60HZ vs 50HZ electrical sound comparison

This video is a ceiling fan operating at 120V 60HZ North American power. The second half is the same video clip but pitch adjusted to change the key from B2 to G2 sharp. (Or 100HZ instead of 120HZ). The reason for the double in frequency is because AC power will create a hum to exact X2 of the operating frequency due to magnetic fields induced in loose components vibrating. AC power basically pulses back and forth with a change rate of 50 or 60 times per second (depending on where in the world you live) and there is voltage on the “top” and “bottom” of that range and no voltage at the zero line. Thus, creating a sound frequency double that of the actual frequency of the grid power. Most of the world uses 50HZ AC at 220 or 230V and there are a few exceptions to this default. South Korea uses 220V at 60HZ, Japan at 100V 50/60HZ (east japan using 50HZ and west using 60) North America uses 120V 60HZ including Canada, the USA, Mexico (at 127V to compensate for voltage drop during high demand)