... , have the following relationship between the shaft power, pressure, speed and flow: Flow and speed time proportional to the square; proportional to the square ... = K3 * N3 N-speed Q-flow pump outlet pressure P-PW-shaft power K1, K2, and K3-constant as shown in the ... PW, rated outlet pressure is P, and the rated flow is Q.Then produce the rated flow, shaft power: PW = K * P * Q ...