Leakage current interrupter with sustained overvoltage and/or overcurrent protection
2 Assignments
0 Petitions
Accused Products
Abstract
An appliance leakage current interrupter (ALCI) includes components for preventing sustained over-voltage and sustained over-current conditions. A current interruption threshold is inversely proportional to voltage supplied to the appliance. A microprocessor measures the voltage level of the incoming AC mains supply. The microprocessor is coupled to a sub-circuit for intentionally inducing a current mismatch between the two power lines monitored by the ALCI. Upon detecting an over-voltage of sufficient magnitude and duration, the microprocessor induces a current mismatch in the power lines, thereby causing the ALCI to interrupt power. A second current sensing transformer monitors one of the power lines. The microprocessor also receives the output of the second current sensing transformer. Upon detecting a current level exceeding a variable threshold, the microprocessor induces a current mismatch in the power lines and causes the ALCI to interrupt power.
30 Citations
34 Claims
-
1-9. -9. (canceled)
-
10. A circuit for interrupting power to an appliance, comprising:
-
a current detector providing an imbalance signal when current through first and second power supply lines is unbalanced by more than a predetermined amount;
an interruption switch for interrupting current flow through at least one of the first and second supply lines;
a ground fault detection sub-circuit configured to open the interruption switch upon receipt of the imbalance signal;
a fault-inducing switch connecting the first and second supply lines and causing a current imbalance between the first and second supply lines when closed;
an over-voltage detection sub-circuit configured to receive a signal indicative of voltage supplied to the appliance, and further configured to close the fault-inducing switch when the supplied voltage exceeds a voltage threshold VTRIP;
at least one TEST switch, the closure of which causes the over-voltage detection sub-circuit to receive a signal indicative of a supplied voltage exceeding VTRIP; and
at least one externally-visible light-emitting component, and wherein the over-voltage detection sub-circuit is further configured;
to determine, upon closure of the TEST switch, whether a signal corresponding to a supplied voltage exceeding VTRIP has been detected, to close the fault-inducing switch upon determining that a signal corresponding to a supplied voltage exceeding VTRIP has been detected, and to activate the at least one light-emitting component so as to indicate a malfunction upon determining that a signal corresponding to a supplied voltage exceeding VTRIP has not been detected.
-
-
11. A circuit for interrupting power to an appliance, comprising:
-
a current detector providing an imbalance signal when current through first and second power supply lines is unbalanced by more than a predetermined amount;
at least one interruption switch for interrupting current flow through at least one of the first and second supply lines;
a ground fault detection sub-circuit configured to open the at least one interruption switch upon receipt of the imbalance signal;
a fault-inducing switch connecting the first and second supply lines and causing a current imbalance between the first and second supply lines when closed; and
an over-current detection sub-circuit configured to receive a signal indicative of current supplied to the appliance, and further configured to close the fault-inducing switch when the supplied current exceeds a current threshold ATRIP. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
-
27. A circuit for interrupting power to an appliance, comprising:
-
an interruption switch for interrupting current flow through at least one of first and second supply lines supplying power to an appliance;
an over-voltage detection sub-circuit configured to receive a signal indicative of voltage supplied to the appliance, and further configured to open the interruption switch when the supplied voltage exceeds a voltage threshold VTRIP for a period of time tV — TRIP; and
an over-current detection sub-circuit configured to receive a signal indicative of current supplied to the appliance, and further configured to open the interruption switch when the supplied current exceeds a current threshold ATRIP for a period of time tA — TRIP. - View Dependent Claims (28, 29, 30, 31)
-
-
32. A circuit for interrupting power to an appliance, comprising:
-
means for a detecting an imbalance of current flowing through first and second power supply lines supplying power to an appliance;
means for interrupting current flow through at least one of the first and second supply lines upon detection of a current imbalance;
means for determining when current supplied to the appliance has exceeded a current threshold ATRIP for a period of time tA — TRIP; and
means for causing a current imbalance when the supplied current has exceeded ATRIP for tA — TRIP. - View Dependent Claims (33, 34)
-
Specification