Overview: The Model 276B3 is a ring-type 3-phase current transformer (CT) designed for monitoring currents ranging from 50 to 1200 amps. It features an accuracy rating of ±2% for 50-100 amp CTs and ±1% for currents over 100 amps at 60 Hz. The CT operates within a frequency range of 25-400 Hz and includes #8-32 brass secondary terminals and mounting brackets. Polarity markings are clearly stamped on the transformer.

Specifications: The Model 276B3 is UL Recognized and CSA Certified. It includes corner holes for mounting plate attachment. The CT is available in various part numbers, each with specific ratios, maximum VA for 1% accuracy, and secondary winding resistance at 167º F. For example, the 276B3-50 has a ratio of 50:5, a max VA of 2.5, and a resistance of 0.0153.

Primary Turn Ratio Modification: The CT's nameplate rating assumes a single pass of the primary conductor through the transformer window. This rating can be adjusted by looping the conductor multiple times through the window, effectively reducing the rating in even multiples.

Secondary Turn Ratio Modification: The CT's ratio can be modified by altering the number of secondary turns. Adding turns decreases secondary output for the same primary amperage, while subtracting turns increases it. For example, adding 5 secondary turns to a 300:5 CT requires 325 amps on the primary to maintain a 5 amp secondary output.

Troubleshooting: If the unit fails to operate properly, contact the manufacturer at 800-862-2875.

Warranty: The Model 276B3 is warranted to be free from defects in materials and workmanship for one year from the date of purchase. The warranty covers repair or replacement.

Safety and Installation: The device contains potentially hazardous voltages. All electrical power should be removed when connecting or disconnecting wiring. Installation and servicing should be performed by qualified personnel.