US 8,138,433 B2 · Sequenced separately-derived transfer switch capable of switching a load between a pair of power supplies without introducing open neutral switching transients

Abstract

An interlock arrangement operatively associated with utility and generator side switches of an electrical panel including a first main switch associated with the first power supply and a second main switch associated with the second power supply. The interlock arrangement includes a first neutral switch associated with the first power supply, and a second neutral switch associated with the second power supply. A lockout sequencer arrangement has a first lockout that restricts simultaneous switching of the first and the second neutral switch, a second lockout configured to engage the first lockout to restrict movement of the first lockout when the first main switch is a conductive position, and a third lockout configured to engage the first lockout to restrict movement of the first lockout when the second main switch is in a conductive position.

Claims21

Dependent claims

A lockout assembly for use with a separately-derived transfer switch having a mains switch, a generator switch, a mains neutral switch, and a generator neutral switch, the arrangement comprising:

a neutral interlock associated with the mains neutral switch and the generator neutral switch, and configured to prevent both neutral switches from being in a conductive position simultaneously, the neutral interlock including a first bracket engaged with the mains neutral switch and a second bracket engaged with the generator neutral switch, the brackets adapted to move in response to movement of a neutral switch;
a first interlock configured to engage the first bracket to prevent movement of the first bracket and a second interlock configured engage the second bracket to prevent movement of the second bracket;
and
wherein the first and second interlocks are arranged such that the interlocks cannot be engaged with their respective brackets simultaneously.

1 more element

A separately-derived transfer switch for switchably connecting a load to either a first power supply or a second power supply, the transfer switch comprising:

a first main switch associated with the first power supply;
a second main switch associated with the second power supply;
a first neutral switch associated with the first power supply;
a second neutral switch associated with the second power supply;
a lockout sequencer arrangement having a first lockout that restricts simultaneous switching of the first and the second neutral switches, a second lockout configured to engage the first lockout to restrict movement of the first lockout when the first main switch is a conductive position, and a third lockout configured to engage the first lockout to restrict movement of the first lockout when the second main switch is in a conductive position.

2 more elements

Dependencies are inferred from the claim text.

Sequenced separately-derived transfer switch capable of switching a load between a pair of power supplies without introducing open neutral switching transients

Life of this patent

Sequenced separately-derived transfer switch capable of switching a load between a pair of power supplies without introducing open neutral switching transients

Life of this patent

Abstract

Claims21