TESTER AT4557
This is a tester used for checking relay current adjustments other than double coil bridge types.  It is used in conjunction with a TRT27, which is a resistance box.

Dimensions
18" x 13.25" x 8".

Drawings - 63540 and 70417.

Diagram - AT 4557.

Specification - T4328.

Description - EI Tests and Inspections, General,  B1520.
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Last revised: December 05, 2025
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