1.1 Summary

The following specification is intended for use by consultant engineering firms to provide bidding specifications for products with the quality and performance characteristics required for a three phase hybrid rotary uninterruptible power supply system. The hybrid rotary uninterruptible power supply system, hereafter, will be referred to as the “UPS” or “RUPS”. The RUPS is designed to provide and monitor regulated AC power to critical loads during utility power outages. The system shall include all components required to properly interface with the building’s AC power source, solid-state inverter, rectifier/charger, system bypass, storage battery, and motor generator (M-G) set as described in the following specification.

1.2 Furnished with Equipment

  1. Factory Test Report
  2. Protective Packaging
  3. Installation Drawings
  4. O&M Manual
  5. Warranty Statement

1.3 Documents & Standards

National Electrical Code, NFPA 70-2005.

American National Standards Institute (ANSI); Applicable Standards.


IEEE Standards 45.

Occupational Safety & Health Act (OSHA).

Local Codes & Authorities having jurisdiction for this installation.

1.4 System Description

1.4.1 The basic components of the system shall include a motor generator set, rectifier/charger, static inverter, switchgear, system controls, storage battery, fused battery disconnect, system status, and color touch screen HMI display. The motor generator section must be capable of separation from the electronic portion of the UPS system. This is required to allow outdoor installation of the motor generator section, thereby reducing HVAC requirements for the overall UPS system.

1.4.2 The operation of the UPS shall be based on an online inverter design. The inverter shall remain fully “on” during normal operation and provide 100% of the required load through the rectifier, inverter, and the motor generator (M-G) set.

1.4.3 The system shall be comprised of two major sections that provide true electrical isolation (through mechanical coupling), and battery backup while conditioning raw input power from a utility or engine generator system. The electronics console shall consist of a system rectifier/charger, battery interface filter, and load commutated inverter. The motor generator section shall consist of of a two bearing synchronous motor shaft coupled to a two bearing synchronous generator for complete electromagnetic isolation from input to output.

1.5 System Operation

1.5.1 Normal: The rectifier shall convert the system input AC power to DC power. The DC power will then be applied to the system battery to maintain it in a float charge condition. The rectifier output is also supplied to the naturally commutated inverter. The inverter converts the direct current (DC) to an alternating current (AC) to drive the motor generator, which acts as a rotary filter for the critical downstream load. The motor generator shall store the energy in its rotational mass so as not to require power from the system battery for power outages of 200 msec. of less.

1.5.2 Input AC Power Disturbance/Loss: During an input power failure, the system rectifier will shut down while the inverter draws power from the battery system. No switching of the battery system shall be permitted. The battery must be online at all times. No interruption or transfer of motor generator (M-G) input power will be permitted at this critical time to assure a continuous steady power source for the M-G set. The battery shall be properly sized for full load operation for the specified duration.

1.5.3 Return of AC Input Power: The rectifier/charger shall start to assume the DC load from the storage battery when the normal AC power source returns. The rectifier/charger shall thereafter supply the inverter with full DC power and recharge the storage battery. This shall be an automatic function and shall cause no disturbance to the critical loads.

1.5.4 The transfer to Alternate Source: The if the UPS system senses a fault or out-of-tolerence condition, and an inverter shut down signal shall automatically transfer the crticial loads from the synchronous generator out put to the alternate AC power source without an interruption of power. IF the alternate AC power source is outside normal limits, then the transfer shall be inhibited and the UPS will automatically shutdown.

1.6 Quality Assurance

1.6.1 The manufacturer shall have a Quality Assurance (QA) program in place with an inspection of incoming parts, modular assemblies, and final products. The manufacturer shall have a designated QA manager who is responsible for overseeing the QA, as well as, Quality Control (QC) representatives responsible for actively overseeing the manufacturing process.

1.6.2 A final test procedure for the product shall include a check of all performance specifications and a minimum “burn in” period. An on-site test procedure shall include a check of controls and indicators after installation of the equipment.

1.6.3 Storage, Handing, & Delivery: The equipment shall be shipped on a wooden pallet suitable for forklift handling. The equipment shall be covered with clear plastic sheeting to prevent dust and dirt from entering the unit during shipment. For international shipment, a wooden pallet will need to be constructed of treated wood and shall meet all other specifications and standards required for international freight.

1.7 Submittals

1.7.1 Proposal: Catalog cut sheets and/or data sheets describing the proposed equipment shall be submitted with the proposal. A users listing shall be available upon request giving company name locations and systems installed. All deviations from this specification shall be listed and included with the proposal.

