Interface Relay Unit

Question 1

Interface Relay Unit Overview

Answer 1

The IRU interlocks VOBC outputs to ensure vital and non-vital outputs are disconnected from the EU when the train is operating in RM.

Question 2

IRU Components

Answer 2

Relay Assembly
Protection Filter
Front Panel Connectors

Question 3

Relays

Answer 3

FARs in the IRU control vital/non-vital trainlines in auto and PM modes, disconnect power to these trainlines on command or if there is a failure, convert the VOBC output voltages from 24V dc to 110V dc.

Question 4

Protection Filter

Answer 4

The protection filter modules provide over-voltage suppression and over-current protections for the VOBC and convert the trainlines 110V dc to 27V dc for the VOBC