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Chapter 2: Safety
Precautions
There is a hazard of electric shock whenever working on or
near electrical equipment. Turn off all power supplying the
equipment before starting work. Lock out the disconnecting
means in accordance with NFPA 70E
Requirements for Employee Safety In the Workplace."
Where it is not feasible to de-energize the system, take the
following precautions:
1.
Instruct persons working near exposed parts that are or
may be energized to use practices (including appropriate
apparel, equipment and tools) in accordance with
NFPA 70E.
2.
Require persons working on exposed parts that are or
may be energized to be qualified persons who have
been trained to work on energized circuits.
Only qualified electrical personnel with training and
experience with medium voltage equipment (>1000 V) shall
be permitted to work on this apparatus. They shall be familiar
with the work to be performed, as well as industry and local
safety procedures and standards.
In addition, this person should have the following
qualifications:
1.
Be trained and authorized to energize, de-energize, clear,
ground, and tag circuits and equipment in accordance
with established safety practices.
2.
Be trained in the proper care and use of protective
equipment such as rubber gloves, hard hat, safety
glasses or face shields, flash clothing, etc., in
accordance with established practices.
3.
Be trained in rendering first aid.
4.
Be knowledgeable with respect to electrical installation
codes and standards, for example, the National Electrical
Code (NEC).
Read and understand all instructions before attempting
installation, operation, or maintenance of the medium
voltage drive.
Disconnect all low and medium voltage power sources to the
drive or the medium voltage control-gear before working on
the equipment. Lockout procedures must be followed. Verify
that the voltage has been removed. Observe all local and
national codes and standards
Safety features
The medium voltage drive has many safety features to help
ensure the safety of operators and maintenance personnel.
Incoming voltage is disconnected from the downstream
portion of the circuit by the isolation switch in the incoming
section of the drive. The isolation switch is interlocked with
the medium voltage door in the incoming section to prevent
®
, "Electrical Safety
SC9000 EP medium voltage drives IB020001EN—February 2016 www.eaton.com
access to the compartment before the switch is opened.
The switch is interlocked with the main contactor to prevent
opening the switch under load. The switch operating
mechanism is also interlocked to prevent closing the switch
with the door open. A viewing window is provided to verify
the switch position before entering the medium voltage
compartment. Other medium voltage doors are also
interlocked to prevent access until the switch is open as
well. Distinctive marking on back of switch assembly
appears when shutter barrier is in position and starter is
completely isolated from the line. Grounding clips provide a
positive grounding of the SC9000 EP AFD and main fuses
when the isolating switch is opened. High and low voltage
circuits are compartmentalized and isolated from each other.
The drawout isolation switch is easily removed by loosening
two bolts in the back of the switch. The shutter remains in
place when the switch is withdrawn (shutter shown in users
manual in Chapter 5, but not in this installation manual).
Grounding device is provided for shorting the DC bus to
ground before entering the medium voltage compartments.
The operating mechanism has provision for lockout/tagout.
All local and other procedures should be followed to ensure
safe operation.
DC link capacitors
WARNING
High storage device, do not enter drive until capacitors
have discharged.
The DC Link consists of a large, medium voltage capacitor
bank charged to a maximum of 7500 Vdc for 4160 V drives,
5940 Vdc for 3300 drives, and 4320 Vdc for 2400 V drives.
The capacitors require 5 minutes to discharge to 50 Vdc after
the main contactor is opened. Verify on the keypad that the
DC voltage has discharged before entering the compartment.
Follow verification and grounding procedures before installing
or servicing the equipment.
Grounding practices
WARNING
The SC9000 EP must be solidly grounded.
The inverter must be grounded in accordance with Article
250 of the National Electrical Code or Section 10 of the
Canadian Electrical Code, Part I. The grounding conductor
should be sized in accordance with NEC Table 250.122 or
CEC, Part I Table 16. The SC9000 EP is supplied with a
ground bus that runs the length of the drive. If the drive
is shipped in sections, be sure that the ground bus
connection splices are installed across all shipping splits.
This ground bus must be solidly connected to the building
ground grid. The ground connection is required for proper
drive operation. The ground connection is required for
personal safety. THE METAL OF CONDUIT IS NOT AN
ACCEPTABLE GROUND.
Chapter 2: Safety
3
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