Speed Drop Following Load Increase Formula

Equation for calculate speed drop following load increase is,

n_t/n (in USCS) = [1 - 1,620,000T_tP_t / WR²n² (1 - h/H)^3/2]^1/2

n_t/n (in SI) = [1 - 365,000T_tP_t / GD²n² (1 - h/H)^3/2]^1/2

where,
n_t - is the speed, at the end of time T_t
T_t - the time interval
P_t - reduction in load
WR² is the product of the revolving parts weight, lb, and the square of their radius of gyration, ft
n - is the speed
h is the head rise caused by the retardation of the flow
H is the net effective head before the load change
GD² is the product of the revolving parts weight, and the square of their diameter of gyration, m.