What is the wave-form factor (w) for a three-phase six-pulse x-ray generator?

What is the wave-form factor (w) for a three-phase six-pulse x-ray generator?

• A. 1.0
• B. 1.35
• C. 1.8
• D. 2.0

Answer: (B)

The main idea is how much the actual voltage waveform across the x-ray tube deviates from a steady DC level. The waveform factor is the ratio of the rms voltage to the average voltage of that waveform. In a three-phase six-pulse x-ray generator, the output is a six-pulse rectified waveform. It isn’t perfectly flat, but it has much smaller ripple than a single-phase supply. The RMS value is raised by the presence of the pulsed peaks, while the average level sits lower, so their ratio ends up around 1.35. That’s why the waveform factor for this setup is about 1.35. The other numbers would correspond to noticeably different waveform shapes or ripple levels, which aren’t characteristic of a typical six-pulse three-phase output.

The main idea is how much the actual voltage waveform across the x-ray tube deviates from a steady DC level. The waveform factor is the ratio of the rms voltage to the average voltage of that waveform. In a three-phase six-pulse x-ray generator, the output is a six-pulse rectified waveform. It isn’t perfectly flat, but it has much smaller ripple than a single-phase supply. The RMS value is raised by the presence of the pulsed peaks, while the average level sits lower, so their ratio ends up around 1.35. That’s why the waveform factor for this setup is about 1.35. The other numbers would correspond to noticeably different waveform shapes or ripple levels, which aren’t characteristic of a typical six-pulse three-phase output.