GB1189119A - Dynamometer - Google Patents

Abstract

1,189,119. Rotary absorption dynamometer. NATIONAL RESEARCH DEVELOPMENT CORP. July 13, 1967 [July 13, 1966], No. 31558/66. Heading G1W. A hydraulic rotary absorption brake comprises a disc 1 mounted on a shaft 3 connected to a rotary power source and a casing 5 around the disc supplied with liquid at an adjustable rate and provided with an outlet 12 of predetermined size. The casing 5 is carried by a hollow shaft 7 in bearings 9 and angular deflection of the casing is restricted by torque measuring means which may comprise a torsion member. Water or oil is supplied through the shaft 7 and thrown outwards by the disc 1 to form an annulus 13 extending radially inward over the radially outward part of the disc 1 to a depth inversely proportional to the speed of the shaft 3 so that the torque absorbed at a given speed is proportional to the rate of supply of liquid at the inlet 11. Liquid overflows at 15 at the upper limit of torque for a particular speed and unstable conditions occur if the annulus 13 fails to cover the outer part of the disc 1. The range of torque that can be absorbed by the brake is increased in the embodiments of Figs. 2, 3, (not shown) by providing a series of discs of increasing diameter each in a separate compartment of the casing overflowing into the next at different radii. In the embodiment of Fig. 4 the casing 52 has four outlets 54 to 57 at different radial distances from the shaft 50, communicating through conduits 58 to 61 with valves 52 to 65 discharging into a trough 66. If all the valves are open, the number through which liquid is discharging is an indication of the immersion of the disc and hence of the proportion of full load. To operate the brake over a reduced power range, a smaller disc is used and one or more of the valves 62 to 65 are closed in sequence. The form of disc shown is suitable for high shaft speeds.