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US 8,421,639 B2Granted
Branch current monitor with an alarm
AssigneeVeris Industries, LLC
InventorsMichael Bitsch, Marc Bowman
Life of this patent
Estimating the term…
Abstract
A power meter for monitoring current in a power cable annunciates an alarm if the current transgresses one or more alarm current limits. False alarms are avoided by delaying the activation of the alarm for a delay interval following determination that current is flowing in the monitored conductor.
Claims9
A meter for monitoring electric current in a conductor, said meter comprising:
- (a) a timer to transmit a delay signal indicating elapsing of a delay interval following initiation of a flow of current in said conductor;
- (b) a first alarm responsive to detection of a first alarm current having a magnitude less than a first lower limit current, said first alarm responsive to detection of said first alarm current only after transmission of said delay signal;
- (c) a second alarm responsive to detection of a second alarm current having a magnitude less than a second lower limit current and greater than said first lower limit current, said second alarm responsive to detection of said second alarm current only after transmission of said delay signal;
- (d) a third alarm responsive to detection of a third alarm current having a magnitude greater than a first upper limit current, said third alarm responsive to detection of said third alarm current only after transmission of said delay signal;
- and
- (e) a fourth alarm responsive to detection of a fourth alarm current having a magnitude greater than a second upper limit current and less than said first upper limit current, said fourth alarm responsive to detection of said fourth alarm current only after transmission of said delay signal.
3 more elements
A method of monitoring electric current, said method comprising the steps of:
- (a) repeatedly sampling a magnitude of current in a conductor;
- (b) if current is detected in said conductor, determining if an errant current alarm is activated;
- (c) if said errant current alarm is not active, timing an interval from an initial detection of current in said conductor;
- (d) activating said errant current alarm when said interval exceeds a delay interval;
- (e) if said errant current alarm is activated, comparing said magnitude of said detected current to a first alarm current limit;
- (f) if said magnitude of said detected current is less than said first alarm current limit, annunciating a first alarm signal;
- (g) if said errant current alarm is activated, comparing said magnitude of said detected current to said first alarm current limit and a second alarm current limit;
- (h) if said magnitude of said detected current is greater than said first alarm current limit and less than said second alarm current limit, annunciating a second alarm signal;
- (i) if said errant current alarm is activated, comparing said magnitude of said detected current to a third alarm current limit;
- (j) if said magnitude of said detected current is greater than said third alarm current limit, annunciating a third alarm signal;
- (k) if said errant current alarm is activated, comparing said magnitude of said detected current to said third alarm current limit and a fourth alarm current limit;
- and
- (l) if said magnitude of said detected current is greater than said fourth alarm current limit and less than said third alarm current limit, annunciating a fourth alarm signal.
10 more elements
Dependencies are inferred from the claim text.