A clock generator uses two PLL loops and a digital-to-analog converter to generate a variable output frequency from a single fixed-frequency reference clock. Significant degradation of air-conditioner and or heat pump components increases the operating cost by lowering the capacity of the system andor increasing the power consumption. The insulated wire includes the electric wire conductor and an insulating cover for covering an outer circumference of the electric wire conductor, and the exposed part is a part of the electric wire conductor which is exposed from a tip of the cover by a predetermined length.