Attachment 3 - Specifications 20 05 14 VFD System.pdf

NBAF NBAF DESIGN PARTNERSHIP

LGL07C00004 800620.001

GMP-3, Final Record Documents 04/29/2022

VARIABLE FREQUENCY DRIVE (VFD) SYSTEM

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SECTION 20 05 14 -VARIABLE FREQUENCY DRIVE (VFD) SYSTEM

PART 1 - GENERAL

1.1 RELATED WORK

A. Section 20 05 13 - Motors

B. Section 23 21 23 - Pumps

C. Section 23 34 00 - Fans

D. Section 23 60 00 - Primary Cooling Equipment

E. Section 23 73 13 - Packaged Air Handling Units

F. Section 25 09 01 - Control Systems Integration

G. Section 25 09 93 - Control Sequences

H. Section 26 28 16 - Enclosed Switches and Circuit Breakers

I. Section 26 29 13 - Enclosed Controllers

1.2 SYSTEM DESCRIPTION

A. Provide Variable Frequency Drives (VFD) for each pump, fan or other driven equipment sized to accommodate motors shown on drawings or schedules. All VFD's shall be from same manufacturer.

B. VFD manufacturer shall review driven equipment and motors for VFD compatibility. Submit written statement from manufacturer of driven equipment along with VFD shop drawing submittals, indicating verification of compatibility.

C. CMc shall verify distance from motors to VFD's. VFD manufacturer shall provide sufficient equipment to assure proper operation and to avoid premature motor failure.

D. VFD manufacturer shall provide filter equipment as necessary to limit voltage transient ring wave stress placed on stator windings to withstand rating value of motors supplied per Section 20 05 13 - Motors.

E. VFD shall vary speed of its respective fan, pump or other driven equipment motor in response to either 4-20 mA or 0-10 VDC control signal provided by Control CMc.

F. VFD system shall consist of the following:

1. Variable frequency drive with harmonic mitigation

2. UL Listed disconnect device

3. Electrical noise attenuation device as required to meet electrical noise criteria.

4. Motor starter for bypass mode operation with VFD/OFF/BYPASS selector and drive input and output isolation contactors where VFD bypass starters are specified.

5. Integral Line reactor

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6. Step-up or step-down isolation transformer as noted

7. External Line reactor as noted

8. Harmonic Filter as specified

9. Long Lead Filter as specified

1.3 QUALIFICATIONS

A. VFD system shall be furnished by a manufacturer with at least 5 yrs experience in design, construction and application of VFD.

1.4 SUBMITTALS

A. Shop Drawings for each VFD system including, but not limited to, the following:

1. Manufacturer's name

2. Identification of system components

3. Type of enclosure, front elevation and plan view, equipment weight, conduit access locations

4. Capacities/ratings

5. Warranty

6. System wiring and block diagram showing system components

7. Performance, control and protection data with specified features clearly shown

8. Operating and monitoring devices with specified features clearly indicated

9. Start-up operation, maintenance, spare parts, and field tests

10. Manufacturer's installation instructions

11. Other appropriate data

12. Variations from this Specification

B. After quality assurance tests are complete, submit written certification that drive and components have passed factory quality assurance tests.

C. Submit calculations indicating conformance with electrical noise and THD criteria specified. Refer to Electrical Documents for information regarding electrical building distribution system.

D. Submit calculations indicating conformance with THD criteria specified at the point of common coupling (PCC). Refer to Electrical Documents for information regarding electrical building distribution system. All VFDs employed for use on this project including those provided under other specification sections shall be modeled in a single study. Calculation submitted without all drives will be rejected.

Obtain demand load calculations from electrical drawings for entry into calculation for each PCC. At a minimum, provide studies at each PCC for operational modes as follows:

1. Tie breaker open, all motors (including standby) operating at full load.

2. Tie breaker open, all motors (including standby) operating at partial load.

Partial load equates to load at which harmonic filter capacitors are disengaged to prevent leading power factor (see Section 2.2).

