| 摘要 |
PURPOSE:To obtain a constitution, relating to a compressor used in a circulating type refrigerating machine for cooling an infrared sensor, etc., which reduces the pollution of He gas of ultrahigh purity injected into the compressor and ensures high reliability. CONSTITUTION:Three leads from the motor coil 9 in a housing 1 of a compressor are connected to hermetic terminals 13. The phase difference of the induced voltage is detected from the waveform of the induced voltage; after giving a phase shift by an electrical angle required and through subsequent logic conversion, a driving signal is obtained and a motor driver 14 for controlling driving current is connected. No sensor is used to detect the rotor position. Since, as a result, the motor driver can be provided outside the machine without the use of a rotor position-detecting sensor, the pollution of the He gas of ultrahigh purity contained in the machine, which is due to gases evolved from such a sensor or the like, can be reduced. Deterioration in the performance is prevented and the reliability is improved. |
