How mains frequency gets its name

[japlytic]

I discovered that mains frequency is actually twice the rated frequency e.g. a so-called "50Hz" region actually has 100Hz mains, comprising of 50 positive sine pulses and 50 negative sine pulses for a total of 100 sine pulses per second.
This so-called "mains frequency" got me confused me at one time... does the same rule apply to 400Hz mains?
Also, I've seen vintage power transformers rated for 1kHz AC and even 2kHz AC supplies... again, does the same rule apply?

[stj]

Re: How mains frequency gets its name

a full sine ~ wave goes from 0 to positive peak, then down to negative peak, then back to 0.
so it's 50Hz - not 100Hz

~

[CapLeaker]

Re: How mains frequency gets its name

what stj said. The sine is complete from zero to positive peak, zero, negative peak and back to zero. The speed is how often id does that per second. 50hz means it does this 50 times per second.

If you rectify 50hz with a full wave rectifier you get a 100 DC pulses per second, since the diode flips the negative part of the sine wave to the positive one.

[budm]

Re: How mains frequency gets its name

The ripple frequency of the full-wave rectifier output will be double of the main frequency.
http://web.physics.ucsb.edu/~lecture...er/Pages/64.58

[japlytic]

Re: How mains frequency gets its name

If you rectify 50hz with a full wave rectifier you get a 100 DC pulses per second, since the diode flips the negative part of the sine wave to the positive one.

This is how general purpose electrolytic capacitors get their 120Hz frequency rating for a given ripple current rating as per the datasheet.