 60Hz. GS

I believe in a resonance between inverter capacitor link dc and, cables AC supply voltage. GS

Hello iop95. Weg CFW11. Yes, I am sure. It is diode rectifier. GS

Fase A have oscillatory transients, and, Phases b c high frequency transients. The waveforms have 512 samples for circle around 30 khz. GS

Hello I made some measurement in 3 phase 60Hz 380V, in the input with 3 VFD 500CV same bus. Below waveforms voltage e current at max load, and resonance probability? maybe between capacitor DC Voltage bus x grid AC cables? The is 250 metes low voltage cables, betwenn suplly transformes and...

Hello DIgSILENT PowerFactory is the best of the all, but you have to be the best too. GS

Hello Marke. My initial question, was about the best supplier active harmonic filter in the world in your opinion and experience. I used passive harmonic filter with diesel generator (off grid) suppling vdf 300kw 6 pulses, and worked very well. I had problmes too with HF and Active harmonic...

Off grid GS

Hello In your experience and opinion, What is the best active harmonic filter in the world? GS

Hello Davidbeach Old audio amplifiers were called voltage amplifiers, and they use a transformer to reduce the voltage and increase the current. Mosfet amplifiers, also called current amplifiers, have no transformer, so a short on the output goes straight to the mosfet. I believe that...

Hello. Normaly for simplie relay 27, 59, 50F, 50N, 51F and 51N protections functions, I use old mono phase source (without amplifier). When I have complex relay with many protection functions, I rent omicron or similar relay tester. I Will try audio amplifier becouse is cheppear and its have...

Maybe I have to change the amplifier's internal output transformer, to the current input of the relay, which is almost a short circuit. The output of the audio amplifier is 2 ohms 250W, and relay current input is <0.02 ohms. GS

Hello. Anybody used audio power amplifier for protection relay test? GS

Hello. how to calc T'qo (quadrature axis short-circuit transient time constant) with: 𝑇′𝑑0 Direct axis open-circuit transient time constant 𝑠 2.460 𝑇′𝑑 Direct axis short-circuit transient timeconstant 𝑠 0.149 𝑇′′𝑑 Direct axis short-circuit subtransient time-constant 𝑠 0.020 𝑇𝑎 Armature...

Hello. Anybody could send me, any report about step and touch voltage measuring made in a substation? GS

Hello Metrel in usa have a good price, but it has low voltage open circuit, 50V, I can have problemas this it, when I have high impedance in remote rod, in this case red phase can is better, becouse there is 600v open circuit. Anybody have experience touch voltage mesurement? GS

Hello. Anybody help me please about step and touch voltage tester? Metrel, red phase, mitton or another instrument are the best for step and touch voltage measurement In medium and large substation? GS

Hi 200% of its rated, dont pickup instantaneous my low voltage Breaker, and there are high incident Energy. GS