| 摘要 |
PURPOSE:To prevent dew condensation under two-stage temperature control which does not require strictly the precision and also to prevent unnecessary power consumption by using a half-wave rectifier when the temperature in a machine rises by using two temperature switches. CONSTITUTION:The on temperature of the 1st and the 2nd thermostats 7 and 8 are set to about 5 deg.C and the dew condensation preventing heater 3 is powered on below said temperature. At this time, the 2nd thermostat 8 short-circuits the half-wave rectifier 9 and flows a full-wave AC current to the heater 3, which generates heat. Even when the room temperature rises after the start of room heating, the heater 3 is put in operation, so no dew is condensed. When the temperature in the machine rises up to 15 deg.C owing to the rise in the room temperature, the 2nd thermostat 8 turns off and the current flowing through the heater 3 passes through the 1st thermostat 7 and half-wave rectifier 9 to reduce the heating value of the heater 3 to about half. When the temperature in the machine attains to about 20 deg.C, the 1st temperature switch 7 is also turned off and no current flows to the heater 3, so that no heat is generated. |