3. Tie breaker closed with opposite main open, all motors (including standby) on both sides of the tie operating at full load.

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4. Tie breaker closed with opposite main open, all motors (including standby) operating at partial load. Partial load equates to load at which harmonic filter capacitors are disengaged to prevent leading power factor (see Section 2.2).

E. Submit product and performance data on electrical noise attenuation device.

1.5 HARMONIC CONTROL IN ELECTRICAL POWER SYSTEMS

A. Variable frequency drives (VFD) are specified to meet harmonic distortion limits specified in ANSI/IEEE Standard 519-1992, Recommended Practices and

Requirements for Harmonic Control in Electrical Power Systems, based on the use of numerous drives simultaneously within the building and with the following criteria:

1. Low-voltage system classification and distortion limits: Special Application – Hospitals.

2. Point of common coupling (PCC): Secondary distribution bus (480Y/277V) of unit substations.

3. Total Harmonic Distortion (THD) Limit, Voltage: 3.0%.

4. Total Demand Distortion (TDD) Limit, Current: 5.0% with short circuit ratio

<20.

5. Individual Harmonic Order Limits, Current: Table 10-3 in ANSI/IEEE 519 for short circuit ratio<20.

6. The service transformers for this application shall not be subjected to harmonic currents in excess of 5% of transformer rated current in accordance with ANSI/IEEE Standard 519-1992, paragraph 10.4.1.

1.6 ELECTRICAL NOISE CRITERIA

A. VFD manufacturer shall perform harmonic analysis at the all points of common coupling (PCC) to define submittals that compliance to IEEE-519-1992, Special Category, is attained. Analysis shall include electrical one line drawing defining resistance and impedance of each wire run and transformer leading to each VFD.

Analysis shall be computer generated and perform Fourier analysis of the system.

Results shall list current and voltage amplitudes of all harmonics up to 50th level at input of distribution transformer. A summary shall detail percent total harmonic distortion for voltage and total demand distortion for current. Study shall assume maximum transformer loading of 100% of nameplate value.

B. Analysis shall include VFDs specified in all specification sections including those within packaged systems.

C. Refer to mechanical schedules for drive type of each VFD.

1.7 START-UP OPERATION AND MAINTENANCE DATA

A. Manufacturer shall provide services of factory trained engineer or technician to approve installation; start-up test and adjust for proper operation; and instruct and train Government's representative in operation and maintenance of VFD systems. Provide minimum of 8 hrs of Government training for VFD system.

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B. Documentation of power quality compliance shall be part of the start-up and commissioning services by the VFD supplier. Actual job site measurement testing shall be conducted at full load and documented in the startup report, prefunctional commissioning forms, and O&M manuals. Harmonic measuring equipment utilized for certification shall carry a current calibration certificate. The final test report shall be reviewed and compliance certification stamped by a licensed professional engineer. Text and graphical data shall be supplied showing voltage and current waveforms, THD and individual harmonic spectrum analysis in compliance with the above standards. Testing shall be conducted at each drive and at each PCC.

Testing at each PCC shall be conducted for operational modes as described in section 1.5.

C. Should drive be deficient, drive manufacturer shall be required to make changes necessary to bring units into compliance with specified performance requirements.

Cost of changes and retest shall be borne by drive manufacturer.

D. Upon completion of this service, submit a report signed by manufacturer's service representative, including start-up and test log.

E. Manufacturer shall include additional 2 yr (total 3 yrs) warranty for VFD system, covering parts, labor and travel expenses.

1.8 QUALITY ASSURANCE

A. The work of this section has been identified by the design team as a Level q3 or q4 quality level element. These elements are critical to the success of the project as identified in the Quality Management Plan. Refer to Section 01 40 00 for a complete definition of these levels and the portions of the project affected by these requirements.

