Transfer switch for tap-changing regulating transformers

Claim 2

A transfer switch for tap-changing regulating transformers including a. a plurality of relatively movable main contact means including a pair of fixed main contacts each adapted to be directly conductively connected to one of a pair of transformer winding taps; b. switch-over resistor means comprising at least one pair of resistors having transformer side ends and load side ends; c. a plurality of relatively movable auxiliary contact means including fixed auxiliary contacts arranged between said pair of fixed main contacts and each adapted to be conductively connected by the intermediary of said switch-over resistor means to one of said pair of transformer winding taps; d. contact operating means for effecting selective engagement and disengagement of said main contact means and of said auxiliary contact means in a predetermined sequence; e. means for forming a current path between said load side ends of said pair of switch-over resistors, said current path forming means comprising an additional resistor having an ohmic value exceeding by a power of ten the ohmic value of each of said pair of switch-over resistors and an additional switch having open and closed positions arranged in series with said additional resistor; and f. means for operating said additional switch under the control of said contact-operating means, said additional switchoperating means being adapted to effect closing of said additional switch at a first point of time prior to separation of one of said relatively movable auxiliary contact means and to effect opening of said additional switch at a second point of time following said first point of time and preceding the time of engagement of one of said relatively movable main contact means that previously has been separated.

Claim 3

A transfer switch as specified in claim 1 wherein a. said plurality of relatively movable main contact means includes one pair of movable main contacts each cooperating with one of a pair of fixed main contacts; b. said plurality of relatively movable auxiliary contact means includes one pair of movable auxiliary contacts each cooperating with one of a pair of fixed auxiliary contacts; c. each of said pair of movable main contacts and each of said pair of movable auxiliary contacts is operated by a linkage and said additional switch is operated by an additional linkage; and wherein d. a common pivotable shaft operates the linkage of each said pair of movable main contacts, the linkage of each of said pair of movable auxiliary contacts and said additional linkage of said additional switch.

Claim 4

A transfer switch arrangement including a. tapped transformer winding means having a first tap and having a second tap; b. a pair of tap-changing resistors including a first resistor conductively connected to said first tap and a second resistor conductively connected to said second tap; c. a load current-carrying line; d. switching means for disconnecting said line from said first tap and connecting said line directly to said second tap, said switching means being adapted to sequentially performing the intermediate steps of inserting but said first resistor into the current path from said first tap to said line, interconnecting said first tap and said second tap by said first resistor and said second resistor and connecting said line to a point situated between said first resistor and said second resistor, and disconnecting said first resistor from said line and inserting but said sEcond resistor into the current path from said second tap to said line; e. a third resistor having a considerably higher ohmic value than said first resistor and than said second resistor; f. additional switching means having a closed position connecting said third resistor in series with said first resistor and said second resistor across said first tap and said second tap and having an open position disconnecting said first resistor from said second resistor; g. common drive means for said switching means and said additional switching means; and h. means under the control of said common drive means for closing said additional switching means prior to disconnection of said first resistor from said line and for opening said additional switching means prior to establishment of a direct connection between said second tap and said line.

Claim 5

A transfer switch arrangement including a. tapped transformer winding means having a first tap and having a second tap; b. a pair of tap-changing resistors including a first resistor conductively connected to said first tap and a second resistor conductively connected to said second tap; c. a load current-carrying line; d. switching means for disconnecting said line from said first tap and connecting said line directly to said second tap, said switching means being adapted to sequentially performing the intermediate steps of inserting but said first resistor into the current path from said first tap to said line, interconnecting said first tap and said second tap by said first resistor and said second resistor and connecting said line to a point situated between said first resistor and said second resistor, and disconnecting said first resistor from said line and inserting but said sEcond resistor into the current path from said second tap to said line; e. a third resistor having a considerably higher ohmic value than said first resistor and than said second resistor; f. additional switching means having a closed position connecting said third resistor in series with said first resistor and said second resistor across said first tap and said second tap and having an open position disconnecting said first resistor from said second resistor; g. common drive means for said switching means and said additional switching means; and h. means under the control of said common drive means for closing said additional switching means prior to disconnection of said first resistor from said line and for opening said additional switching means prior to establishment of a direct connection between said second tap and said line.

