VTAC 9 AC Drive Guide Specification
Adjustable Frequency Drives with Bypass
1 – 100 Hp @ 208V AC
1 – 200 Hp @ 480V AC
PART 1 – GENERAL
1.01
Quality Assurance
A. The manufacturer shall have minimum 5 years experience in the design and manufacture of Variable
Frequency Drives (VFDs).
B. The VFD and all associated equipment shall be UL Listed according to UL 508C – Power Conversion
Equipment. As verification, a UL label shall be attached on the enclosure.
C. The VFD shall be UL approved for mounting in plenums and compartments handling conditioned air.
D. The VFD shall be designed, constructed and tested in accordance with UL, CSA, NEMA, and NEC
standards.
1.02
Submittals
A. [ __ ] submittal packages shall be furnished for Engineers’ approval prior to factory assembly of AC
drives.
B. Submittals shall include:
1. Outline Drawings
2. Schematic Drawings
3. Interconnect Drawings
PART 2 – PRODUCT
2.01
Manufacturers
A. The VFD shall be provided by Rockwell Automation, or prior approved equal.
B. Substitutions must be submitted in writing three (3) weeks prior to original bid date with supporting
documentation demonstrating that the alternative manufacturer meets all aspects of the specification
herein.
2.02
General Requirements
A. The VFD shall convert the input AC main power to an adjustable frequency and voltage as defined in
the following sections.
B. The VFD shall be listed and labeled as a complete unit and shall include all accessories and
requirements as described in this section.
2.03
Environmental Ratings
A. Storage ambient temperature range: -40 to 70°C (-40 to 158°F).
B. Ambient temperature operating range: 0 to 40°C (32 to 104°F).
C. Relative humidity range: 5% to 95%, non-condensing.
D. Operating elevation: 1000 Meters (3,300ft).
E. Shock: 15G peak for 11ms duration.
F. Vibration: 0.152 mm (0.006 inches) displacement, 1G peak.
G. Meet seismic requirements of the 2003 International Building Code as specified by AC156.
2.04
2.05
Motor Data
A. The AC drive shall be sized to operate the following AC motor:
1. Motor horsepower [ __ ].
2. Motor full load ampere [ __ ].
3. Motor rpm will be [900] [1200] [1800] [3600] at 60Hz.
4. Motor voltage will be [208] [460] VAC.
5. Motor service factor will be [1.00] [1.15] [1.25].
Application Data
A. The AC drive shall be sized to operate a variable torque load.
B. The speed range shall be from a minimum speed of 1.0 Hz to a maximum speed of 60 Hz.
2.06
Construction
A. The VFD shall be rated IP20/NEMA Type 1.
B. Conduit knockouts shall be provided for bottom cable entry.
C. All VFDs shall be wall mountable.
2.07
Ratings
A. The VFD shall be designed to operate from an input voltage of [208V AC ±10%] [480V AC ±10%].
B. AC frequency: [50Hz ±5%] [60Hz ±5%]
C. Current overload rating:
1. 110% of rated current for 60 seconds
2. 150% of rated current for 3 seconds
D. Speed regulation: ±0.5% of base speed across a 40:1 speed range.
2.08
Protection
A. The VFD shall be protected against short circuits, between output phases and to ground.
B. The VFD shall have under-voltage and over-voltage protection.
C. The VFD shall provide class 10 motor overload protection investigated by UL, to comply with N.E.C.
Article 430.
D. The VFD shall be able to sense a loss of load and signal a fault.
E. If the input analog reference is lost, this shall cause a warning to be issued and the user shall have the
option of pre-selecting either (1) stopping and displaying the fault, (2) running at programmable preset
speed, (3) running at min or max frequency or (4) holding last frequency command.
2.09
Integral Functions
A. Process PI Control:
1. PI regulator shall be standard in the VFD. This allows a pressure or flow signal to be connected to
the VFD for closed loop control.
2. The PI setpoint shall be adjustable from the Programming Terminal, Analog Inputs or
Communication Networks.
B. Skip Frequencies / Bands:
1. The VFD shall have at minimum (3) programmable set points that lock out continuous operation at
frequencies, which may produce mechanical resonance.
2. The setpoints shall have an adjustable bandwidth.
C. Flying Start:
1. The VFD shall be capable of determining the speed and direction of a spinning motor and adjust its
output to “pick-up” the motor at the rotating speed.
D. Start At Power Up:
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1.
The VFD shall have a programmable restart function to automatically restart the equipment after
restoration of power after an outage.
2. A maintained 2-wire start input shall be necessary for this function.
E. Sleep / Wake Mode:
1. The VFD shall have the capability to use an analog input or PI output as a start – stop command.
This input can be a separate input or also used as the speed reference. Signal level below the
“sleep” level acts as a Stop Command and a signal level above the “Wake” level acts as a Start
Command.
2. Sleep / Wake time and level shall be programmable.
F. Auto Restart
1. The VFD shall have the capability to attempt (9) restarts following a fault condition before locking
out and requiring manual intervention.
2. The time between restarts shall be adjustable.
2.10
Programming Terminal
A. The VFD shall include a removable programming terminal.
B. The programming terminal shall have at minimum an alphanumerical LCD display with LED backlight.
C. Digital speed control buttons shall be provided. Potentiometers are not acceptable.
D. Hand and Auto button to enable and release manual reference control.
E. Text support in multiple languages, including but not limited to English, German, French, Italian,
Spanish and Portuguese.
