Delayed contact closing apparatus and method for capacitors

A multi-phase capacitor switcher that switches grounded capacitors into a multi-phase AC power line, comprising:

• a first grounded capacitor;
• a second grounded capacitor;
• a third grounded capacitor;
• a controller that monitors the voltage in at least one phase of the power line;
• a first capacitor switch having a movable contact and a stationary contact, said first switch having an open position wherein said stationary contact is positioned at a first distance from said movable contact, a closed position wherein said movable contact is in contact with said stationary contact, and a transition position wherein the movable contact moves towards the stationary contact at a predetermined velocity;
• said first capacitor switch coupling said first capacitor to the first phase of said multi-phase line when in said closed position;
• a second capacitor switch having a movable contact and a stationary contact, said second switch having an open position wherein said stationary contact is positioned at a second distance greater than the first distance from its respective movable contact, a closed position wherein said movable contact is in contact with said stationary contact, and a transition position wherein said movable contact moves toward said stationary contact at a predetermined velocity;
• said second capacitor switch coupling said second capacitor to the second phase of said multi-phase line when in said closed position;
• a third capacitor switch having a movable contact and a stationary contact, said third switch having an open position wherein said stationary contact is positioned at a third distance greater than the second distance from its respective movable contact, a closed position wherein said movable contact is in contact with said stationary contact, and a transition position wherein said movable contact moves toward said stationary contact at a predetermined velocity;
• said third capacitor switch coupling said third capacitor to the third phase of said multi-phase line when in said closed position;
• said controller coupled to said first, second and third capacitor switches;
• said first, second and third capacitor switches gang controlled so that they transition from the open position to the transition position at substantially the same time;
• said controller targeting the closure of said first switch shortly after said voltage signal crosses voltage zero;
• said second distance arranged so that the second switch closes more than one-quarter of one AC cycle after said first switch closes;
• and
• said third distance arranged so that the third switch closes more than one-quarter of one AC cycle after said second switch closes.

A transient reducing capacitor switching device that switches grounded capacitors into a power line having at least three phases, wherein said at least three phases each transmits AC voltage, comprising:

• a first switch coupled to a first grounded capacitor for switching said first capacitor into a first phase;
• a second switch coupled to a second grounded capacitor for switching said second capacitor into a second phase;
• a third switch coupled to a third grounded capacitor for switching said third capacitor into a third phase;
• a switch controller that monitors the voltage in at least one phase;
• said controller switching said first grounded capacitor into said first phase substantially when said voltage signal in said first phase crosses zero potential;
• said controller switching said second grounded capacitor into said second phase at least one-fourth of one AC cycle after said first grounded capacitor was switched into said first phase, and substantially when said voltage signal in said second phase crosses zero potential;
• said controller switching said third grounded capacitor into said second phase at least one-fourth of one AC cycle after said second grounded capacitor was switched into said second phase, and substantially when said voltage signal in said third phase crosses zero potential.

A method of reducing transients during switching of capacitors into multi-phase power lines transmitting AC voltage, comprising the steps of:

• monitoring the voltage in at least one phase of said power line;
• switching a first capacitor into a first phase of said power line substantially when the voltage in said first phase is at zero potential;
• and
• delaying until after the voltage in a third phase of said power line crosses zero potential and then switching a second capacitor into a second phase of said power line substantially when the voltage in said second phase is at zero potential.

A method of switching grounded capacitors into a three-phase voltage transmission line, comprising the steps of:

• switching a first grounded capacitor into the first phase of said line;
• delaying to let any transients caused during the first switching to diminish;
• switching a second grounded capacitor into the second phase of said line;
• delaying to let any transients caused during the second switching to diminish;
• and
• switching a third grounded capacitor into the third phase of said line.