Tait T809-10, Service Manual

Page: 25 / 42

MBZ-00001-01
Installation Guidelines 25
Copyright © 2004 Tait Electronics Ltd November 2004
3.4 Rack Frame Earthing
The power supply case is internally connected to the mains earth. Because the unit’s
case and the subrack guide rail are unpainted, a good electrical earthing connection
should be made between the unit and the subrack.
In addition, it is strongly advised that a further secure electrical connection is provided
by means of a dedicated earthing wire.
Warning: Failure to use a dedicated earthing wire may result in harmful voltage levels
between the subrack and the power supply, and/or miscellaneous power
supply switching noise problems in both receivers and transmitters.
3.4.1 Earthing Procedure: Method 1
To earth the power supply:
• Connect an earthing wire between the earthing stud terminal at the rear of
the T809-10, and a conveniently located screw on the subrack. The connec-
tion to the power supply’s M5 earthing stud can be made using bare wire or
a Ring/Spade Terminal.
• Ensure that a secure electrical and mechanical connection is achieved by
testing continuity.
3.4.2 Earthing Procedure: Method 2
Warning:
This method can only be used if a mechanically and electrically secure con-
nection between the –DC terminal and the subrack exists as part of the sys-
tem.
To earth the power supply:
• Connect the earthing wire from the T809-10 earthing stud terminal to a –DC
rail (0V) terminal. The earthing connection can be made between the stud
terminal and the negative output of the power supply.
• Ensure that a secure electrical and mechanical connection is achieved by
testing continuity.
Note:
Ensure that the wire cross-section specifications of the DC output connector
are observed (refer to Section 3.3.1).