Alstom SHPM 101 - Quadramho Module Earthing Arranging

SERVICE MANUAL R5888C
QUADRAMHO Chapter 2
Appendix A
Page 2 of 71
Figure 2: Quadramho module earthing arrangement
Relay room earth
Signal and power commons to modules
CURRENT INPUT MODE
POWER SUPPLY
RELAY CASE
VOLTAGE IMPUT MODULE
4mm Plug & Socket
Case earth stud
Ground plane on relay multilayer pcb backplate
A
B
Source A: Common mode surge from ac current to ac voltage terminals Source B: Common mode surge from dc supply to case terminals