A hermetic motor-driven compressor is capable of decreasing both the resonance sound due to an oil feed pipe and the resonance sound due to a crankshaft generated when the oil feed pipe is rotated while being dipped in the refrigerating machine oil. In one aspect, an article comprises one or more machine-readable media storing instructions operable to cause one or more machines to perform operations. Sensing the velocity of the rotary element permits the determination of, for example, how much the rotary element slips on the discs. Access is granted in response to determining that all portions of the password have been answered correctly by the user. During compression the housing jacket is knocked at a frequency between 20 and 80 Hz to cause setting of the intumescent mat between the core and the jacket. The equipment consists of 2 bases, 6 cans, a ball and a bat.