SECTION MOTORS AND VARIABLE FREQUENCY DRIVES

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1 PART 1 GENERAL 1.1 RELATED DOCUMENTS A. Related Sections: 1. Section Basic Mechanical Requirements. 2. Section Motors. 3. Section Hydronic Pumps. 4. Section Centrifugal Water Chillers. 5. Section Open Circuit Mechanical Draft Cooling Towers. 6. Section Modular Indoor Air Handling Units. 7. Section Packaged Outdoor Central Station Air Handling Units. 8. Section Rooftop Replacement Air Units. 9. Section Rooftop Evaporative Cooling Units. 10. Section Fan Coil Units. 11. Section Switchboards. 12. Section Panelboards. 1.2 SUMMARY A. Section includes three phase electric motors and variable frequency drives. 1.3 REFERENCES A. AFBMA 9 - Load Ratings and Fatigue Life for Ball Bearings. B. AFBMA 11 - Load Ratings and Fatigue Life for Roller Bearings. C. ANSI/IEEE Test Procedure for Polyphase Induction Motors and Generators. D. ANSI/NEMA MG 1 - Motors and Generators. E. ANSI/NFPA 70 - National Electrical Code. F. IEEE Std Guide for Harmonic Controls and Reactive Compensation of Static Power Converters. G. ANSI/UL Std Testing by Independent Laboratories. 1.4 SUBMITTALS A. Section Basic Mechanical Requirements: Submittals and Contract requirements. B. Submit factory test results verifying nominal efficiency and power factor for three phase motors larger than 20 horsepower. C. Submit manufacturer's installation instructions under provisions of General Conditions Sections. Page 1 of 6

2 1.5 OPERATION AND MAINTENANCE DATA A. Submit operation and maintenance data under provisions of General Conditions and Section Basic Mechanical Requirements and Section Basic Electrical Materials and Methods. B. Include assembly drawings, bearing data including replacement sizes, and lubrication instructions. 1.6 QUALIFICATIONS A. Manufacturer: Company specializing in manufacture of electric motors and variable frequency drives for HVAC use, and their accessories, with minimum three years documented product development, testing, and manufacturing experience. 1.7 REGULATORY REQUIREMENTS A. Conform to applicable electrical code. B. Conform to local energy code. 1.8 DELIVERY, STORAGE, AND HANDLING A. Protect motors and controllers stored on site from weather and moisture by maintaining factory covers and suitable weather-proof covering. For extended outdoor storage, remove motors from equipment and store separately. 1.9 WARRANTY A. Provide one year manufacturer's on-site labor and material warranty. B. Warranty: Include coverage for motors and variable frequency drives. PART 2 PRODUCTS 2.1 MANUFACTURERS A. Motors: U.S. Motors, Reliance, Baldor, or Marathon. B. Adjustable Frequency Controllers: Danfoss, VLT 4000, No Substitutions. 2.2 GENERAL CONSTRUCTION AND REQUIREMENTS A. Motors: Design for continuous operation in 40 degrees C environment, and for temperature rise in accordance with ANSI/NEMA MG 1 limits for insulation class, Service Factor, and motor enclosure type. Page 2 of 6

3 B. Design variable frequency drives for operation with the actual motor and driven pumps or fans. C. Visible Nameplate: Indicating motor horsepower, voltage, phase, cycles, RPM, full load amps, locked rotor amps, frame size, manufacturer's name and model number, Service Factor, Power Factor. D. Electrical Connection: Conduit connection boxes, threaded for conduit. For fractional horsepower motors where connection is made directly, provide conduit connection in end frame. 2.3 THREE PHASE POWER - SQUIRREL CAGE MOTORS A. Starting Torque: Between one and one and one-half times full load torque. B. Starting Current: Six times full load current. C. Power Output, Locked Rotor Torque, Breakdown or Pullout Torque: NEMA Design B characteristics. D. Design, Construction, Testing, and Performance: Conform to ANSI/NEMA MG 1 for Design B motors. E. Insulation System: NEMA Class B or better. F. Testing Procedure: In accordance with ANSI/IEEE 112, Test Method B. Load test motors to determine freedom from electrical or mechanical defects and compliance with performance data. G. Motor Frames: NEMA standard T-frames of steel, aluminum, or cast iron with end brackets of cast iron or aluminum with steel inserts. H. Bearings: Grease lubricated anti-friction ball bearings with housings equipped with plugged provision for relubrication, rated for minimum AFBMA 9, L-10 life of 20,000 hours. Calculate bearing load with NEMA minimum V-belt pulley with belt center line at end of NEMA standard shaft extension. Stamp bearing sizes on nameplate. I. Sound Power Levels: To ANSI/NEMA MG 1. J. Nominal Efficiency: Meet or exceed values in Schedules at full load and rated voltage when tested in accordance with ANSI/IEEE 112. K. Nominal Power Factor: Meet or exceed values in Schedules at full load and rated voltage when tested in accordance with ANSI/IEEE 112. L. Motors shall deliver full nameplate horsepower without de-rating due to thermal Page 3 of 6