1. All submittals identified within this section will be identified as a q3 or q4 element.

2. Deviations from the Contract Documents with q3 or q4 elements will be deemed unacceptable.

PART 2 - PRODUCTS

2.1 MANUFACTURER

A. Manufacturers: ABB, Allen Bradley/Rockwell Automation, Cutler-Hammer, Danfoss Graham, General Electric, Yaskawa (MagneTek), Reliance/Rockwell

Automation, or Toshiba

2.2 HARMONIC MITIGATION

A. Drive technology described in this section shall be the minimum configuration and shall be adjusted as needed to meet harmonic criteria described in Section 1.6.

B. Drives 75 hp and larger shall incorporate one of the following harmonic mitigation features:

1. Ultra-low harmonic drives: ABB ACS800 Series or equal from other listed manufacturers.

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2. 18-pulse technology with integral 5% line reactor and external 5% line reactor.

C. Drives smaller than 75 hp: 6-pulse technology with integral 5% line reactor and harmonic filter.

2.3 FABRICATION

A. VFD shall be variable torque, solid state, microprocessor based control, modular design for standard induction AC motor.

B. Unless otherwise indicated, all VFD components, including the power service disconnect, drive, integral line reactor, external line reactor, by-pass starter, output LC filter, output dv/dt filter, etc, shall be factory mounted and wired in a single NEMA 1 enclosure with lock.

C. Circuitry shall be plug-in, plug-out modular. Printed circuit boards shall have protective coating to reduce corrosion.

D. Unit shall conform to NEMA and NEC standards and be UL or ETL Listed. Control circuitry shall be electrically isolated from power circuitry. Entire assembly panel shall have UL or ETL equivalent panel sticker.

E. Invertor section shall be pulse width modulated (PWM) design and most current insulated gate bipolar transistors (IGBTs) technology.

2.4 PERFORMANCE REQUIREMENTS

A. Input: 460 (+ 10%, - 15%) VAC, 3-phase, 60 (± 2) Hz

B. Output: 460 VAC, 3-phase, 10 to 60 Hz

C. Operating Environment Conditions: Ambient 0 to 40°C temperature, relative humidity up to 95% non-condensing.

D. Linear acceleration and deceleration adjustable from 5 to 60 seconds. Provide adjustable v/Hz ratio and low speed boost features.

E. Output Current Rating: Continuous full load output current rating of drive shall not be less than that listed for motor of equivalent horsepower in NEC table 430-

150.

F. Drive overload capacity to be minimum 110% of motor FLA based on NEC ratings for one minute.

G. Time to Shutdown: Inversely proportional to square of overload current (t = k/I2).

H. Motor Regeneration Protection: Unit shall have capacity of dissipating regeneration energy without damage to or shutdown of drive. Unit shall be capable of starting into rotating load.

I. Output Frequency Stability: ± 0.5% of base frequency in 24 hrs throughout range of rated operating conditions.

J. Output Voltage Regulation: ± 2% of maximum rated output voltage.

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K. Output voltage rise time shall be no faster than 1000 V/micro sec measured at the motor terminals. Provide dv/dt output filter for excessive motor lead length between VFD and motor exceeding 75 feet for motors below 25 HP and 100 feet for all other motors.

L. Power Loss Ride-Through: 3 cycles or 50 milliseconds.

M. Linearity (speed reference to output frequency): ± 1.0%

N. Input Power Factor: Minimum of 0.95 regardless of speed and load.

O. Minimum drive efficiency as percent of input power shall be as follows:

Percent Load Frequency (Hz)

60 50 30 15

100 97 96 95 90

75 97 96 94 90

50 97 96 94 90

25 96 95 91 84

2.5 CONTROL FEATURES

A. VFD speed control circuit shall accept either 4-20 mA DC or 0-10 VDC isolated ungrounded transmitter signal in automatic mode and from manual speed potentiometer in manual mode.

