Power Density

The most power dense UPS
in its kVA range


Reduces failure rates by 80%

Total Cost of Ownership

Up to 30% annual OPEX savings


Flywheel 101

The key to CleanSource 625HD’s unmatched value is Active Power's patented integrated flywheel UPS technology.

Flywheel systems store kinetic energy - energy produced by motion - by constantly spinning a compact rotor in a low-friction environment. When short-term backup power is required because utility power is lost, the inertia allows the rotor to continue spinning and the kinetic energy is converted to electricity. CleanSource 625HD provides up to a minute of UPS runtime, depending on the load and level of UPS redundancy, providing more than enough time for backup diesel generators to start and support the load.

• 12.5" high; 25.5" in diameter; 1700 lbs
• Constantly spins at ~ 7,700 rpm
• Rough vacuum to reduce losses
• Stores 10.5 MJ of energy
• 20 year life


Parallel Online Architecture

CleanSource 625HD uses a flywheel-based power module as its basic building block . Each module is rated at 625 kVA / 625 kW. The flywheel machine is integrated into Active Power’s Parallel Online Architecture to provide an energy efficient, reliable, and high performing UPS system.

CleanSource 625HD systems can be paralleled for redundancy or capacity, supporting up to 3 MW of backup power in a single paralleled system.

Power Quality

CleanSource 625HD provides clean, reliable power to your mission critical operations, protecting loads against all nine IEEE power disturbances. CleanSource 625HD senses input power deviation from nominal, eliminates transients and corrects the output to the prevailing nominal. Upon a complete loss of input power or a major deviation in input voltage or frequency, the UPS will disconnect from the utility source and the flywheel's stored energy will be used to support the load until the backup diesel generator comes online. Further, CleanSource 625HD provides fully online power protection that combines high efficiency without sacrificing performance.

Innovative Design

CleanSource 625HD was designed from the start to be the most innovative, efficient, and compact UPS in its class. CleanSource 625HD supports 625 kW of backup power in just two cabinets consuming 35 square feet of floor space – less than half its leading competitors.

The primary source of the compact design is the flywheel energy storage system. It packs 10.5 MJ of energy into a 3’ x 3’ x 3’ package rather than four or more bulky and expensive battery cabinets.

CleanSource 625HD has also been designed with ease of installation, operation, and service in mind.

Display and Monitoring

The CleanSource 625HD system features a state-of-the-art operator interface to provide users with maximum visibility to system status, performance, events, and maintenance requirements. The brilliant 10" LCD display and intuitive touch-screen control make it easy to view any level of detail in one of 10 languages.

In addition, Active Power's CleanSource View monitoring and control software enables real-time system visibility from virtually anywhere. By using common data and connectivity with CSView and data integration options to your Building Management System (BMS), CleanSource 625HD provides you the degree of system visibility and service that you need to manage your critical power infrastructure.

Inside CleanSource 625HD


Power Density

CleanSource 625HD supports nearly 20 kW per square foot compared to a legacy bettery based UPS at under 9kW per square foot, more than double the power density of traditional solutions. All told CleanSource 625HD consumes just 35 square feet of floor space – less than half its leading competitors.

The primary source of the space savings is the absence of expensive and bulky battery cabinets that can double the amount of space your UPS system takes up. Further, CleanSource 625HD’s environmental tolerance is tremendously robust compared to batteries, tolerating ambient temperatures up to 40C and reducing the cooling requirements of your electrical system.


The integrated flywheel energy storage at the core of CleanSource 625HD makes it inherently reliable, delivering predictable, consistent backup power. The normal state of CleanSource 625HD is with the flywheel spinning constantly, storing kinetic energy. When called upon during a utility outage, the flywheel is ready to assume the load. By contrast, battery failures are the leading cause of UPS load loss and system downtime. A study by Mtechnology, Inc. shows that CleanSource 625HD will reduce the risk of electrical system failure by 80% compared to traditional UPS with batteries. View our White Paper for more information.

The Extended Runtime option further increases the reliability and availability of your UPS. By adding a second energy storage source, Extended Runtime makes CleanSource 625HD the most reliable UPS system available.

Total Cost of Ownership

CleanSource 625HD combines a competitive first cost with lower ongoing operating expenses – up to 30% lower than legacy UPS over five years. The result is a dramatic TCO benefit for your data center, with net savings to you on day one of operation.

Superior energy efficiency – over 96% efficient at 40% load

Reduced cooling needs – no need for dedicated cooling for batteries

Lower maintenance requirements – routine annual check-up and bearing change every third year

No battery changes – integrated flywheel with 20 year life


Extended Runtime

For applications requiring additional UPS autonomy, CleanSource 625HD supports an Extended Runtime option. Standard valve-regulated lead acid (VRLA) batteries supporting up to 30 minutes of additional energy storage supplement the flywheel to provide additional flexibility and reliability to your design.

If a power disturbance occurs with Extended Runtime in place, CleanSource 625HD first draws on flywheel energy to support the load and switches to battery power for longer outages. Extended Runtime provides additional runtime in the event of a complete utility failure and enhances overall battery reliability by eliminating short duration battery discharges, a primary factor in battery degradation. Further, the flywheel and batteries are independent energy storage systems with either system being capable of supporting the load in case of a disturbance. This dual energy storage approach creates the most reliable UPS system available.

Key Benefits

Adding a battery cabinet to a CleanSource 625HD unit, by choosing the Extended Runtime option, provides a fully integrated UPS that increases overall system reliability, eliminates severe step-load on the battery, and mitigates coup de fouet effects on the battery. Key Benefits of this solution include:

• Additional UPS runtime
• Two independent energy storage sources, improving system reliability
• Longer battery life
• Better battery performance
• Up to 40% lower Total Cost of Ownership than battery-only UPS systems

Unmatched Energy Storage: CleanSource 625HD with ExRC


Maintenance Services

Regular maintenance and service prevents potential small problems from becoming issues that could cause costly downtime. Active Power has designed the CleanSource 625HD with ease of maintenance in mind to ensure your critical power infrastructure operates with the utmost reliability. Unlike legacy systems, which require monthly or quarterly inspections to ensure reliability, CleanSource 625HD requires simple, non-invasive annual maintenance and a routine bearing change every third year. This streamlined maintenance schedule both restores your UPS to factory-like condition and reduces downtime during its operating life, improving the availability of your mission critical operations.

Warranty and Service Plans

Active Power’s limited warranty guarantees no-cost repair labor and parts for 12 months after system installation. Additional extended warranty options are available.

Active Power offers flexible service plans designed to meet individual customer needs over the life of the system. Select the plan tailored to best meet your needs and be assured that everything will be taken care of by a qualified, certified Active Power technical support engineer. In addition, PowerService plans provide a number of benefits beyond quality technical support, including:

• Lower, predictable costs
• Flexible payment options
• Priority scheduling and response

Professional Services

Rely on our trained professionals for expert assessment, implementation, maintenance, and support during every phase of your critical infrastructure system deployment and operation. Whether you are looking at a standalone UPS system or a complete turnkey infrastructure solution, we can assist from start to finish.

CleanSource HD UPS
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The Active Power CleanSource 625HD UPS system provides 625 kVA of always-on power protection in the most compact footprint in its kVA class. Competitively priced out-of-the-box, the new CleanSource 625HD UPS operates at up to 97% efficiency and delivers 30% annual OPEX savings. For access to full guide specifications and product manuals, please contact us.
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