Meramec Instrument Transformer Co

Internally Mounted Dry-Type Bushing Current Transformer

Application:

The internally mounted Dry-type Transformer BCT is designed to be mounted onto the high voltage bushing of a dead-tank power circuit breaker along the ground collar, protected by an external cover. It can also be installed inside a weather-tight cabinet or inside an MC switchgear compartment. When properly installed, the Dry-type BCT can be used on higher system voltage levels while maintaining its own mere 600 Volt class rating. Its simple construction provides a low leakage product with extremely high short circuit capabilities.

Construction:

The toroidal core is continuously tape wound using cold rolled grain oriented electrical grade silicon steel, which receives a full stress relief anneal after it is wound to its specified dimensions. The secondary winding is then wound of insulated copper magnet wire over the cellulose insulated core with the turns equally spaced around the core periphery. When taps are pulled, they are wound in a manner that assures a fully distributed winding between any connections. The coil is then finished with a polyester film tape. All materials used have a minimum rating of 105°C.

Connections:

The primary polarity H1/P1 is identified on its surface by a black stripe which folds over the side. Secondary leads are typically #10 or #12 AWG available in grey Tefzel, or PVC, THHN and SIS in colored coded bundles or single colors with markings to identify the terminal. They are also available with ¼” ring tongue terminal in lieu of leads. The X1/S1 terminal represents the instantaneous polarity reference with respect to H1/P1.