1.7.2 Receipt of Order: A minimum of two sets of installation drawings showing outline dimensions, weights, connections, and a one-line diagram of the UPS shall be sent to the purchaser to be used in planning the installation of the system.

1.7.3: Formal Approval: If a formal submitted approval is required for the project then the following should be requested, submitted, and approved before design/construction of the UPS commences:

  1. Equipment Installation Outline
  2. External Cabling Connection Diagram
  3. Equipment One-Line Power Diagram
  4. Equipment Elevation Drawing
  5. “Other” Site Evaluation Diagrams

1.7.4 Delivery of Equipment: As a minimum, the following shall be provided with the equipment upon its arrival to the final destination:

  1. Operation & Maintenance Manual
  2. System Installation Procedures
  3. System Operation Procedures
  4. System Troubleshooting Instructions
  5. System Maintenance Milestones
  6. Recommended Spare Parts List
  7. Final Test Report Copy

1.8 Warranty

1.8.1  The manufacturer shall state his warranty of the equipment, and in no case shall it be less than 12 months after start-up or 18 months after shipment, whichever occurs fist. A warranty statement will be provided with the equipment and included as part of the overall O&M manual.


2.1 System Size

2.1.1 The RUPS system will be sized to handle anapplication ranging from 400kVA to 5,000kVA.

2.2 RUPS Input:

2.2.1 Input Voltage: 208, 440, 460, 480, or 600 Volts at 60Hz and 208, 380, 400, 415, or 600 Volts at 50Hz. These three phase input voltages are available in 3-wire (DELTA) or 4-wire (WYE) configurations.

2.2.2 Frequency: [50Hz or 60Hz]

2.2.3 Frequency Range: +/- 5% from nominal.

2.2.4 Power Factor: Unity to 0.9 lagging at full load.

2.2.5 Voltage Impulses: To 1500 Volts for not more than 1 millisecond.

2.2.6 Brownout: 15% Continuously low input voltage without use of battery.

2.3 RUPS Output: 

2.3.1 Output Voltage: 208, 440, 460, 480, 600 Volts at 60Hz and 208, 380, 400, 415, or 600 Volts at 50Hz. For 400Hz requirements 200/115 and 208/120 Volts is available.These three phase input voltages are available in 3-wire (DELTA) or 4-wire (WYE) configurations.

2.3.2 Frequency: [50Hz, 60Hz, or 400Hz].

2.3.3 Frequency Regulation: +/- 0.5Hz from nominal.

2.3.4 Voltage Regulation: +/- 0.5% (Steady State).

2.3.5 Drift: Less than +/- 1%.

2.3.6 Transient Regulation: 50% Load step. +8%, -10% for 30 cycles maximum.

2.3.7 Loss/Return of AC Input: +/- 0.5% for zero cycles maximum.

2.3.8 Phase Displacement: 120° +/- 1° (Balanced Load), 120° +/- 3° (25% Imbalance).

2.3.9 Overload Capability: 110% (2 Hours), 125% (10 Minutes), 150% (2 Minutes).

2.3.10 Inrush Current: The system shall be capable of withstanding the inrush current of any motor whose peak inrush does not exceed 50% of the full load current rating of the generator.

2.4 Environmental

2.4.1 The RUPS shall be suitable for installation indoors (Altitude o to 12,000 meters or 0 to 4,000 feet) with ambient temperatures from 0° to +40°C (32° to 104°F) with 1% de-rating for each 1°C above 40°C up to 50°C, and relative from 0% to 95% non-condensing.

2.4.2 Site Conditions:

  1. Ambient: 0° to 40°C (32° to 104°F). 50°C and 55°C (Optional).
  2. Humidity: 0% to 95% Non-condensing.
  3. Audible Noise: 90 dB (NEMA 1). Lower noise levels (Optional).
  4. Construction: Suitable for indoor applications. Outdoor enclosures (Optional).
  5. Bearings: Grease lubricated, anti-friction type.
  6. Service Factor: Continuous duty, 24-hour service.

