Introduction

The Basler Electric IFM-150 Interface Firing Module receives a control signal from a DECS-400 or DECS

450 Digital Excitation Control System and calculates a phase-control firing angle that is synchronized with

the power transformer output. The IFM-150 then generates output pulses to drive the SCRs of an

excitation rectifier chassis.

The IFM-150 is available in two configurations that control either a single-phase rectifier module or a

three-phase rectifier chassis.

Three-phase IFM-150 modules can be user-configured to supply SCR firing pulses to a fully controlled or

half controlled (positive or negative) rectifier bridge. A fully controlled rectifier bridge requires that the IFM

150 supply six sets of firing pulses to drive the SCRs of the bridge. A half controlled rectifier bridge

contains three SCRs and three diodes. Positive control is used when the SCRs are connected to the

positive side (F+) of the field output. Negative control is used when the SCRs are connected to the

negative side (F–) of the field output.

A single-phase IFM-150 provides full control of a single-phase rectifier module. Four sets of firing pulses

are generated by the IFM-150 to drive the rectifier module SCRs.