Three Phase AC generators (1 Viewer)

[HyperComplexxx]

How would you represent voltage output on a graph?
Do you add the three phases together or what

 

[jamesfirst]

It's in the Jacaranda textbook

They have draw 3 sine graphs with different periods and superimposed it I think.

 

[HyperComplexxx]

i see
also what does it mean when it says DC output can be made smoother by adding more coils to armature

 

[Fizzy_Cyst]

i see
also what does it mean when it says DC output can be made smoother by adding more coils to armature

The output of a DC generator is not a true DC signal, it is merely a full-wave rectified AC signal (i.e., absolute value of an AC graph)



Real DC generators generally have 3 coils, 120degrees out of phase with eachother and each coil hooked up to a part of a multi-part commutator and the section of the commutator connected to the coil which is most parallel to the field is in contact with the brushes. (diagram below is of a 2 coil DC generator)



This ensures the output voltage/current is always close to maximum and produces what is called a "ripple" voltage (diagram shows output from a 2-coil DC generator) -- the output EMF is the bold black line



This "ripple" voltage is smoother than from a single coil DC generator corresponds much more to a true DC signal (straight horizontal line on a Voltage vs time graph), even more so if a capacitor is added to smooth the voltage further.
Also, the more coils you put in the closer this "ripple" voltage gets to a true DC signal.

 

[HyperComplexxx]

wow thanks, cleared it up a lot

 

[Fizzy_Cyst]

awesome!

Thanks for saying thanks! =)