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    Flywheel UPS

    The CAT Flywheel UPS provides our highest efficiency continuous power solution (>97% efficient). This technology uses a power dense integrated flywheel, which stores sufficient energy to ride through power disturbances such as dips or surges in voltage and/or current. The stored power is immediately available for delivery to a critical load during a power disturbance. This system provides ample ride-through time and allows for an orderly walk-in of the generator set to assume the load for the duration of the disturbance. The integrated flywheel design is modular, supporting easy expansion to meet future power quality/power protection requirements. The CAT Flywheel UPS delivers lower operating costs due to several factors, including lower maintenance and replacement costs, the space savings associated with a reduced footprint (75% smaller than a battery based UPS system) and a yearly energy efficiency improvement of 4%. With the Flywheel UPS, you also benefit from reduced upkeep and maintenance, field-proven mechanical energy storage that is predictable and fail-safe, nearly unlimited life with no fall-off in performance and a broad operating temperature range up to 104° F. Additionally, this technology is environmentally friendly, thereby posing no safety hazards to either your personnel or the environment.

    Working of the CAT FLYWHEEL UPS

    Flywheel Technology

    Flywheel Technology
    4.4” high; 25.5” diameter; 600 lbs
    Each flywheel provides 250kW for ~28 seconds at 50% load


    Flywheel process

    Advantages of CAT Flywheel UPS


    • CAT Flywheel UPS uses an online active filtering design to provide exceptional performance with high efficiency
    • The online active filtering design passes the load current directly through the UPS
    • kVAR and Harmonic current are provided to the load from the Utility Convert
    • A small regulator current is managed between the input and utility convert to provide the active filtering of the input sine wave
    • A small charging current (about 1kW) is drawn from the input to maintain the flywheel charge


    • Single Flywheel
    • 480V @ 60HZ, 750KVA/675KW
    • 400V @ 50/60HZ, 625KVA/625KW
    • Parallel up to 8
    • 3.4m x 1m x 2m
    • 5375 kg


    Maintenance Comparison
    CAT Flywheel UPSDouble Conversion/Battery UPS
    When RequiredMonthly
    – Clean the Flywheel housing– Battery inspection/clean*
    – Clean the oil level site gauge– Torque battery terminals*
    – Check the oil level– Clean internals
    Every 3 MonthsEvery 3 Months
    – Clean/check Air Filter– Clean/check Air Filter
    – Battery Test – Ohmic*
    Every YearEvery Year
    – Change the Vacuum Pump Oil– Battery Test – Resistance*
    Every 3-4 Years
    – Flywheel Bearing Replacement
    Every 5 YearsEvery 5 Years
    – Replace Controller Battery– DC Capacitor Replacement
    – Battery Replacement
    Every 10 YearsEvery 10 Years
    – DC Capacitor Replacement– AC Capacitor Replacement


    Cooling Comparison
    CAT Flywheel UPSDouble Conversion/Battery UPS
    Heat Rejection of 1200kVA UPSHeat Rejection of 1100kVA UPS
    – 83,967 BTU/HR– 250,000 – 339,000 BTU/Hr**
    – 24.6 kW– 74 – 99.35 kW**
    UPS Temp LimitsUPS Temp Limits
    – 0-40°C (32°F – 104°F)– 0-40°C (32°F – 104°F)
    Energy Storage Temp LimitsEnergy Storage Temp Limits
    – 0-40°C (32°F – 104°F)– 25 °C (77 °F)*
    – Life decreases 50% for every 8 °C to 10 °C increase*
    – Batteries have less capacity at colder temperatures*



    • Voltage Range +10% / -15% (programmable)
    • Frequency 60 Hz +/- 10% max (programmable) +/- 3% (default)
    • Power Factor 0.99 at rated load and nominal voltage
    • Harmonic Current Distortion <2% at 100% linear load


    • Steady state Voltage regulation +/-1%
    • Voltage distortion <1% linear loads
    • Frequency 60Hz (mains synchronized)

    – (normal operation +/- 0.2% free running)

    Power Correction

    Voltage is monitored at three locations within the UPS – Input, Bypass and Output

    • Bypass voltage is used to confirm voltage before transfer
    • Input voltage is used to determine disconnect
    • Output voltage is used for correction


    Flywheel UPS Product Line

    Flywheel UPS Product Line

    Flywheel UPS Product Line