Abstract: The life of load tap changer contacts is monitored by detecting an arcing event; identifying arcing surfaces involved in the arcing event; calculating a per-unit loss of life for the identified arcing surfaces as a result of the arcing event; updating estimates of cumulative erosion for the arcing surfaces; comparing the updated estimates of cumulative erosion to a first threshold value; and signaling for action when at least one of the updated estimates of cumulative erosion exceeds the first threshold value.

Abstract: A position indicator may include a position indicator display and mechanism. A polymer housing houses the position indicator display and mechanism and a one-piece clear polymer cover encloses the position indicator display and mechanism in the polymer housing. The position indicator may further include a hinge and hand-operated latch that secures the one-piece clear polymer cover to the polymer housing such that the one-piece clear polymer cover can be opened without the use of tools.

Abstract: The life of load tap changer contacts is monitored by detecting an arcing event; identifying arcing surfaces involved in the arcing event; calculating a per-unit loss of life for the identified arcing surfaces as a result of the arcing event; updating estimates of cumulative erosion for the arcing surfaces; comparing the updated estimates of cumulative erosion to a first threshold value; and signaling for action when at least one of the updated estimates of cumulative erosion exceeds the first threshold value.

Abstract: A preventive maintenance tapping technique includes noting a tap position of a load tap changer and noting a duration that the tap position has been held. The duration that the tap position has been held is compared to a threshold value, and the tap position is changed if the tap position has been held for longer than the threshold value. Similarly, a duty cycle monitoring technique for monitoring life of load tap changer contacts includes detecting an arcing event. Arcing surfaces involved in the arcing event are identified and the effects of the arcing event on the arcing surfaces are calculated. Estimates of the erosion on the arcing surfaces are updated, and the estimates are compared to a threshold value. A signal for maintenance is generated when the estimate exceeds the threshold value.

Abstract: Automatically changing the tap position in a load tap changer includes noting a polarity of a first tap position of a load tap changer. A duration for which one or more consecutive tap positions of the load tap changer collectively have had the noted polarity also is noted. The one or more consecutive tap positions include the first tap position. The duration for which the one or more consecutive tap positions collectively have had the noted polarity is compared to a threshold value. A change is made from the first tap position to a second tap position with a polarity that is different than the noted polarity when the duration for which the one or more consecutive tap positions collectively have had the noted polarity is longer than the threshold value. A change may be made from the second tap position back to the first tap position.

Abstract: A position indicator may include a position indicator display and mechanism. A polymer housing houses the position indicator display and mechanism and a one-piece clear polymer cover encloses the position indicator display and mechanism in the polymer housing. The position indicator may further include a hinge and hand-operated latch that secures the one-piece clear polymer cover to the polymer housing such that the one-piece clear polymer cover can be opened without the use of tools.

Abstract: A rotary tap changer is connected to a power source to control voltage supplied from the power source to a load. The rotary tap changer includes a motor having an output device, and a drive sprocket having a drive shaft positioned perpendicularly to a plane of rotation of the drive sprocket. The rotary tap changer also includes a gear engaged by the drive shaft, a first set of movable contacts, and a transmission device. The first set of movable contacts is coupled to the gear and mounted to conductively engage taps of an electrical control device. The transmission device is coupled to the motor output device and to the drive sprocket such that the motor directly drives the first set of movable contacts for selecting an electrical control device tap.

Abstract: A rotary tap changer is connected to a power source to control voltage supplied from the power source to a load. The rotary tap changer includes a motor having an output device, and a drive sprocket having a drive shaft positioned perpendicularly to a plane of rotation of the drive sprocket. The rotary tap changer also includes a gear engaged by the drive shaft, a first set of movable contacts, and a transmission device. The first set of movable contacts is coupled to the gear and mounted to conductively engage taps of an electrical control device. The transmission device is coupled to the motor output device and to the drive sprocket such that the motor directly drives the first set of movable contacts for selecting an electrical control device tap.

Abstract: A tank for an oil-filled, pad-mounted electrical transformer includes six sides. The tank includes a front plate and a side panel unit connected to the front plate. The side panel unit is formed of a bent sheet of metal. Two of the side panels form obtuse included angles with adjoining side panels. A floor plate of the tank is sized to fit inside of the side panel unit so as to be capable of being secured at any desired elevation. The floor plate includes reinforcing channels.

Abstract: A transformer conductor is shaped so as to compensate for the deformation that occurs when the conductor is bent through a small radius of curvature. The shape in cross-section of the conductor may take the form of a chamfered rectangle.

Abstract: Apparatus for detecting the sufficiency and quality of an amount of dielectric material contained in the cavity of a transformer bushing is disclosed. The apparatus comprises a collar assembly which when placed over the bushing forms a capacitive element, a tunable signal producer for applying a signal to the capacitive element, a circuit for receiving, amplifying and rectifying the output signal from the capacitive element, and an indicator to detect and indicate the dielectric condition or capacitance of the capacitive element and thus the sufficiency and/or quality of the dielectric material within said bushing assembly. The collar assembly in one embodiment comprises a pair of electrically conductive segments which are hinged together for positioning about the bushing. The interior surfaces of the collar assembly are shaped to conform substantially to the outer shape of the transformer bushing.