| 摘要 |
PURPOSE:To automatically set an amount of the air for combustion coinciding with frequency, by a method wherein the number of revolutions is regulated according to decision of a frequency deciding means. CONSTITUTION:A frequency deciding circuit 20a, mounted in a microcomputer in a control circuit 21a, is set 60Hz when the voltage of an output terminal 38 is low and is set to 50Hz when it is high. Meanwhile, a switch tap is attached to a burner motor 13a, and the tap is adapted to be switched by means of a relay contact 39. Since a terminal 38 is low when the frequency of a power source is 60Hz, an inverter is increased in an output, and a transistor 42 is brought to an ON-state to close a relay contact 39. As a result, the motor 13a is switched to 60Hz, and even if a power source is 60Hz, the number of revolutions is the same as that in the case of 50Hz. This permits automatic setting of the air for combustion which coincides with frequency. |