2.5 Physical Characteristics 

2.5.1 Motor Generator (M-G) Construction: The motor generator set shall consist of brushless, two bearing synchronous motor with brushless exciter. Allowable temperature rise shall be 105°C. The system will be started via a reduced current motor start, pony motor type. The RUPS shall be built with electrically operated utility input circuit breaker and an inverter bypass circuit breaker. The generator shall be brushless, two bearing synchronous generator with voltage regulator and paralleling capability. Allowable temperature rise shall be 105°C. The motor generator will be connected via a flexible gear type coupling between the motor and generator, adjustable to match the input and output phase angle. Besides motor and generator controls, the brushless directed connected AC exciter shall be built with rotating filters. The whole motor generator (M-G)  set shall be built on separate mounting steel base with spring type vibration isolators.

2.5.2 Rectifier/Charger: The rectifier/charger section shall consist of a utility fed electrically operated input circuit breakers and a voltage regulated, current limited, three phase SCR bridge rectifier. The rectifier/charger shall provide power to the DC link and maintain the battery in a float condition. It shall be regulated to avoid overcharging. The rectifier/charger shall have sufficient capacity to provide full load power to the inverter, with a reserve capacity of 25% for simultaneous battery recharging. This will allow recharge of a completely discharged battery system in 10 times the discharge period.

The rectifier/charger shall be designed for use with a [140, 240, 260] cell nominal battery system. The rectifier/charger shall limit currents from 1.1 to 1.25 times nominal full load (Adjustable). The battery voltage shall regulated to provide a float voltage of 2.25 volts per cell (VPC). The float voltage can be console. Separate battery charges shall not be permitted. The rectifier/charger shall have an IEEE 5.19.1992 compliant input filter.

2.5.4 Inverter: The inverter section of the system shall be all solid state, capable of accepting the DC output of the battery, and delivering AC power within specified limits to the motor generator set. The inverter shall have necessary logic and controls to automatically start-up and accept the M-G set load. It shall be rated for 100% continuous duty. The inverter shall contain an internal oscillator capable of maintaining output frequency of the protected motor generator within specified limits (+/- 0.5Hz).

The inverter shall be load commutated and shall not require commutation SCRs or circuits. The inverter semiconductors shall be protected by fast acting current limiting fuses. The inverter shall be capable of full load operation from any storage battery system with a float voltage of 540 Volts DC or a low voltage limit of 396 Volts DC. The inverter output voltage and frequency characteristics of the system shall maintain the protected motor generator set’s output within the manufacturer’s specification during operation on battery for an output voltage (+/- 0.5) and an output frequency (+/- 0.5Hz).

2.5.4 Automatic Bypass Switch: The RUPS system shall contain two electromechanical switching devices to automatically transfer the critical load fro normal operation to bypass in the event of a component failure. The bypass operation must have no effect on the critical load. Use of a solid state static switch is not acceptable.

  1. Inverter Bypass: The inverter bypass switch shall automatically transfer the motor generator set from inverter to utility power under the following two conditions. First, inverter output fails for any reason. Second, manual command – critical load continues to be powered by the motor generator. The motor generator shall provide total electrical isolation, voltage and frequency regulation as long as the input voltage source is within +/- 20% steady state and during momentary sags of -40%.
  2. System Bypass: The system bypass switch shall automatically transfer the critical load from motor generator power to utility power under the following conditions. First, M-G set over voltage and under voltage. Second, winding over temperature. Third, motor or generator over temperature.

2.6 Storage Battery

2.6.1 Voltage: 567 Volts DC, 252 Cells.

2.6.2 Final Discharge: 1.70 volts per cell; equalize of 106% of float.

2.6.3 Protection Time: [5, 10, 15, 20, 30, 60] Minutes as required.

2.6.4 Enclosure: NEMA 1 (Outdoor Enclosures – Optional).

2.6.5 The storage battery shall have sufficient capacity to maintain the UPS output at full rated load for the time specified herein. The battery shall be designed for use with UPS systems and shall be equipped with safety vents on the containers. The battery shall be lead-calcium type.

2.6.6 The storage battery shall be furnished with cabinets and connecting hardware. The battery shall be delivered charged and ready for operation.

2.6.7 Battery Disconnect Switch: A safety switch rated for the proper DC voltage and final discharge ampacity shall be furnished with the RUPS. This switch shall be placed at the output of the storage battery. Battery disconnect switch shall be safety interlocked by UPS logic to prevent close to the UPS bus when the RUPS does not have utility power applied.

