Abstract: The present invention relates to a central vacuum power unit comprising in combination a canister, a chamber for collecting debris, a first plate, a second plate, a third plate, a duct means, a motor-fan assembly, a filtering means, a first baffle means, means for generating a flow of cooling air for an electric motor, and means for reducing the emission of noise outside the canister. This central vacuum power unit is characterized in that a portion of said piping passes across a further opening is provided in the plate which is provided with the seat of resilient vibration dampening material and is receiving the motor-fan assembly, in that said portion of piping has a vertical axis substantially parallel to the axis of the intake of the vacuum fan, so that any deformation of the seat due to the vacuum existing underneath the motor-fan assembly will allow the piping to slide freely in said further opening without solid contact with said plate.

Abstract: A silencer to be mounted on the air intake of a cooling fan of an electric motor in a vacuum cleaning system. The silencer comprises a cylindrical housing closed at one end and opened at the other end. The housing is provided with perforations around its periphery adjacent the closed end. A sleeve made of sound absorbing material lines the inside of the housing without obstructing the perforations.