80448608 Rev B
11
EN
Fuse Type
1,2
Fuse Selection Criteria
3
Class − J, Class − T, or Semiconductor fuses
Note:
Fuse size >= 150% Total Package Amps
4
Fuse size <= 175% Total Package Amps
4
Note:
Fuse must be Fast acting, current limiting with interrupt
rating of 200,000 amps RMS SYM.
Alternate fuse type may be used if the time vs. current
characteristics are faster then fuse types recommended.
1)
2)
This is only a recommendation and installer must follow
local and/or national codes prior to installation.
Total package current (amps) can be obtained from
IR Sales Library (
Engineering data sheets)
for any
pre−install inquiries, and from actual
Compressor
Nameplate
(contact your local IR Distributor for more
information).
1)
2)
CIRCUIT BREAKERS are NOT recommended for branch
circuit protection, due to their slow response, resulting into
inadequate protection in event of a fault.
Example of voltage imbalance calculation
U—> V 462v
V —> W 459v
W —> U 453v
V(m) = (462 + 459 + 453) / 3 = 458v
VΔ max = 462 − 453 = 9v
= (9 / 458) x 100 = 1.97%
SPECIAL ELECTRICAL CONSIDERATIONS FOR
VARIABLE SPEED DRIVE (VSD) COMPRESSORS
Primary Input Power Supply
The primary input power for the compressor can come from
different transformer sources and configurations. The most
typical sources and configurations are a wye secondary and a
delta secondary.
Wye and Delta Configurations
Wye
Delta
HOW TO GROUND
In most conditions, you must ground a wye system. Refer
to local electrical codes. When you ground a wye system,
the voltage to ground becomes stable and controlled. This
prevents a system from damage by conditions that cause
high voltage to ground. It is typical to ground the neutral
(center) point of a wye source.
It is not necessary to ground a delta system. If you ground a
delta system, ground it to one phase. You can also ground it
to a center tap on one phase.
•
Wye and Delta Grounding
Grounded wye
(typical)
Corner grounded delta
(not typical)
Ungrounded delta
(typical)
Center grounded delta
(not typical)
Refer to electrical codes to ground the compressor to a
permanent protective ground connection. The compressor
electrical enclosure contains an electrical power ground
terminal that has the identification of “PE”. The typical primary
input power is a four-wire connection with three power wires
and a ground wire. Connect the ground wire to the ground
terminal.
NOTICE
if there are only three power wires and no ground
wire, connect the ground terminal to a correct building
ground. Do not let the enclosure frame float without an
electrical connection to a power ground source.
HOW TO FIND WHICH SYSTEM IS USED
NOTICE
Use a multimeter to measure the voltage. All voltage
indications can change plus or minus 10%.
In a grounded wye connected 480-volt network:
Each phase to ground (neutral) voltage is approximately
277 volts (480/sqrt3).
277 volts is a nominal indication for 480-volt systems.
Other voltage indications are possible for 380, 415, 440
and 575-volt systems. See Table 2.
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•
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INSTALLATION
