Liebert® NXL™ UPS
Single-Module Uninterruptible Power System Rated
These specifications describe requirements for an Uninterruptible Power System (UPS). The UPS shall automatically maintain AC power within specified tolerances to the critical load, without interruption, during failure or deterioration of the normal power source.
The manufacturer shall design and furnish all materials and equipment to be fully compatible with electrical, environmental and space conditions at the site. The UPS shall include all equipment to properly interface the AC power source to the intended load and be designed for unattended operation.
The UPS and all associated equipment and components shall be manufactured in accordance with the following applicable standards:
The UPS shall be UL listed per UL Standard 1778, latest edition, Uninterruptible Power Supplies, and shall be CSA certified.
The UPS shall be provided with a withstand label denoting the maximum source fault short circuit current that is applicable to the unit. The withstand rating shall be independently verified by a nationally recognized third-party lab.
The UPS shall withstand input surges to both the rectifier and bypass when configured as a dual-input unit without damage per the criteria listed in ANSI C62.41, category B3 (6kV). The manufacturer shall provide evidence of compliance upon request.
The UPS shall comply with FCC Rules and Regulations, Part 15, Subclass B, Class A. This compliance is legally required to prevent interference with adjacent equipment. The manufacturer shall provide evidence of compliance upon request.
The UPS shall be compatible with the wiring practices, materials and coding in accordance with the requirements of the National Electrical Code, OSHA, and applicable local codes and standards. Provisions shall be made in the cabinets to permit installation of input, output and external control cabling, using raceway or conduit for top and bottom access to input, output, bypass and DC connections. Connection cabinets shall provide for wiring gutter and wire bend radius as defined by the NEC and UL.
The UPS shall be sized to provide a minimum of ____ kW and a minimum of ____ kVA output.
The UPS shall be able to power at full rated output kW loads with power factor between 0.9 lagging and 0.95 leading.
Load voltage and bypass line voltage shall be ____VAC, three-phase, three-wire in and out or four-wire in and out. When the bypass is three-wire, the UPS shall be supplied with a main bonding jumper to configure the UPS source as separately derived.
Input voltage shall be ____VAC, three-phase, three-wire.
The battery shall support the UPS at 100% rated kW load for at least _____ minutes at 77°F (25°C) at startup.
The UPS shall have a 12-pulse solid-state rectifier with input filter, with automatic disconnect for input power factor control. The disconnecting level shall be adjustable to allow operation with generators that are sensitive to leading power factor loads.
The UPS shall be equipped with an input isolation transformer to provide isolation for DC ground faults and an output isolation transformer to allow connection as a separately derived source when a main bonding jumper is installed.
Modes of Operation
The UPS shall operate as an on-line reverse transfer system in the following modes:
Normal: The critical AC load is continuously powered by the UPS inverter. The rectifier/charger derives power from the utility AC source and supplies DC power to the inverter while simultaneously float charging the battery.
Economy: The critical load is continuously powered by a method that provides higher efficiency than that provided with normal operation.
Emergency: Upon failure of utility AC power, the critical AC load is powered by the inverter which, without any switching, obtains its power from the battery plant. There shall be no interruption in power to the critical load upon failure or restoration of the utility AC source.
Battery Ground Fault: Upon occurrence of a battery ground fault the AC load shall be maintained by the inverter, and a battery ground fault alarm shall be signaled.
Recharge: Upon restoration of the utility AC source, the rectifier/charger powers the inverter and simultaneously recharges the battery. This shall be an automatic function and shall cause no interruption to the critical AC load.
Bypass: If the UPS must be taken out of service for maintenance or repair, the static transfer switch shall transfer the load to the bypass source. The transfer process shall cause no interruption in power to the critical AC load.
Off-Battery: If the battery is taken out of service for maintenance, it shall be disconnected from the rectifier/charger and inverter by means of an external circuit breaker. The UPS shall continue to function and meet all of the specified steady-state performance criteria except for the power outage backup time capability.
Self-Load Test: During system commissioning, the charger, battery, inverter and bypass of the UPS module shall be tested at full load without the need for an external load bank. Testing mode shall use the bypass source as the load.
