| 摘要 |
<p>The primary side of the burner control circuit, which has as its primary function the application of a lime voltage to the burner motor and igniter, includes: a triac switch for applying the line voltage to the burner motor and igniter in response to a first optical coupler; a circuit breaker switch for disconnecting the primary from the line voltage; and a light source for a second optical coupler. The secondary side of the burner control circuit,which is responsive to a thermostat, includes: a light sensitive element for detecting a flame at the burner; a light source for the first optical coupler; and a current responsive element which in combination with the circuit breaking switch in the primary functions as a circuit breaker. The first optical coupler responds to the thermostat to cause the triac switch to connect the motor and igniter to the line voltage and, if a flame is not sensed within a predetermined time by the light sensitive element, the circuit breaker will disconnect the motor from the line voltage. In addition, the second optical couplar serves as a safety device to disconnect the motor from the line voltage by means of the circuit breaker whenever the triac is in a shorted condition and the thermostat is not calling for heat.</p> |
