| 摘要 |
PURPOSE:To control the input of a motor for a furnace fan without lowering its agitating capability inside the furnace by changing the input voltage of the fan motor by which the furnace fan to stir the atmosphere of the furnace is turned in an interlocking manner with the temperature of the furnace. CONSTITUTION:The change in the temperature of an industrial furnace 1 is converted into a thermoelectromotive force by a thermocouple 2 which is in turn directed to a voltage regulator 4 as a control voltage (current) to alter the output voltage of the regulator 4, or the input voltage of a fan motor 6, by which the input of the motor 6 is controlled. Thus, when the temperature of the furnace 1 rises, the density of gas in the furnace 1 is correspondingly lowered, the load on the fan 5 is reduced, and load on the motor 6 is therefore lowered. Although the revolving speed of the motor 6 tends to increase, the thermoelectromotive force generated in the thermocouple 2 is also increased with rising temperature of the furnace to lower the output voltage of the regulator 4, or the input voltage of the motor 6. Thus, the motor 6 can be operated under such a condition that is kept almost constant with better power factor and efficiency. |
