User Manual Chapter 2
GFK-2749A Jan 2020
Installation 25
2.6 Wiring
WARNING
HIGH VOLTAGE; HIGH CURRENT
DO NOT TOUCH the connectors or wiring after powering up the PSM system. Hazardous
voltages exist, and death or injury may result.
The Terminal Assembly frame ground connection must always be installed and must be
installed before any other wiring is attached.
Fuses on the voltage inputs are mandatory.
Potential transformers are mandatory. Fuses on input and output leads for the PTs are
mandatory. The COM1 and COM2 terminals must be connected to frame ground to
maintain a common reference.
COM1 and COM2 terminals shall not be used for neutral or protective earth connections.
Certain fault conditions can cause the neutral line to be pulled to the full phase to neutral
voltage, posing a danger to personnel and potentially damaging the Terminal Assembly.
Current Transformer (CT) shorting bars are mandatory. One leg of each CT secondary should
be solidly connected to frame ground to ensure that the current inputs remain at a safe
potential, and to reduce the noise induced into the system.
To reduce risk of electric shock or damage to the attached CTs, always open or disconnect
all voltage circuits and apply the shorting bar connections to the current inputs before
installing or servicing the connections to the Terminal Assembly.
Never disconnect the GRID 1 or GRID 2 field wiring while power is present. Personal injury or
equipment damage may result. Finger guards must be installed on the Terminal Assembly
before energizing the field wiring.
Wiring to the PSM consists of
•
Frame ground connections from the Terminal Assembly to the chassis.
•
The connection cable between the Terminal Assembly and the PSM
•
The leads to user-supplied potential transformers and current transformers
•
ync relay output connections
Note: No CT shorting bars are provided on the PSM Terminal Assembly; these must be supplied by
the user.
2.6.1 General Wiring Notes
In the following connection diagrams, the line connections are labeled L1, L2, and L3. When
you wire the Terminal Assembly into a system, you must decide which line will correspond
to which phase. Usually, L1 will correspond to phase A, L2 with phase B, and L3 with phase
C. Once you decide how to connect the system, the labels L1, L2 and L3 can be changed to
A, B, and C according to your system configuration. Then the diagrams can be followed, and
the connections made.
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