Karel MS48 Installation & Maintenance Guide
Edition 3.2
37
The chassis ground is established through the mains cable of the system, which is
equipped with the ground wire. Therefore, if the mains outlet has a proper ground,
there is no need to make any extra connections for the chassis ground. Due to this
reason, it is recommended to operate the system over a mains plug that is properly
grounded.
Checking whether the mains ground is proper or not requires special devices. But it
is possible to have a rough idea about the mains ground simply by measuring the
voltage across:
•
The phase and the neutral; it must be in range of 180 VAC and 260 VAC.
•
The ground and the neutral; it must be 1-2 VAC.
If mains ground is not satisfactory, the system chassis can be connected to a hot or
cold water pipe, which may serve as the ground surface of your system, through the
ground screw (labeled with ) at the down left corner of the system cabinet, to
which the ground wire of the mains cable is connected. For such cases, it is of
course better to construct an ideal ground, simply by inserting a metal bar (of at
least 1.5 m length and 1.5 cm radius, copper is preferable) into the earth, as
illustrated in the following figure.
Figure B-3
II.2.
SPS48 POWER SUPPLY MODULE
The SPS48 Power Supply Module, including the power card with cables, comes
already installed in the system cabinet, below the metal cage surrounding the
RNT48 and PWT48 transformers.
The SPS48 card is connected to MB48 motherboard via the 7-pin flat cable. Also,
the 3-pin connector at the end of the cable coming from PWT48 power transformer
as well as the 4-pin connector at the end of the cable coming from RNT48 ring
transformer are attached to the corresponding connectors on SPS48 card.
The output of the RNT48 ring transformer, which is in fact the ring signal itself, is
directly transferred to the MB48 motherboard. For this, the 2-pin connector at the
end of the cable coming from RNT48 is attached to the corresponding connector on
MB48.
Summary of Contents for MS48
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