2.7 System Status & Controls

2.7.1 Instruments: Digital 1% for the following:

  1. AC Input & Output Volts
  2. AC Input & Output Frequency
  3. AC Input & Output Current
  4. Motor Voltage
  5. DC Link Voltage
  6. Rectifier Output Current
  7. Battery Charge/Discharge Current
  8. Input kW
  9. Output kW
  10. Percentage Capacity

2.7.2 Color Touch Screen Mimic Display:

  1. Primary Source – (On/Off)
  2. Auxiliary Source – (On/Off)
  3. Input Breaker – (Open/Closed)
  4. Rectifier/Charger – (On/Off)
  5. Inverter Bypass – (Open/Closed)
  6. Inverter – (On/Off)
  7. Motor Generator Set – (Run/Off)
  8. System Bypass – (Open/Closed)
  9. Generator Breaker – (Open/Closed)

2.7.3 Status & Fault Indicators:

  1. Input Over Voltage
  2. Input Under Voltage
  3. Battery Circuit Breaker (Open/Closed)
  4. High Battery (Volts)
  5. Low  Battery (Volts)
  6. System on Battery
  7. Fuse (Open)
  8. Battery Choke Over Temperature
  9. Bearing Over Temperature
  10. Winding Over Temperature
  11. Motor Overload
  12. Inverter Over Temperature
  13. Generator Over Voltage
  14. Generator Under Voltage
  15. Output Under Frequency
  16. System Not In-Phase
  17. Input Circuit Breaker (Open/Closed)
  18. Generator Circuit Breaker (Open/Closed)
  19. System Bypass Circuit Breaker (Open/Closed)
  20. Inverter Bypass Circuit Breaker (Open/Closed)
  21. UPS Mode
  22. Inverter Bypass Mode

2.7.4 Indicators & Controls:

  1. Alarm (Audible Alarm)
  2. Alarm Silence/Lamp Test
  3. Saves Counter
  4. Fault Reset
  5. System Reset
  6. Emergency Stop (E-Stop)

2.8 Optional Features

2.8.1 Remote Monitoring System: There are many methods that can be utilized to allow the user to interface with the UPS system giving them a wide range of monitoring and control options. Options include:

  1. Modbus: Modbus over serial line with RTU protocol. A Modbus serial port is provided to remotely access the RUPS Modbus registers and status bits. All the RUPS analg metering information, operational status information, and messaging will be provided via Modbus protocol. Modbus over TCP is also available. A Ethernet is provided to remotely access the modbus registers and status bits the same as RTS but with a TCP interface that runs on Ethernet. Please contact factory for additional information.
  2. Web Based: The web based remote monitoring/control feature puts the user at the control screen of the RUPS, anywhere in the world, via the World Wide Web (www). The web interface can be programmed to give limited access based on responsibility or full access of the whole user interface. Please contact factory for additional information.
  3. Remote Color Touch Scree Panel: All RUPS analog metering and operational status are displayed on a remote screen that can be installed in secure or remote locations. All real-time data is displayed with a dedicated communications ink. Link via Profibus DP or Profinet Industrial Ethernet. Please contact the factory for additional information.

2.8.2 Sound Attenuated Enclosure: The RUPS will be built in a sound attenuation enclosure to reduce the noise emission to less than 75dB when measured at industry standards. The attenuated enclosure will enclosure the RUPS, and shall be equipped with noise absorbing material, which won’t restrict the system’s overall air flow. It also allows an extra level of protection against dust and other particulates.

2.8.3 Outdoor Rated Enclosure: The RUPS will be built to endure the harshest outdoor environments – sand, snow, rain, salt, etc. The enclosures will be built to NEMA 3, 3R, 4, 4X, 12…standards. For large systems (400kVA+) or “turn-key” applications the RUPS can be built into an ISO container allowing for easy transportation, installation, and maintenance.


3.1 Manufacturing

3.1.1 The manufacturer shall design, build, and fully test the RUPS system. If requested by the customer, the manufacturer shall arrange shipment of the RUPS the the customer’s requested destination.

3.1.2 The manufacturer shall prepare and deliver the required drawings and manuals with the RUPS.

3.2 Site Preparation

3.2.1 The owner shall prepare their site for installation of the RUPS.

3.2.2 The owner shall arrange for local electricians to install the RUPS.

3.2.3 The RUPS shall be installed in accordance with local codes and the OEM’s recommendations.

3.3 Field Service Start-up & Installation

3.3.1 The RUPS is to be checked and inspected by the field service representative from the OEM to confirm proper installation.

3.3.2 The RUPS is to be started-up by the field service representative from the OEM to confirm proper operation. The OEM representative should provide commissioning, training, etc. if requested by the customer.