JP2732694B

PURPOSE:To enable a cracked gas generated within a case to be automatically detected at an early stage by equipping a gas take-out means, its drive control means, and a semiconductor-type gas sensor. CONSTITUTION:By driving a gas flow control valve 7, for example, once a day, gas is taken out of a tank 1 and is detected by a semiconductor type gas sensor 4 of a detection device 9. A cracked gas is generated within a tank due to discharge or excessive heating of a winding 4. In this case, the gas flow valve 7 is driven and gas is taken out within one day, the cracked gas is detected by the sensor 14, and concentration of the cracked gas is shown at a display device 10. With this configuration, the cracked gas generated within the case due to abnormality of the equipment main body can be automatically detected at an early stage.