초록 ▼

A power control arrangement for controlling the power output of a resistive heating element of the type having a fast thermal response time and a highly variable resistance with temperature. The power control arrangement includes a plurality of operator selectable power settings and an electronic sw

A power control arrangement for controlling the power output of a resistive heating element of the type having a fast thermal response time and a highly variable resistance with temperature. The power control arrangement includes a plurality of operator selectable power settings and an electronic switching system responsive to operator selection of these settings to rapidly couple and decouple a power supply to the element. The switching action is selected to permit rapid heat up of the element without causing an unacceptable current to flow and to prevent excessive cooling of the element after it reaches operating temperatures during steady state operation.

대표청구항 ▼

A power control system for controlling power delivered to a heating element in response to selection of one of a plurality of power control settings including an OFF setting, said settings corresponding to different levels of power applied to said heating element, said element exhibiting a relativel

A power control system for controlling power delivered to a heating element in response to selection of one of a plurality of power control settings including an OFF setting, said settings corresponding to different levels of power applied to said heating element, said element exhibiting a relatively high resistance at high temperatures and a relatively low resistance at low temperatures, at least one of said power level settings operative to deliver power to said element, when at said relatively low temperature, which results in a current level which exceeds an acceptable limit, said power control system including transition detection means operating independently of current and voltage in said element for detecting a transition from said OFF setting to said one power setting, transient control means responsive to said detection means for delivering power to said element for a preselected time at a level lower than that associated with said one power setting, when said transition is detected, said lower power level being sufficiently low that current in the element does not exceed said acceptable limits, and steady state control means for controlling power to said element in accordance with said one setting after expiration of said preselected time.