The Char-Lynn 10,000 series motor with 40.6 in3/rev displacement was chosen for an example. (Notice that this displacement is approximately 10 times the displacement of the high-speed motors previously studied.) This motor has a maximum speed of 254 rpm for continuous operation. Maximum pressure is 3000 psi. Efficiencies were calculated for an input flow of 36 GPM, the same flow used for the high-speed motor comparison.
Volumetric efficiency for this motor was higher than for the gear motor, ranging from 98% at 500 psi to 93.3% of 2500 psi (Fig. 5.8). Overall efficiency increased from 79.5% at 500 psi to 86% at 1000 psi and remained nearly constant for higher pressures. The speed of this motor is 201 rpm at a pressure drop of ?P = 500 psi and 191 rpm at 2500 psi, a drop of only 5%.
