Answer / siva kumar

UPS is a uninterrupted power supply, where as VFD is a variable frequency drive. VFD is used for controlling speed of the motors according to the below mentioned formula

speed(N)= 120f/p

f= frequency, p= no.of poles

poles are fixed at the design stage of the machine later we can't be modified so speed control is possible only controlling the frequency of the machine.

Answer / houssem

UPS converting incoming AC to DC through a rectifier and converts it back with an inverter with the same frequency

VFD converting incoming AC to DC through a rectifier and converts it back with an inverter with variable frequency according to operating point (Tm= V/F) of a motor

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