The Riello Multi Sentry 20kVA/18kW uninterruptible power supply from Critical Power Supplies is an on-line double-conversion UPS with a built-in battery pack designed to give 5 minutes runtime at full load. The standard runtime can be extended using additional battery extension packs. The UPS has a single phase output and can be configured to run from a three or single phase input supply. Typical applications: Blade servers, comms rooms, server rooms and datacentres.

Multi Sentry has a very high operating efficiency (94%), high input power factor, advanced battery management and can work in one of several operating modes: On-line, Economy, Smart Active and Standby/Off, as well as operating as a frequency

Features and Benefits.

Multi Sentry UPS have been designed for an easy install, especially on sites with limited power capacity available, a generator and harmonic compatibility problems. Typical features include:

- low input current distortion – less than 3%
- high input power factor 0.99
- power walk-in function to achieve progressive rectifier start-up
- delayed start-up on mains power supply return

The UPS also acts as a high performance filter to protect its supplies from load induced harmonics and reactive power.

Multi Sentry has a unique battery care system to optimise battery performance, extend working life and guarantee the UPS is fit to deliver its full-rated runtime when called upon to do so – in the event of a complete mains power failure. The UPS is designed to operate with a range of battery types: VRLA AGM and GEL lead-acid batteries including open-vented types, in addition to Ni-Cads.

Specific Battery Care features include:

- One-level recharge to meet the requirements of the most common VRLA AGM batteries.
- Two voltage level recharge meeting the IU characteristic.
- Restricted charging to reduce electrolyte consumption and extend the life of VRLA batteries.
- Temperature compensation: to avoid excessive voltage being applied to the batteries in a high ambient.
- Built-in battery testing to enable predicted failure reports and detect performance degradation.
- Deep battery discharge protection: to prevent over discharging the battery set.
- Low AC ripple current, achieved using a high-frequency battery charger.
- Wide input voltage range, with a rectifier that can work down to less than 40% of its nominal supply rating.

Multi Sentry can be used for a wide range of applications with several customisation options and accessories providing flexibility and a choice of performance levels:

- compatible with capacitive loads – without any reduction in active power (0.9 lead to 0.9 lag).
- multiple operating modes: On-Line, Eco, Smart-Active and Stand-By/Off and frequency conversion.
- PowerShare connections for priority-based load shedding on mains power supply failure.
- cold-start facility to allow the UPS to be switched on even without a mains power supply present.
- extended runtime options using battery extension cabinets.
- battery cabinet temperature sensor option to assist the temperature compensating charger.
- larger battery charger options to optimize recharge times.
- dual input supplies options for added resilience.
- isolation transformer options for Galvanic isolation and neutral connectivity.