US 11,674,985 B2
Electrical safety monitoring system utilizing a heartbeat signal indicative of voltage present on line inputs
Philip Brown Allen, Davenport, IA (US); and Mark Alan Hockert, Davenport, IA (US)
Assigned to GRACE TECHNOLOGIES, INC, Davenport, IA (US)
Filed by Grace Technologies, Inc., Davenport, IA (US)
Filed on Aug. 24, 2021, as Appl. No. 17/410,503.
Application 17/410,503 is a continuation of application No. 16/191,229, filed on Nov. 14, 2018, granted, now 11,150,277.
Claims priority of provisional application 62/585,891, filed on Nov. 14, 2017.
Prior Publication US 2021/0382093 A1, Dec. 9, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. G01R 19/155 (2006.01); G01R 19/25 (2006.01)
CPC G01R 19/155 (2013.01) [G01R 19/2513 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An electrical safety monitoring system comprising:
a housing;
a plurality of visual indicators operatively connected to the housing;
an analog circuit disposed within the housing and having line inputs for hardwiring a first line (L1), a second line (L2), a third line (L3), and a ground (GND), wherein each of the line inputs is a three-phase connection, wherein the analog circuit is configured to monitor if voltage exists between any two of the line inputs and further configured to visually indicate presence of voltage on each of the line inputs using the plurality of visual indicators operatively connected to the housing;
a heartbeat circuit electrically connected to the analog circuit to provide a heartbeat signal indicative of voltage present on any of the line inputs, the heartbeat signal encoding state information for each of the line inputs for the first line (L1), the second line (L2), the third line (L3) and the ground (GND);
an isolated voltage source electrically connected to the heartbeat circuit to power the heartbeat circuit with a VDC+ and a VDC−;
a logic circuit in operative communication with the heartbeat circuit for monitoring input from the heartbeat circuit and decoding the input from the heartbeat circuit to determine state information for each of the line inputs for the first line (L1), the second line (L2), the third line (L3) and the ground (GND).