Class 8998 Motor Control Centers
Sample Specifications
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2.14 Optional Isolation/Bypass Contactors
a. The AC drive controller unit shall include a UL Listed option [NEMA rated isolation and bypass
contactors packaged as a separate MCC unit with steel barriers segregating the AC inverter from
the bypass starter] [IEC rated is olation and bypass contactors integrated with the AC inverter as one
MCC unit to reduce space] complete with thermal overload relay, disconnect interlocked with the
door, control circuit transformer, motor flux decay timer, and an AFC/OFF/BYPASS switch. The
operator shall have full control of the bypass starter by operation of the door-mounted selector
switch.
2.15 Harmonic Analysis
NOTE:The amount of harmonic distortion at the point of common coupling (PCC) is due to the
distribution system characteristics (impedance of the source) and the power source size relative to the
AC drive load. The harmonic current magnitude and v oltage dis tortion va lues can b e pr edicted thro ugh
computer modeling. If the resulting calculations determine that th e harmonic dist ortion will be abo ve the
IEEE-519 specification of 5%, a line reactor can be supplied to lower the harmonic levels. The line
reactor is mounted at the AC drive input to reduce the current harmonics that are fed back into the
supply.
a. A harmonic analysis shall be performed and priced as a separate line item by the AC drive controller
unit manufacturer based upon system documentation consisting of, but not limited to, one-line
diagrams and specific distribution transformer information c onsisting of kV A, %Z, an d X/R data. The
data shall consist of but not be limited to total harmonic voltage distortion and total rms current.
b. The line reactor, if required, shall be provided as a separate, ventilated [NEMA Type 1 Gasketed]
[NEMA Type 1] MCC unit completely factory wired and tested with the AC drive controller unit.
PART 3: EXECUTION
3.01 Inspection
a. Verify that the location is ready to receive work and the dimensions are as indicated.
b. Do not install the AC drive controller unit until the building environment can be maintained within the
service conditions required by the manufacturer.
3.02 Protection
a. Before and during the installation, the AC drive controller unit shall be protected from site
contaminants.
3.03 Installation
a. Installation shall be in compliance with the manufacturer’s instructions, drawings, and
recommendations.
b. The AC drive controller unit manufacturer shall provide a factory-certified technical r epresentativ e to
supervise the contractor’s installation, testing, and start-up of the AC drive controller unit(s)
furnished under this specification for a maximum total of [_____] days.
3.04 Training
a. An on-site training course of [_____] training days shall be provided by a representative of the AC
drive controller unit manufacturer to plant and/or maintenance personnel , and quot ed as a se parate
line item.