4 considerations when on variable frequency power. 2.4 VARIABLE FREQUENCY DRIVES (VFD) A. Variable Frequency Drive Systems shall be Danfoss VLT 4000 with Adaptable Package Unit. Variable Frequency Drive Systems shall be compatible with any standard NEMA B design 3- phase induction motor. Variable Frequency Drive Systems shall be sized to insure the motor full load amps do not exceed the controller continuous RMS amps. B. The adjustable frequency drive shall convert three-phase, 60 Hz utility power to adjustable voltage and frequency, three phase, AC power for motor speed motor control from 10% to 100% of the motor's 60 Hz speed. Input voltage shall be as specified on the drawings schedules. The input section of the drive shall include line filters, line reactors or isolation transformers as required to meet IEEE 519 for distortion levels of 3% or less. The variable frequency drives shall not interfere with sensitive electronic equipment that is fed from the same power distribution system. C. The output wave form shall be sine coded pulse width modulated. To eliminate acoustical noise, PWM drives shall have a minimum of 2500 pulses per sine. The VFD's input power factor shall be.95 or better at all operating speeds. Efficiency shall be 96% minimum from 0-100% load. To eliminate RFI and EMI, the drive shall comply with FCC rules and regulations, part 15, subpart "J". D. Solid State Ground Fault Protection shall be standard. Those manufacturers that cannot provide this as a standard feature must supply an external protector. Adaptive electronic motor overload protection shall be provided which shall protect both the motor and drive at all frequencies. Electronic thermal overload circuits which properly protect the motor only at full speed shall not be acceptable. The VFD shall sense the load and speed and shall recalibrate the thermal trip curve to insure low speed motor protection. The initial trip point shall be adjustable from at least % of the VFD amperage rating. E. Isolated control inputs shall be provided. The motor speed shall be directly proportional to 0-10 volt, 4-20 ma, and variable resistance signals. Fire alarm signal for control override to maximum speed at smoke control fans. F. Drive operation options shall be switch selectable and shall include at a minimum the following functions: 1. Automatic speed holding if control signal is lost at 80% of last speed command. 2. The VFD shall provide the following operational features: a. Speed search transfer. The VFD shall be able to start from bypass or fault trip into a spinning load without stopping the motor or creating a fault condition. The VFD shall match the motor's speed and then drive the motor to its proper speed. b. Adjustable current limit threshold. c. Multiple restart upon fault trip. d. Minimum 10:1 speed ratio. e. Individually adjustable acceleration and deceleration patterns, adjustable from seconds. Page 4 of 6

5 G. The VFD shall be suitable for installation and use under the following environmental conditions: 20 to 104ºF, 0-95% RH, non condensing. H. Fault Indication and Operation 1. The following fault conditions shall cause the VFD to shut-off (trip) and shall be annunciated by LED indicators on the control board. FU: Fuse Blown, OC: Instantaneous Overcurrent, OV: Overvoltage, UV: Undervoltage, OH: Overheat, EB: External Failure, CPF: Control Function Error, CFP-SEL: Control Function Selection Error, OL: Overload. 2. The VFD shall attempt to restart a minimum of 5 times after tripping on a fault. A dry contact on the VFD shall close after the fifth unsuccessful restart attempt. 3. The VFD shall be set by the manufacturer to prevent the possibility of overamperage on the motor in the associated drive. This feature shall be coordinated with the ATC Contractor and the Mechanical Contractor for the project. I. The VFD shall be equipped with a digital operator interface which shall allow the following functions: 1. Digital frequency indication on an LCD display. 2. Digital fault indication on the LCD display. Digital fault reset. Storage and operator initiated recall of the fault conditions in the sequence of occurrence. 3. Auto/Manual operation switch. 4. Digital speed control in 0.1 Hz increments. 5. Tracking of fault/failure history. 6. Display of frequency or RPM. 7. Self diagnostics. J. Where indicated, manual bypass shall provide all the circuitry necessary to safely transfer the motor from the VFD to the power line, or from the line to the controller while the motor is at zero speed. Three motor contactors, electrically interlocked, shall be utilized. Motor protection is to be provided in both the "controller" mode and the "bypass" mode by a motor overload relay. The 115 VAC relay control logic, allowing common start-stop commands in the "controller" mode and the "bypass" mode shall also be included within this enclosure. The bypass shall include a door-interlocked, main power input disconnect circuit breaker providing positive shutdown of all input power to both the bypass circuitry and the VFD. The bypass circuit shall include a second door interlocked input disconnect circuit breaker installed in the VFD. This disconnect shall provide the ability to safely troubleshoot and test the controller, both energized, while operating in the "bypass" mode and shall mount within the controller enclosure. K. The VFD manufacturer shall maintain and staff nationwide service centers. Service engineers shall be employed by the manufacturer and provide start up service including physical inspection of drive and connected wiring and final adjustments to meet specified performance requirements. Page 5 of 6

6 PART 3 EXECUTION 3.1 APPLICATION A. Single Phase Motors need not conform to these specifications. B. Motors shall be open drip-proof type, except where specifically noted otherwise. C. Motors shall be energy efficient type. D. Motors located in exterior locations shall be totally enclosed type. E. Adjustable frequency controllers shall be as scheduled on the drawings. F. VFD manufacturer shall provide start-up service for all drives provided. The manufacturer s local representative shall participate in adjusting and balancing operations as stipulated in the specification Division 15, Commissioning of Mechanical Systems. 3.2 PERFORMANCE SCHEDULE: THREE PHASE - Motors shall be tested to IEEE-112, Method B. Minimum efficiencies and power factors are: HP NEMA PERCENT Efficiency Power Factor / / END OF SECTION Page 6 of 6