Claim 6

A transfer switch arrangement as specified in claim 3 wherein said tapped transformer winding means include a coarse regulation winding and a fine regulation winding connected to a tap of said coarse regulation winding.

Claim 7

A transfer switch arrangement including a. tapped transformer winding means having a first tap and having a second tap; b. relatively movable main contact means including a first fixed main contact conductively connected to said first tap and a second fixed main contact conductively connected to said second tap; c. a pair of tap-changing resistors including a first resistor having a first end directly connected to said first tap and a second end remote from said first tap and a second resistor having a first end directly connected to said second tap and a second end remote from said second tap; d. relatively movable auxiliary contact means including a first fixed auxiliary contact and a second fixed auxiliary contact both arranged in the space bounded by said first fixed main contact and said second fixed main contact, said first fixed auxiliary contact being conductively connected to said first tap by the intermediary of said first resistor and said second fixed auxiliary contact being conductively connected to said second tap by the intermediary of said second resistor; e. means for selectively connecting said second end of said first resistor and said second end of said second resistor and for disconnecting said second end of said first resistor from said second end of said second resistor, said connecting and disconnecting means including an additional switch having an open position and a closed position and an additional resistor having a resistance exceeding by a power of ten the resistance of said first resistor and the resistance of said second resistor arranged in series relation to said additional switch; f. drive means for operating said relatively movable main contact means and for operating said relatively movable auxiliary contact means in a predetermined sequence, said sequence including the step of parting from said first fixed auxiliary contact of a relatively movable auxiliary contact means followed by the step of engagement of said second fixed main contact by a relatively movable main contact means; and g. means under the control of said drive means for automatically closing said additional switch prior to said step of parting and for automatically closing said additional switch prior to said step for engagement.

Claim 8

A transfer switch arrangement including a. tapped transformer winding means having a first tap and having a second tap; b. relatively movable main contact means including a first fixed main contact conductively connected to said first tap and a second fixed main contact conductively connected to said second tap; c. a pair of tap-changing resistors including a first resistor having a first end directly connected to said first tap and a second end remote from said first tap and a second resistor having a first end directly connected to said second tap and a second end remote from said second tap; d. relatively movable auxiliary contact means including a first fixed auxiliary contact and a second fixed auxiliary contact both arranged in the space bounded by said first fixed main contact and said second fixed main contact, said first fixed auxiliary contact being conductively connected to said first tap by the intermediary of said first resistor and said second fixed auxiliary contact being conductively connected to said second tap by the intermediary of said second resistor; e. means for selectively connecting said second end of said first resistor and said second end of said second resistor and for disconnecting said second end of said first resistor from said second end of said second resistor, said connecting and disconnecting means including an additional switch having an open position and a closed position and an additional resistor having a resistance exceeding by a power of ten the resistance of said first resistor and the resistance of said second resistor arranged in series relation to said additional switch; f. drive means for operating said relatively movable main contact means and for operating said relatively movable auxiliary contact means in a predetermined sequence, said sequence including the step of parting from said first fixed auxiliary contact of a relatively movable auxiliary contact means followed by the step of engagement of said second fixed main contact by a relatively movable main contact means; and g. means under the control of said drive means for automatically closing said additional switch prior to said step of parting and for automatically closing said additional switch prior to said step for engagement.

Claim 9

A transfer switch arrangement as specified in claim 5 wherein said tapped transformer winding means include a coarse regulation winding and a fine regulation winding connected to a tap of said coarse regulation winding, and wherein said first tap is on said coarse regulation winding and said second tap is on said fine regulation winding.