4th Generation Modular
Uninterruptible Power Supplies
10kW – 3.6MW

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CumulusPower is the latest generation of true modular UPS technology, offering the highest levels of availability and the lowest total cost of ownership (TCO). CumulusPower is designed with flexibility for future growth in mind. Its extensive portfolio of frame sizes range from

20 to 600kW and comprise of UPS modules with power of 10, 20, 25, 50 and 60 kW. Systems are parallelable up to 3.6MW.  CumulusPower is ideally suited to protect critical loads within the data centre, finance and banking, and medical sectors.

High availability

Full redundancy

Industry leading VFI 97% efficiency

Bypass redundancy

Distributed architecture

No single point of failure

Small footprint

+0.51 MW/m²

Outstanding overload capability

124% continuous operation in overload

Minimized total cost of ownership

Ultra-safe Eco mode

99.4% efficiency in Eco mode operation

Swiss quality


Thanks to our extensive failure analysis research and insights gathered from 25 years of field experience working with a large number of data centres and other critical environments, our power protection solutions have reached the highest levels of availability to reduce downtime risk, avoid costly errors, and increase energy efficiency. To respond to the highest availability requirements i.e. to eliminate risks that may cause downtime of business-critical applications, CENTIEL has 

developed a new series of fault-tolerant, Three-phase, true modular UPS-systems called CumulusPower™. Unlike traditional centralised parallel multi-module systems, the advanced CumulusPower™ technology combines a unique Intelligent Module Technology (IMT), with a fault-tolerant parallel architecture, called Distributed Active-Redundant Architecture (DARA), thereby fulfilling the highest availability and reliability requirements.

Distributed Active-Redundant Architecture (DARA)

The Distributed Active-Redundant Architecture of the CumulusPower™ product line is designed to respond to the highest availability requirements, through the implementation of the “democratic” majority load transfer decision-making in the event of a critical failure, and correct management of the load sharing to avoid crosscurrents between modules. The communication between the logic circuits of the modules is accomplished by means of a fault-tolerant dual communication BUS. In the event of a critical failure, every module will decide, by means of its

logic circuit, whether the load should remain on the inverter or be transferred to the bypass. The load transfer will be conducted depending on the decision made by the majority of the modules. In order to avoid crosscurrents between the modules, a master-slave load sharing technique is adopted. The first module becomes the master which provides the load value to be shared by the rest of the modules (slaves). If the master fails, the next module will automatically become the leading master.

DARA Modular Architecture

Mains Bypass Line
Mains Rectifier Line
Data communications
DC Batteries
AC Output Line

Intelligent Module Technology (IMT)

The CumulusPower™ modules are equipped with all hardware (power circuits) and all software (intelligence and monitoring) functions, making them fully independent and capable of safely isolating from the multi-module system whenever an internal fault occurs. If that should happen, the remaining modules will continue to provide protected power to the critical load without interruption.

 The integration of hardware and software in each module enables the elimination of all single points of failure which could compromise the power of the critical application. The core technology of the CumulusPower™ product family is based in 3 Intelligent Modules sizes that can be combined to create systems from 10kVA/kW to 3MW


Protect your critical application, minimise human error.

Availability to the next level 99.9999999% (9 nines)

The higher the Availability, the lower the downtime. By eliminating any single point of failure, adding active-redundant technology, preventing human error and reducing the time to maintain and repair, CumulusPower™ delivers an industry-leading Availability of 9 nines to fulfil the needs of the most critical power applications. CumulusPower™, true modular UPS, takes downtime from seconds to the milliseconds level. Availability is formally defined as


CumulusPower™ maximizes the Mean Time Between Failure (MTBF) while minimizes the Mean Time To Repair with a series of future.

Minimised MTTR

Parallel system availability increases with the reduction of the Mean Time To Repair (MTTR). In-frame per-module bypass fuses minimise the time it takes to re-establish a system in an event fault.

Triple-mode parallel bus

Multi-frame connection is one of the advantages of horizontal scalability. Communication between frames and modules is critical, nevertheless, for some architectures, it is still a single point of failure. CumulusPower™ parallel communication is provided with a unique triple-mode parallel bus, that consists of three independent communication lines and three independent electronic circuits. With triple redundancy in the communication lines and electronic circuits the risk of disconnection or short-circuit on any of the communication lines is mitigated eliminating the single point of failure.

Full Bypass redundancy

Some UPS architectures still use centralised critical components like a Single Bypass Architecture (SBA). Centralised components in a parallel system represent single points of failure. Unlike the centralised architectures, Centiel’s modular UPS, CumulusPower™, is equipped with a Distributed Bypass Architecture (DBA), that brings full redundancy even in the bypass line, avoiding any system’ single point of failure.

Safe Smart Battery test

CumulusPower™ battery tests are programmable and safe. Smart Battery Booster architecture allows the UPS to perform battery monitoring, tests and health status diagnosis without the need for mains disconnection.

Hot-Swappable with minimised human error

CumulusPower™ modules can be swapped without the need to switch over the load to bypass. Individual module parallel isolators disconnect from the system, minimising human error and increasing Availability.

System costs

Flexibility: Same core technology different solutions

CumulusPower™ fits in a 19” (IM10/20) to provide the maximum flexibility to the final application. Centiel’s flexible solution approach can customize a frame solution to satisfy specific needs.”

