| 摘要 |
The present invention is directed to an open neutral and fault detection trip circuit having minimal circuitry and low power consumption. In one embodiment, the circuit is located in a plug of an extension cord for connection between a source of power such as a service panel and a load such a window air conditioner. The circuit includes a circuit interrupter for breaking a conductive path between the line side phase and neutral conductors, and the load side phase and neutral conductors. A trip circuit is coupled to operate the circuit interrupter to break the conductive path upon detecting the opening of the line side neutral conductor which is normally referred to as open neutral condition. The trip circuit consists of a transformer having three windings coupled in subtractive polarity and a diode coupled to the circuit interrupter to provide an open neutral trip signal when the neutral conductor is open and, at the same time, a fault occurs from the phase conductor to ground. In response to an open neutral condition and a fault, the flow of current to a load such as a window air conditioner is interrupted. The circuit disclosed detects an open neutral condition with minimal circuitry and power consumption so that it can be fitted into an electrical plug. If there is an open neutral and a fault does not occur, then there is no interruption of the flow of current
|
