This part is a kind of semiconductor called AT655.

Function of this product has PHASE CONTROL THYRISTOR.

Manufacturers : Power Semiconductors

Image and pinout :

Some of the text within the PDF file :

ANSALDO Ansaldo Trasporti s.p.a. Unita' Semiconduttori Via N. Lorenzi 8 - I 16152 GENOVA - ITALY Tel. int. +39/(0)10 6556549 - (0)10 6556488 Fax Int. +39/(0)10 6442510 Tx 270318 ANSUSE I - PHASE CONTROL THYRISTOR AT655 Repetitive voltage up to Mean on-state current Surge current 2800 V 1545 A 30 kA FINAL SPECIFICATION feb 97 - ISSUE : 03 Symbol Characteristic Conditions Tj [°C] 125 125 125 Value Unit BLOCKING V V V I I RRM RSM DRM RRM DRM Repetitive peak reverse voltage Non-repetitive peak reverse voltage Repetitive peak off-state voltage Repetitive peak reverse current Repetitive peak off-state current V=VRRM V=VDRM 2800 2900 2800 70 70 V V V mA mA 125 125 CONDUCTING I I I V V r T (AV) T (AV) TSM Mean on-state current Mean on-state current Surge on-state current I² t O [ ... ]

AT655 PDF Datasheet Download