Siemens Energy & Automation, Inc.

Siemens Power Transmission & Distribution, Inc.

Stuart R Akers

A lockable circuit breaker racking mechanism is provided with a breaker type detection mechanism preventing locking and removal of the key unless the correct breaker type has been installed. The same locking mechanism can also be used to secure the racking mechanism in the trip-free position.

Lockable position interlock for rackable circuit breakers

An under voltage trip device for low and medium voltage breakers is disclosed. A first power supply receives unregulated power from a control voltage supply which is rectified and regulated with portions of the power supply monitored by a processor. The output of the first power supply is supplied to a second power supply which allows pulsing modulating power to be supplied to a solenoid connected thereto. The current supplied to the solenoid is measured and calculated by the processor and stored therein as well as being compared to stored values, thereby determining solenoid armature position and predicting or warning of solenoid failure. Connected to the second power supply is a third power supply which operates in a voltage regulator supply mode and a switcher mode during start-up and continuous running operation respectively, such mode being controlled by the processor. Switches are connected to the processor so that multiple control voltage sources may be selected and so that the delay time and pick-up or drop-out points with respect to the control voltage may be adjusted in order to determine operation of the solenoid and the position and condition of the solenoid armature and coil. The solenoid is pulsed with higher than rated voltages in order to firmly lock in the solenoid and to delay its decay during an undervoltage condition from the control voltage supply.

Trip device for an electric powered trip unit

An under voltage trip device for low and medium voltage breakers, a first power supply receives unregulated power from a control voltage supply, which is rectified and regulated with portions of the power supply monitored by a processor. The output of the first power supply is supplied to a second power supply which allows pulsing modulating power to be supplied to a solenoid connected thereto. The current supplied to the solenoid is measured so as to represent the solenoid armature position which is measured and calculated by a processor and stored therein as well as being compared to stored values, thereby determining solenoid armature position and predicting or warning of solenoid failure. Connected to the second power supply is a third power supply which operates in a voltage regulator supply mode and a switcher mode during start-up and continuous running operation respectively, such mode being controlled by the processor. Switches are connected to the processor with the result that multiple control voltage sources may be selected while the position and condition of the solenoid armature and coil are determined. Further, the solenoid is pulsed with higher than rated voltages in order to firmly lock in the solenoid and to delay its decay during an under-voltage condition from the control power. Further, the power supply circuit in cooperation with the DIP switches and the processor allows for adjustment for the delay time and pick-up or drop-out points with respect to the control voltage in order to determine operation of the solenoid.

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Raleigh, NC, United States of America

Stuart R Akers