Specifications

Galaxy 5000 technical specifications

MGE UPS SYSTEMS SPTC5 500 UK – 09/2005 page

Direct thermal monitoring of the sixpack IGBT modules

A sensor placed directly on the base of the rectifier and inverter sixpack modules monitors the cooling system.

This allows an early detection of a malfunction that, so far, could have been destructive. (i.e. : body on the

heatsink). Then, the UPS transfers without a break to the bypass AC input and sends an alarm to the user.

Avoiding the component to be damaged greatly improves the availability of the UPS.

Sensor on base of

sixpack IGBT

module.

Sixpack IGBT

components

Fig. 12. Direct thermal monitoring of the sixpack IGBT modules.

Cold-start mode

A standard function of Galaxy 5000 is the cold-start mode where the UPS starts on battery power if normal AC

power is not available. This mode is initiated by buttons on the control panel.

Once started, the UPS operates on battery power until the end of the backup time or on genset power that

comes on line to replace the AC power.

This start mode is possible only when the UPS has been started at least once on normal AC power to charge

the chemical capacitors of the DC bus. Subsequently, as long as the control electronics remain supplied

(sleep mode) and the battery circuit breaker is closed, the UPS can start on battery power (if not already

depleted).

Backfeed protection

There is sufficient space in Galaxy 5000 for two, optional, electromechanical contactors on the normal and

bypass AC lines. These contactors cut the lines upstream of the UPS if AC power fails. This avoids voltage

backfeed on the AC lines if one or more SCRs in the static switches fault (short-circuit).

The contactors are supplied directly by the lines.

With the backfeed option, the permissible input voltage on the normal AC input is between 342 and 470 V.

This restriction is due to the coil of the contactor used.

This option is mandatory for UPSs that must comply with standard EN60950.

Frequency-converter option

Single-UPS units in the Galaxy 5000 range can be used as frequency converters. In this case, the manual

bypass is disabled.

2.6 Automatic bypass

Bypass AC source

The bypass AC source supplies the bypass AC input, generally via a three-phase outgoer + N in the low-

voltage switchboard upstream, separate from the outgoer supplying the normal AC input. It can operate

without a neutral.

However, both AC inputs (normal and bypass) can be supplied by the same outgoer (second cable).

Operation on the bypass AC input is a downgraded mode (except in ECO mode) indicated by an orange LED

on the control panel.