Droop Frequency, Droop Speed, Voltage Droop

Droop definition
The meaning of Droop is to weaken, fade, sag or lose energy.

What is frequency droop? What is speed droop?
Frequency droop or Speed Droop is the loss or decrease in frequency or speed as it go from no load to full load.

Percent Droop Frequency
Percent Droop Frequency is the ratio of the difference in no load and full load frequency to the full load frequency.

% Droop Frequency = [ (No Load Frequency - Full Load Frequency) / Full Load Frequency ] x 100%
 
Example:
Generator No Load Frequency = 63 Hz
Generator Full Load Frequency = 60 Hz

% Droop Frequency = [ (63 Hz - 60 Hz) / 60 Hz ] x 100%
% Droop Frequency = (3/60) x 100%
% Droop Frequency = 5% droop
 

Percent Droop Speed
Percent Droop Speed is the ratio of the difference in no load and full load speed to the full load speed.

% Droop Speed = [ (No Load Speed - Full Load Speed) / Full Load Speed ] x 100%
 
Example:
Motor No Load Speed = 1872 rpm
Motor Full Load Speed = 1800 rpm

% Droop Speed = [ (1872 rpm - 1800 rpm) / 1800 rpm ] x 100%
% Droop Speed = (72/1800) x 100%
% Droop Speed = 4% droop
 

What is droop voltage?
Voltage droop is the decrease or loss  in output voltage as it drives a load.