| 摘要 |
A solid state load protection system whereby the current supplied to a load is monitored enabling a test feature to be used. A current sensing function is utilized so as to produce an output current which is proportional to the current in an electrical circuit. Attached to the current sensing function is a load resistor module which converts the current produced by the current sensing function to a voltage which is also proportional to the current utilized by a load. Attached to the module is an overcurrent and timing function and an output function. The overcurrent and timing function monitors the level of voltage from the load resistor module initiating a timeout sequence when the voltage across the load resistor function, which is proportional to the current utilized by the load exceeds a predetermined level for a predetermined period of time thereby initiating a trip signal to the output function which deenergizes the motor by disconnecting it from its source of power. Upon the removal of the load resistor module and all other modules the input impedance of the overcurrent and timing function becomes very high allowing the test function to simulate an overcurrent condition in a load by causing a higher voltage to appear at the overcurrent and timing function and after a predetermined period of time, initiates a trip signal to the output function. The output function upon receiving a trip signal allows a light emitting diode to conduct and also deenergizes a contactor through which a current source is connected to the load. |