B. Provide adjustable minimum and maximum speed settings (0 - 100%) for both auto and manual mode. Initial minimum setting shall be 25%.

C. Provide adjustable automatic reset for fault trips, except short circuit type faults.

After selected number of unsuccessful restart attempts, drive shall be shut down.

Number of restart attempts and time interval between resets shall be selective.

D. When unit shuts down due to power outage, unit shall be capable of being restarted manually or automatically.

E. VFD shall be capable of starting into rotating loads spinning in any direction and accelerate or decelerate to the required control frequency without stopping or going into minimum speed first.

F. Provide critical frequency avoidance circuit with at least 3 field adjustable bands to avoid operation at speeds, which cause excessive vibration in driven equipment.

G. Provide isolated ungrounded output signal to indicate drive percent of speed or drive frequency.

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H. Provide damper control circuit to open control dampers during start-up sequence of the drive. Also provide interlock with speed command to prevent operating the drive at greater than minimum speed (adjustable) until damper is verified open via end switches. Control damper circuit shall be active in VFD and BYPASS STARTER mode. Damper control logic shall require damper open command and proof via end switches prior to starting across the line in bypass mode.

I. Provide MANUAL/AUTO switch for each VFD. In the MANUAL mode the driven equipment shall start and run continuously at a speed manually set on the drive unless a safety device trips. In the AUTO position, the Building Automation

System (BAS) shall control the drive/driven equipment.

J. Provide VFD/OFF/BYPASS selector switch to allow the VFD to operate in normal frequency control mode or constant speed bypass mode. In VFD mode, motor control shall be via the VFD. In OFF mode, motor and drive shall be off. In BYPASS mode, motor control shall be via the bypass starter.

K. Provide control for automatically switching from VFD to by-pass line through adjustable time delay relay or equivalent protection whenever VFD shuts down automatically.

2.6 COORDINATION WITH BUILDING AUTOMATION SYSTEM (BAS)

A. Furnish each VFD with BACnet MS/TP digital communication bus card for BAS use.

Coordinate with Control CMc for specific interface requirement. Final connection shall not require any additional intermediate gateway devices to provide throughput of data. The following data shall be provided at a minimum:

1. Fault Condition

2. Speed

3. VFD Manual/Auto Status

4. Power (kW)

B. Provide contacts (1 NO and 1 NC contact) for remote control of start/stop function for VFD mode.

C. Provide input terminals for wiring speed signal from BAS controller.

D. Provide contacts for remote indication of VFD/OFF/BYPASS switch position.

2.7 PROTECTION FEATURES

A. Power circuits shall be protected by, electronic protection circuits. Electronic protection circuits shall provide orderly shutdown without blowing fuses and prevent component loss under the following abnormal conditions.

1. Instantaneous overcurrent and over voltage trip of output

2. Solid state protective circuit shall provide NEC motor running overload protection tested in accordance with UL Standard 991

3. Power line overvoltage or undervoltage

4. Phase sequence detection or insensitivity to incoming power phase sequence

5. Single and 3-phase short circuit protection

6. Control circuit malfunction

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7. Overtemperature

8. Ground fault for all 3 phases

B. VFD shall protect itself from damage due to phase-to-phase or phase-to-ground faults without fuse blowing or use of isolation transformers. VFD’s, which require isolation transformers to provide ground fault protection, are not acceptable.

C. In addition, provide the following protection features.

1. Input line-to-line and line-to-ground transient protection up to 3000 V

2. Control circuit transformer fusing

3. Grounded control chassis

4. Diagnostic indication

5. One set of spare fuses for each type used in drive for each VFD

D. Interlock VFD control circuits with driven motor's disconnect switches where such motor disconnect switches are provided. Disconnecting on-line motor shall shut down VFD. VFD shall restart upon reconnection of motor.

