A cycloconverter converts AC voltage, such as the mains supply, to
another AC voltage.The amplitude and the frequency of input voltage
to a cycloconverter tend to be f
i
x
ed values, whereas both the amplitude
and the frequency of output voltage of a cycloconverter tend to be
variable. 
A typical application of a cycloconverter is to use it for controlling the
speed of an ac traction motor and most of these cycloconverters have a
high power output, of the order a few megawatts and SCRs are used in
these circuits.