Counterweight for reduced height sealed compressor

A sealed compressor 20, such as a scroll compressor, has a pump unit 22,24 driven via a shaft 26 by a motor 28, with a counterweight 34 mounted between the motor and the pump on the shaft. The counterweight 34 has a neck portion 36 mounted on the shaft, and a relatively thin portion 38 which extends axially from the neck 36 towards the pump unit, utilising the limited space in the reduced height compressor whilst providing a centre of gravity towards the pump unit. The profile of the counterweight 34 may be formed with a backdraft (52, Fig 3B) to resist lubricant from climbing up the axially extending portion 38, or it may be formed with an air foil angle (50,54,56, Fig 4) to control the flow of fluids within the sealed compressor.