F. The programming terminal shall enable icon-based drive programming procedures.
2.11
Control Interface
A. Analog Inputs:
1. (1) Isolated analog input (-10 to 10V or 4 to 20mA), user selectable.
2. (1) Non-isolated analog input (0 to 10V or 4 to 20mA), user selectable.
3. Analog I/O must have 10 bit resolution or better.
B. Analog Outputs:
1. (1) Analog output (0 to 10V).
2. Analog I/O must have 10 bit resolution or better.
C. Digital Inputs:
1. (6) Digital inputs (24V DC), user programmable.
2. Inputs must be configurable as sink or source.
3. The VFD shall have a dedicated digital input for a Purge function. Purge can occur and should be
operational at any time whether the drive is running or stopped.
4. The VFD shall have (2) dedicated digital inputs for Customer Interlocks:
a. One interlock will not record a fault and permit running after external condition is met. Purge
input will override this interlock.
b. One interlock will cause a drive fault and require control system to reset prior to returning to
ready condition. This input will always be active even during Purge.
D. Relay Outputs:
1. (2) Relay outputs, form C (1 N.O. and 1 N.C.), user programmable.
2. Both relays must be programmable for a minimum of 16 different combinations including Drive
Ready, At Frequency, Motor Running, Motor Overload, Fault and others.
2.12
Internal Adjustments
Acceleration time shall be adjustable from 0.1 to 3600 seconds.
Deceleration time shall be adjustable from 0.1 to 3600 seconds.
(4) preset speeds shall be provided.
VFD shall have an adjustable PWM frequency to allow tuning the VFD to the motor.
A.
B.
C.
D.
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2.13
Communication
A. A single RS-485 communication option card shall allow network protocol selection using dip-switches to
allow direct connection from the drive to:
1. Metasys N2
2. Siemens Building Technologies FLN-P1
3. Modbus RTU
B. Optional LonWorks communication card shall be available.
C. Optional BACnet communication card shall be available.
2.14
Bypass Package
A. Door-interlocked Main Input Disconnect shall mount within the standard NEMA 1 enclosure for positive
power disconnect of the VFD. It shall have the capability for door padlocking.
B. Input line fuses shall provide protection for the input rectification circuit using Class J fuses. The series
interrupting rating of the VFD and fuses shall be a minimum of 100,000 AIC.
C. A complete three contactor bypass shall be provided to allow the motor to be safely transferred from
VFD output to the AC line or from the AC line to the VFD, while the motor is at zero speed. The
contactor bypass shall be electrically interlocked. The contactors shall be IEC rated and have the
following functionality:
1. Drive Input Contactor shall open and close input to the drive.
2. Drive Output Contactor shall open and close the connection between the drive and motor.
3. Bypass Contactor shall open and close the connection to line start the motor.
D. A three-position Drive/Drive Test/Bypass switch on the bypass operator interface shall have the
following functionality:
1. In Drive Mode, the drive input contactor and the drive output contactor shall be closed to allow
operation of the motor by the drive.
2. In Drive Test Mode, the drive input contactor shall be closed to keep the power on to the drive. The
drive output contactor and bypass contactor shall remain open. This shall enable the user to test
the drive before running the motor. A jumper shall be added to test the drive while the motor is
running in bypass and must be field installed to alert operators of this condition.
3. In Bypass Mode, the drive input and the drive output contactor will be open to isolate the drive.
The bypass contactor will be closed to allow the motor to run directly from the AC line.
E. Bypass motor overload protection shall be provided by bimetallic Class 20 Smart Motor Protection
adjustable overload relay.
F. A three-position Hand/Off/Auto switch on the bypass operator interface shall allow the user to:
1. Transfer the control source (Start/Stop) to the drive keypad in Hand Mode.
2. Stop the motor in Off Mode.
3. Transfer the control source (Start/Stop) to the drive’s terminal block in Auto Mode
G. The operator interface on the bypass option box shall have the following indicating LEDs:
1. Ready (green)
2. Interlock Open (yellow)
3. Bypass Run (green)
4. Bypass Trip (red)
5. Purge (yellow)
6. Drive output enable (green)
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PART 3 – EXECUTION
3.01
Installation
A. Installation shall be in compliance with manufacturer’s instructions, drawings and recommendations.
B. Installation shall be the responsibility of the mechanical contractor.
3.02
Start-up
A. Certified factory start-up shall be provided for each VFD provided.
B. Service engineers shall be employed by the manufacturer or be certified by the manufacturer and
provide start-up services including physical inspection of drive and connected wiring and final
adjustments to meet specified performance requirements.
3.03
Warranty
A. Warranty shall be 24 months from the date of certified start-up, not to exceed 30 months from the date
of shipment
3.04
Product Support
A. Factory trained application engineering and service personnel that are familiar with the VFD products
offered shall be locally available.
Trademarks not belonging to Rockwell Automation are property of their respective company.
www.vtacdrives.com
VTAC Headquarters
Rockwell Automation, 6400 West Enterprise Drive, Mequon, Wisconsin 53092 USA, Tel: 262.512.8200
Publication 9VT-SR003A-EN-P – August 2006
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Copyright © 2006 Rockwell Automation, Inc.. All rights reserved. Printed in USA.