Noise problems of appliance drain pumps

The drain pump is one of the significant noise sources of washing machine and dishwasher appliances. The pump can generate vibrations, particularly when operated under load. This vibrational energy is converted into radiated sound energy through the large surface of the chassis, kickplate and sidewalls of the cabinet. Structure-borne noise of the pumps is dominant around 100 Hz. The pulsating suction noise of the drain pumps is one of the reasons for airborne noise in the appliances. Suction noise is caused by sucking air when most of the water has been drained. The rest of the sources of the airborne noises are the fan blade and (partially) the impeller blades.