1. Reduced up-front investment

Compared to a standalone UPS solutions or centralised bypass architectures, Centiel’s scalable modular UPS have a lower total up-front investment cost, allowing you to grow your power protection capacity as your demand increases.

2. Avoid oversized diesel generators

In the event of a mains failure our Unity Power Factor and Smart-Battery-Booster ensure that every switch over happens smoothly, minimising in-rush current, avoiding generator destabilisation and eliminating the need for generator oversizing.

3. Eliminate ad-on external components

Back-feed protection in every module and maintenance bypass, bypass fuses and battery DC breakers within the UPS frame eliminate the need for external components connections, reducing Total Cost of Ownership.

4. Save on batteries

Batteries represent a substantial part of a project cost structure. With CumulusPower™ you have the flexibility to select the number and type of battery blocks that best suit your application. Letting you decide on a case by case basis the best way to optimise total system cost.

5. High efficiency means less heat

CumulusPower™ industry-leading VFI 97% efficiency and its flat efficiency curve, contribute to low energy losses and heat dissipation, reducing the size and cost of cooling systems.

6. High battery charging current capability

The innovative modular design of CumulusPower allows a higher charge current capability whilst protecting the batteries at all times. This allows for faster, safer charging.

Total cost of ownership

Load Demand  Module status: On  Module state: Active sleep

Modules On


Maximum Efficiency Management (MEM)

Use energy only when it is needed. Cumuluspower™ incorporates a user enabled intelligent MEM that only uses as many modules as necessary to match the load demand. MEM constantly looks for the optimal energy efficiency point. If the load demand decreases, MEM calculates that a reduced number of modules could support the load whilst still maintaining redundancy. The surplus modules enter an “active-sleep” mode to optimise the overall energy consumption. If the load increases, and additional modules are required to support the higher load, “active-sleep” modules are instantaneously reactivated to support the load.

Optimise valuable space (Minimized Footprint)

With only 0.29m² for 10/20 kW and 0.44m² for 30/40/60 kW, the PremiumTower ™ optimises valuable floor space, eliminates the cost of an additional battery cabinet, and simplifies the installation.

Provide industry-leading availability

The higher the Availability, the shorter the downtime. Eliminating single points of failure, adding active-redundant technology, helping to prevent human error and reducing the time to maintain and repair allows Cumuluspower™ to deliver an industry leading Availability of 9 nines to fulfill the needs of the most critical power applications. Cumuluspower™ reduces downtime from seconds to the milliseconds.

Availability is formally defined as

The advanced Cumuluspower™ design maximises the Mean Time Between Failure (MTBF) whilst minimising the Mean Time To Repair.

Minimised life-time maintenance cost

Preventative maintenance is important to maximize availability. Centiel develop products to reduce the time and costs associated with preventative maintenance and minimise the number of components that require routine replacement. The innovative design of CumulusPower also simplifies these replacements, reducing the time and cost involved.

Provide outstanding overload capability (Outstanding Overload Capability)

With continuous operation at 124% overload, mission critical applications will be safe in the event of unexpected load demands.

Reduce your energy bill

High efficiency means less heat dissipation, and therefore less energy wasted. Cumuluspower™ reduces the energy consumption of the power protection equipment and the associated cooling systems.

Use energy only when
it is needed with CumulusPower™
active-sleep mode.

Other UPSs

CumulusPower ™ Savings


Keeping a healthy UPS should be safe and easy: Serviceability

State of the art service tools

CumulusPower™ service tools allow technicians, to connect, download events, verify configuration and change parameters of the UPS with a simple tap of the screen. The mobile and tablet app provides a full toolbox to read and interpret the health of the system.

Safe power-upgrades: Reduce human error

Power capacity upgrades and module substitution are two critical operations where human error can compromise the system load. To eliminate this risk every module in a CumulusPower™ frame can be fully isolated from the parallel system, thanks to the parallel isolator. This isolator allows technicians to perform a full module test and parameters configuration in a running system without the need for load disconnection or for your system to switch to bypass. This feature eliminates the possibility of connecting a faulty module to the parallel system which could compromise the connected load.

Icon 3
Back-feed protection: Increased safety and reduced system cost

Embedded into the module as standard is back-feed protection which increases service personnel safety, reduces total system cost and avoids external components.

Per-module 3” graphical user interface

With CumulusPower™ graphical user interface it is easy to read measurements, parameters, messages, alarm and any parameter of the UPS.

Advanced Performance

Unity Power Factor (kVA = kW)

CumulusPower™ provides unity power factor output which avoids the need for system oversizing.

High Efficiency 97% (VFI)

With a best in class efficiency of 97% in double conversion mode (VFI), CumulusPower™ provides the lowest Total Cost of Ownership.

Outstanding overload capability

With a 124% continuous operation in overload condition, mission critical applications will be safe in the event of unexpected load demands.

Exceptional short circuit capability

With a Short Circuit Capability of 3 times nominal current (3 x In), CumulusPower™ is able to clear output circuit protection in milliseconds.

CumulusPower™ fault
tolerant three-phase UPS

From the designers of the 1st three-phase
transformerless UPS and the 1st, 2nd
and 3rd generation modular UPS,
comes the 4th generation.

Product Line

Intelligent Modules

10 kVA/kW20 kVA/kW25 kVA/kW
50 kVA/kW60 kVA/kW

Technical Data Sheet

Bespoke application?

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