E. VFD shall employ adjustable torque limit control, which shall override speed command and decrease frequency while maintaining correct volts/hertz ratio whenever load level surpasses VFD design level or set point.

2.8 OPERATING AND MONITORING DEVICES

A. The following functionality shall be provided and may be controlled via touchscreen/keypad:

1. Door interlock to disconnect VFD input power

2. Manual stop/start device

3. Operating mode selector device marked "Manual-Off-Automatic"

4. Manual speed control potentiometer

5. Power on indication

6. Drive run indication

7. Drive fault indication with testable feature

8. Fault reset device

B. Speed indicating meter or digital indication (0 - 100%) calibrated in percent speed or frequency meter with 0 to 90 Hz scale to indicate motor speed.

C. Integral digital programming and operating display which shows Hz, Percent

Output Current, Output Voltage, Percent Output Power, Operating Parameters and their values, and Diagnostic Fault Codes. In addition, Keypads shall be incorporated to facilitate digital programming of drive adjustments. Analog potentiometer adjustments are not acceptable.

D. Provision shall be included to provide selectable programming security by inhibiting program parameter changes with internal dip switch setting or with password security.

E. Control shall incorporate microprocessors for operator interface, diagnostics, and fault managements, and power management.

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F. Optional DOS-based programming software, which includes provision for serial communication with drive, shall be available for shipment at time of equipment order placement.

G. Fault buffers to sequentially store last 4 faults. Parameter and fault information to be stored in non-volatile memory.

H. VFD with Manual Bypass Starter:

1. Manual selector switch to select power through VFD or bypass line with label marked "VFD/OFF/BYPASS".

2. Mechanically- and electrically-interlocked VFD/BYPASS contactors with padlocking capability on input side of VFD and bypass starter. Interlock shall be accomplished such that shorting together of any 2 control circuit points cannot cause non-selected device to be energized. Provide mechanically-and electrically-interlocked device that connects only output of selected starting device (VFD or bypass starter) to VFD system output lug. Single shorting of any 2 control circuit points shall not cause both VFD and bypass starter outputs to be interconnected.

2.9 QUALITY ASSURANCE TESTS

A. Complete drive assembly shall be factory tested with actual AC induction motor, 100% load and temperature cycled within environment chamber at 40°C (104°F).

Documentation of test shall be furnished to verify successful completion of test at

Engineer's request.

2.10 DISCONNECT DEVICE

A. Provide integral switch to disconnect incoming electrical power to units.

Disconnect device shall be UL Listed device of the following:

1. Motor circuit switch: horsepower rated

2. Enclosed molded case breaker; ampere rated and providing over current protection

3. Molded case switch; ampere rated enclosed switch with or without over current protection

4. Rotary switch: with or without fuser

B. Assembly shall have an interrupting rating not less than that of the upstream overcurrent device as shown on electrical drawings. Minimum rating shall be 65kA.

C. Disconnect shall be capable of being padlocked in OFF position and complying with

OSHA Requirements. Operating handle shall indicate whether switch is “ON” or

“OFF”.

D. Switch shall have dual cover interlock to prevent unauthorized opening of switch door when handle is in “ON” position and to prevent closing of switch mechanism with door open. Provide defeater mechanism to defeat the interlock for user required access.

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2.11 MOTOR CONTROL EQUIPMENT (BYPASS STARTERS)

A. Bypass starter shall be NEMA or IEC Rated device of the following:

1. Electromechanical across-the-line starter with solid state overload protection for 50 hp or smaller.

2. Solid-state reduced voltage starter consisting of SCR based power section, logic control board and solid state overload protection for 60 hp or larger.

3. Reduced voltage auto transformer - electromechanical starter with solid-state overload protection for 60 hp or larger.

2.12 LINE REACTORS

A. Series line reactors shall be designed for harmonic filtering service and shall be

UL component recognized. Construction shall be copper wire wound on steel cores. Inductors shall be 3-phase. Series line reactors shall be sized at 5% impedance and appropriately for total connected load. Design maximum temperature rise for inductors shall be 115°C.

