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6
Description
This instruction manual describes the type
38-3AH3-GTD electrically operated ground
and test device suitable for insertion into
switchgear enclosures in the space normally
occupied by a circuit breaker. Refer to
E50001-F710-A236-X-XXXX instruction
manual for type GM38 switchgear and
E50001-F710-A238-X-XXXX instruction
manual for the type 38-3AH3 38 kV circuit
breaker as supplements to the discussion
of the type 38-3AH3-GTD ground and test
device in this instruction manual.
The type GM38 switchgear instruction
manual contains information on the correct
procedures to be employed in racking of the
ground and test device.
The type 38-3AH3 38 kV circuit breaker
instruction manual contains information on
handling, storage, description of operating
mechanism, field tests and maintenance
requirements.
The ground and test device system consists
of the following components:
Ground and test device
l
Remote open/close pushbutton station
l
and control cable
Test probes (cables not provided)
l
This instruction manual.
l
The following accessories may also be
required:
Racking crank
l
Manual spring charging crank
l
Either a split plug jumper or test cabinet
l
Extension rails (for cells not at floor level
l
or cells installed on a "housekeeping pad")
Lifting yoke or lift truck.
l
If required, these accessories should be
provided with the switchgear structures.
Test cables and voltage test or measurement
equipment are not provided with the ground
and test device.
Control
Electrical operation is required to
accomplish the grounding function of the
type 38-3AH3-GTD ground and test device.
Control circuits are made through a remote
open/close pushbutton station and control
cable, that is connected to the ground and
test device by use of a plug and receptacle
mounted on the ground and test device
front panel.
The "grounding" operation is enabled by
selecting the "close" function on the selector
switch mounted on the front panel of the
ground and test device. The selector switch
is operable only after specific interlock
requirements have been satisfied. Once the
"close" function has been selected, the
device may be closed to ground the upper
studs (disconnects) or lower studs
(disconnects), as determined by the device
type (refer to Table 1: Type 38-3AH3-GTD
ground and test device types on page 7) by
pushing the "close" pushbutton on the
remote pushbutton station.
The "opening" operation is enabled by
selecting the "trip" function on the selector
switch. The selector switch is operable only
after specific interlock requirements have
been satisfied. Once the "trip" function has
been selected, the device may be opened
(to disconnect the primary studs from
ground) by pushing the "open" pushbutton
on the remote pushbutton station.
Current rating
The ground and test device does not have a
continuous current rating. The ground and
test device is suitable for use in circuit
breaker cells rated 1,200 A or 2,000 A (self-
cooled) or 3,000 A (fan-cooled), without
the need for special adapters. The primary
contact finger assemblies are designed to fit
all cell continuous current ratings,
eliminating the need for special adapters.
Type 38-3AH3-GTD ground and test devices
are universal, and can be used in any type
GM38 switchgear circuit breaker
compartment.
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