Power Bridge Firing Interface

This portion of the ECM-2 module provides SCR firing commands to the DECS-2100 system Bridge

Control Modules. In turn, each Bridge Control Module controls the level of dc output power supplied by

the corresponding power bridge. Power bridge output is determined by a control signal supplied from the

excitation control circuitry to the firing control logic. To generate the SCR firing signals, the firing control

circuitry creates timing signals that are time- and pattern-synchronized with the monitored, three-phase

PPT voltage. (The PPT voltage is monitored by way of an Isolation Transducer connected to the ECM-2

module’s PPT fiber-optic input.) The firing signals, interspersed with data signals, are transmitted to the

DECS-2100 system Bridge Control Modules via fiber-optic connections.

In its standard configuration, the ECM-2 module can control from one to four sets of Bridge Control

Modules and power bridges. In its optional configuration, up to 16 sets of Bridge Control Modules and

power bridges can be controlled.

In addition to power bridge control, this circuitry processes power bridge alarms received from the Bridge

Control Modules and provides the alarm data to the excitation control logic. Processed alarms include

SCR loss, high power bridge temperature, and low power bridge temperature.