| 摘要 |
PURPOSE:To enable a stable combustion by a method wherein a combustion starting signal is fed out after the number of rotation of a fan is stabled in a control circuit or combustion unit such as a forced intake and discharging type gas boiler etc. CONSTITUTION:An operation switch is turned on and a motor (FM) is started to rotate at a high speed. When the motor (FM) is started to rotate, a frequency of a pulse generating circuit 3 is increased and capacitors C1 and C2 increase their potentials. In an amplifier OP1, a difference with an output from a speed setting circuit 4 is decreased down to the desired value, thereby the motor FM continues to rotate at the desired high rotation. In turn, in a combustion starting control circuit 7, the capacitor C2 is charged at a slower rate than that of the capacitor C1, the potential reaches to the desired value V4 after a time of t1 from the starting of operation, a positive (high) output is fed out from a comparator CP, this state is judged by the main control circuit 8 under the condition of OFF of a transistor Tr5 and then a combustion starting signal S is produced. Therefore, at this time, since the number of rotation of the fan motor FM is stabled, the burner shows a stable combustion under a proper volume of combustion air. |