B. Core shall be made of laminated grain oriented electrical steel (grade M6 or better). Brackets shall be ASTM structural steel or structural aluminum. Coils shall be wedged in place and core locked in place using vertical ties or rods.

C. Windings shall be copper wire, MW35C (round) or MW36C (rectangular) or copper foil. Terminations shall be tin plated copper alloy ring lugs, UL recognized terminal blocks, or solid copper bus. Terminations shall be pressure crimped or TIG welded to windings. Sheet insulation shall be DuPont Nomex 410 of thickness meeting UL insulation systems.

D. Inductors shall be double impregnated (vacuum/pressure impregnate and bake followed by varnish dip and bake). Insulation systems shall be rated Class H (180°C), 600 V. Inductors shall be Hi-Pot tested (2500 V, 60 Hz, 1 minute) line-to-line and line-to-ground.

E. Inductors shall be air-gapped to avoid saturation. Inductance shall be measured under full load and shall be within ± 5% of design value.

F. Line reactor shall be included integral to drive enclosure.

1. Where mounting line reactor in VFD enclosure is not possible, enclosure shall be steel with enamel finish and no knockouts. Enclosure shall match construction of VFD enclosure and shall have hinged lockable cover. Screened openings shall be provided for enclosure ventilation. Enclosure shall be built with integral mounting brackets for platform or wall mounting. Coordinate location with other trades.

2.13 HARMONIC FILTERS

A. Harmonic filter shall contain a tuned circuit designed to remove harmonics generated by a VFD in a power distribution system while improving the system power-factor. The Harmonic filter shall be HARMONICGUARD SERIES DRIVE- APPLIED HARMONIC FILTER (hereafter called an "HG7") manufactured by TCI

(Trans-Coil. Inc. – Milwaukee, WI).

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B. The harmonic filter shall consist of inductive and capacitive elements arranged in a series configuration and tuned to resonate just below the harmonic frequency for which it is designed to filter. The harmonic filter shall have its minimum impedance at the tuning frequency. At frequencies above the tuning frequency, the harmonic filter impedance shall be inductive. The inductance in the harmonic filter, combined with the series line reactor, shall act to limit current surges between the capacitor and other plant electrical equipment and shall minimize the possibility of equipment or capacitor damage due to such surges.

C. The fusing, tuning reactor and capacitor shall be in parallel with the VFD. The VFD shall remain operational in the event of a failure of the capacitors or other condition causing the fuses to open. The voltage regulation at the VFD terminals and attributable to the filter shall not exceed 5%. Filters with greater than 10% voltage drop, and/or filters that have capacitors in series with the VFD, are not acceptable.

D. The harmonic filter shall be tuned to 4.7 times the fundamental frequency. The harmonic shall be listed by Underwriters Laboratories as an Industrial Control Panel as governed by UL508A.

E. Harmonic filter shall be included integral to drive enclosure.

1. Where mounting harmonic filter in VFD enclosure is not possible, enclosure shall be steel with enamel finish and no knockouts. Enclosure shall match construction of VFD enclosure and shall have hinged lockable cover. Screened openings shall be provided for enclosure ventilation. Enclosure shall be built with integral mounting brackets for platform or wall mounting. Coordinate location with other trades.

F. Harmonic filters shall include an integral contactor in-line with the filter capacitor such that the capacitor can be removed from the filter circuit.

G. Drives shall be programmed and wired by drive manufacturer to disengage harmonic filter capacitor should operational scenarios (i.e. lightly loaded distribution system) create a power system leading power factor. VFD and filter manufacturers shall be responsible for determining set point at which filter capacitors are disengaged. Disengaging capacitors shall not cause harmonic profile to exceed limits specified in Section 1.6.

