Amateur ExtraE4E05
What is used to suppress radio frequency interference from a line-driven AC motor?
B
Answer
Receivers, transmitters, and measurements
Type
A
A high-pass filter in series with the motor’s power leads
B
A brute-force AC-line filter in series with the motor’s power leads
C
A bypass capacitor in series with the motor’s field winding
D
A bypass choke in parallel with the motor’s field winding
Answer Notes
Line-driven AC motors with commutators and brushes (like those in vacuum cleaners or power tools) often produce severe electrical arcing. This generates broadband radio frequency interference (RFI) that conducts back along the AC power lines.
A 'brute-force' AC-line filter consists of heavy-duty inductors in series and capacitors in parallel. This creates a low-pass filter that safely passes the 60 Hz AC power to run the motor while severely attenuating the high-frequency RF noise trying to escape into the power grid.
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