| 摘要 |
PURPOSE:To reduce the number of parts of an electronic control circuit, to suppress the production cost to a low value and to gently make variable the temperature of a hot air flow by controlling the rotational speed of a blower for convection by means of a rotational speed control circuit for controlling the rotational speed of the blower for convection by the stepless variable operation of the blower for combustion. CONSTITUTION:The amplifying part 46A of a power supply circuit 46 of a blower for combustion continuously increase or decrease the outputs from a rotational speed control circuit 44 and a blower actuating circuit 45, and the voltage value is varied in a stepless manner. The power supply quantity of a blower 102 for combustion is continuously increased or decreased, and the blower 102 for combustion is continuously varied in a stepless manner. Further, similarly as the power supply circuit 46 of the blower for the convection, the amplification part 47A of a blower 303 for convection continuously increases or decreases the output voltages of circuits 44 and 45 to increase or decrease the resistance value of a varistor 47B and to continuously control the power supply quantity of a bridge 47C. Hence, the blower 303 for convection is continuously varied in a stepless manner. |
