US 7,592,924 B2
Intelligent life testing methods and apparatus for leakage current protection
Feng Zhang, Shanghai (China); Hongliang Chen, Shanghai (China); Fu Wang, Yueqing Zhejiang (China); Wusheng Chen, Yueqing Zhejiang (China); Yulin Zhang, Shanghai (China); and Huaiyin Song, Yueqing Zhejiang (China)
Assigned to General Protecht Group, Inc., Zhejiang (China)
Filed on Oct. 25, 2006, as Appl. No. 11/588,048.
Claims priority of application No. 2006 1 000785 (CN), filed on Feb. 21, 2006.
Prior Publication US 2007/0195470 A1, Aug. 23, 2007
This patent is subject to a terminal disclaimer.
Int. Cl. G08B 21/00 (2006.01)
U.S. Cl. 340—638  [340/635; 324/527; 361/42] 20 Claims
OG exemplary drawing
 
1. An apparatus for testing the life of a leakage current protection device, wherein the leakage current protection device has a first input, a second input, a third input, a fourth input, a first output, a second output, a trip switch having two LINE terminals that are electrically coupled to the first input and the second input, respectively, and two LOAD terminals that are electrically coupled to the inputs of an electrical appliance, respectively, a reset circuit having an input that is electrically coupled to the third input, and an output that is electrically coupled to the first output, and a trip coil circuit having a switching device that has a gate, an anode, and a cathode, a first input that is electrically coupled to the output of the reset circuit and the first output, a second input that is electrically coupled to the fourth input, an output that is electrically coupled to the second output, comprising:
(i) a microcontroller unit (MCU) having a first input that is electrically coupled to the second output of the leakage current protection device, a second input, a first output that is electrically coupled to the third input of the leakage current protection device, a second output, a third output, a fourth output that is electrically coupled to the second input of the trip coil circuit and the fourth input of the leakage current protection device, and a power supply input P;
(ii) a power grid signal synchronization monitoring circuit having an input that is electrically coupled to the first output of the leakage current protection device, and an output that is electrically coupled to the second input of the MCU;
(iii) an alarm circuit having an input that is electrically coupled to the third output of the MCU, and a power supply input;
(iv) a power supply circuit having an input that is electrically coupled to the first output of the leakage current protection device, and an output that is electrically coupled to the power supply input P of the MCU and the power supply input of the alarm circuit; and
(v) a ground fault simulation unit having an input that is electrically coupled to the second output of the MCU, a first output that is electrically coupled to the first input of the leakage current protection device, a second output that is electrically coupled to the second input of the leakage current protection device,
wherein, in operation, the power grid signal synchronization monitoring circuit generates a first signal that is synchronized with an AC power from the first input and the second input of the leakage current protection device to form a power grid signal synchronization signal, the power grid signal synchronization signal is electrically coupled to the second input of the MCU, the MCU generates a pulse signal before the power grid signal synchronization signal reduces to zero volt during every positive half-wave of the AC power, and a second signal from the second output to the ground fault simulation unit to generate a simulated ground fault signal, the gate of the switching device receives the pulse signal and a third signal in responsive to the simulated ground fault signal, the MCU receives a DC voltage at the first input of the MCU, and the MCU compares the DC voltage with a predetermined threshold value to determine whether a fault exists in the leakage current protection device, and activates the alarm circuit if at least one fault exists.