Industrial Engineer · phase 13 of 16
Sine-Wave Filter
Output filter that converts the PWM waveform toward a sinusoidal motor voltage.
The Explain card
- Plain English
- A sine wave filter is a larger inductor and capacitor network that smooths the PWM output into something close to a true sine wave. The motor sees clean power, as if it were on the line.
- Example
- A submersible pump 800 meters down a well runs through a sine filter. The cable never sees PWM edges, and the motor is a standard unit rather than an inverter duty one.
- Why it matters
- It solves reflected waves, cable ringing, motor noise and most insulation stress in one piece of equipment. It is large, hot, and it limits how high the output frequency can go, so it is a considered purchase.
- Hook
- Make the drive look like the utility.
Where it sits in the deck
Phase 13: VFD Power Quality, Wiring, and Motor Protection
Harmonics, reflected waves, shielded cable and bearing currents: the side effects a drive inflicts on everything around it.