2.14 OUTPUT LC FILTER

A. Output LC filter shall consist of gapped, three phase, iron core inductor; AC-rated polypropylene capacitors; and wire-wound resistors. Filter shall be rated for application at maximum fundamental system frequency of 60 Hz at nominal system voltages up to 600 V. Filter shall operate at maximum carrier frequency of 8 kHz at 40% of fundamental voltage. Ambient temperature of operation shall be 40°C.

B. Three phase inductors shall be designed for harmonic filtering service and for slowing rate of rapid current changes. Inductors shall be UL component-recognized and shall be built to comply with UL 508A Standard. Construction shall be of copper wire wound on magnetic grade steel. Inductors shall be sized appropriately for total connected load. Design maximum temperature rise for reactors shall be 115°C at rated current.

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C. Core shall be made of laminated grain-oriented electrical steel (grade M6 or better). Brackets shall be ASTM structural steel or structural aluminum. Coils shall be wedged in place and core shall be locked in place using vertical ties or rods.

D. Windings shall consist of copper wire or of copper foil. Terminations shall be copper alloy ring lugs, UL-recognized terminal blocks, or solid copper bus. Sheet insulation shall be DuPont Nomex 410 of thickness as required for UL insulation systems.

E. Inductors shall be air-gapped to control saturation. Inductance shall be measured under full load and shall be within 10% of design value.

F. Completed inductors shall be impregnated with 100% solid epoxy resin.

Insulation varnish systems shall be rated Class H (180°C), 600 V.

G. Filter shall be housed internal to drive enclosure.

2.15 DV/DT OUTPUT FILTER

A. Output filter for excessive motor lead length between VFD and motor exceeding 75 feet for motors below 25 HP and 100 feet for all other motors.

B. Filter manufactured by TCI (Trans-Coil. Inc. – Milwaukee, WI), part number filter

KLCxxBE, where xx is equal to or greater than the motor full amps.

C. Locate filter within ten (wire) feet from the VFD that is services.

D. Set the VFD carrier frequency to 8 kHz or below and operating frequency to 60 Hz or below

2.16 SPARE PARTS

A. Additional enclosure cooling fan for each different type of drive.

B. Additional key pad/touch screen for each different type of drive.

PART 3 - EXECUTION

3.1 INSPECTION

A. Visually inspect equipment and components at time of delivery. Submit report to Engineer with list of items or deficiencies to be corrected.

3.2 PROTECTION

A. Protect VFD cabinets from dust/dirt during storage and operation until turned over to Government.

B. If VFDs are not furnished with internal air filter racks, provide temporary filter media to protect VFD cabinets and replace filter media as required.

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3.3 INSTALLATION

A. Install VFD system in accordance with details, approved Shop Drawings and manufacturer's instructions and recommendations.

B. Provide field low voltage wiring of VFD system components. Provide field interconnecting wiring between VFD and by-pass starter if bypass starter is specified and the wiring is not installed at factory. Install wiring in metal conduit and in accordance with Electrical sections of this Specification and applicable Electrical Code.

C. Provide control wiring between interlocks in VFD control circuits and driven motor's disconnect switches, where such motor disconnect switches are provided.

D. Do not connect ground from one unit to another unit's cabinet.

E. Use separate conduits for incoming and outgoing power conductors from each unit.

F. Use separate conduit for control wiring for each unit. Control wiring shall not occupy same conduit as power wiring.

G. Use minimum 18 ga shielded wiring with ground for control wiring.

H. Install floor mounted drives on 3-1/2" high concrete housekeeping pad.

3.4 START UP

A. Perform start-up of VFD in accordance with procedures as defined by manufacturer for proper operation.

B. Adjust critical frequency avoidance feature to step over frequencies which cause excessive vibration in driven equipment.

3.5 TESTING

A. Provided testing as described in paragraph 1.3.

B. Adjust or replace equipment as needed to comply with manufacturer's specifications and resubmit corrected test reports.

END OF SECTION