The UPS shall be able to support 100% critical load and maintain full battery charging with the following conditions occurring simultaneously:
Any altitude, within the specified operating range up to 5,000 ft. (1,500m) elevation
Any ambient temperature, within the specified operating range of 32°F to 104°F (0°C to 40°C)
Any one failed fan
Any input voltage within the specified range, +10% to -15% of nominal
Air filters 50% blocked
The following performance is required for normal and emergency operations.
Rectifier Voltage Range: +10%, -30% of nominal (no battery charging below -15%)
Rectifier Frequency Range: ±5Hz
Rectifier Walk-In: 0% to 100% of full rated load over 1-30 seconds (adjustable)
Rectifier Sub-Cycle Magnetizing Inrush: Not to exceed eight times normal full load input current
Rectifier Power Factor: Minimum 0.89 lagging at full load with nominal input voltage
Two-Step Rectifier Input Current Limit:
Step 1 - Independently adjustable 25-125% of normal full load input current
Step 2 - Independently adjustable 25-125% for on-generator operation
Two-Step Battery Charge Current Limit:
Step 1 - Independently adjustable 0-20% of maximum battery discharge current
Step 2 - Independently adjustable 0-20% of maximum battery discharge current
Rectifier Current Distortion: Less than 4% THD at full load input current
Bypass Voltage Range: +15%, -20%
Bypass Frequency Range: ±5Hz
Rectifier and Bypass Surge Protection: Sustains input surges without damage per criteria listed in ANSI C62.41, category B3 (6kV)
Withstand Rating: 480V units shall carry a 65kA standard withstand rating; 100kA rating shall be available (optional). 575V and 600V units shall carry a 35kA standard withstand rating, and 65kA rating shall be available (optional). All withstand ratings shall be UL-tested and certified.
Load Rating: 104% continuous load rating at 104°F (40°C) for any combination of linear and non-linear loads
Voltage Regulation: ±1% for balanced load, ±2% for 50% unbalanced load for both line-to-line and line-to-neutral unbalances
Voltage Adjustment Range: ±5% manually
Line Drop Compensation: Adjustable 0 to +5% of nominal voltage
Frequency Regulation: 0.1%
Efficiency: Defined as output kW/input kW at rated lagging load power factor. Not less than 92% at 50% load and not less than 91.3% at 100% load.
Balanced loads 120° ±0.5°
Unbalanced loads 120° ±1°
Voltage Transients (Average of All Three Phases):
100% load step ±5%
Loss of/return to AC input power ±1%
Output Voltage Transients
Voltage transients shall be limited to a maximum deviation from nominal system output volts of plus or minus 5%, with recovery to within 1% of the nominal output voltage within one electrical cycle (16 milliseconds) for each of the following conditions. Limits shall apply to any UPS load within the UPS rating, and frequency shall be maintained at 60 Hz ±0.1 Hz. The system shall not transfer to bypass under these conditions (except item 3).
100% load step
Loss or return of AC input power, or momentary sags, surges or spikes on the input to the UPS (all three phases or single phase)
Uninterrupted transfer of the critical load to and from the UPS output and bypass power line (manually initiated or automatic)
Voltage Harmonic Distortion:
Maximum 2% RMS total (linear load)
Maximum 2.5% RMS total for up to 100% non-linear load, per IEC 62040-3
Overload at Full Output Voltage with ±1% Voltage Regulation:
The overload rating of the UPS shall be the rating that can be demonstrated after operating at full load continuously at maximum operating temperature with a fan failed.
110% of full load for 60 minutes
125% of full load for 10 minutes
150% of full load for a minimum of 60 seconds
Current Limit: Up to 200% of full load current
Inverter Only: 200% of normal full load current for 200 milliseconds, or 155% of normal full load current for 5 seconds (when bypass is not available).
Bypass Available: 1,000% for 200 milliseconds in inverter pulse-parallel operation when bypass is available.
The AC output neutral shall be electrically isolated from the UPS chassis. The UPS chassis shall have an equipment ground terminal. A terminal for bonding the system neutral to the facility service entrance ground (customer-supplied cable) shall be provided.