Specifications

Galaxy 5000 technical specifications
MGE UPS SYSTEMS SPTC5 500 UK – 09/2005 page
17
Bypass AC source tolerances and transfer conditions
When the bypass AC source is within tolerances, no-break load transfers are possible by switching from the
inverter to the bypass AC input (decoupling) and back (coupling) via the static switch. Bypass AC source
tolerances are defined by the following conditions:
 Voltage:
Un -8% to Un +10% before coupling
Un -20% to Un +15% after coupling.
 Frequency, user set to one of the following values:
± 0.5%, ± 1%, ± 2%, ± 4%, ± 8% (standard default value).
 Phase deviation between the inverter voltage and the bypass AC source ≤ 3°.
Coupling / decoupling
If the bypass AC source is not within tolerances, transfer to the bypass AC input (decoupling) occurs with a
break that can be user set between 13 and 1000 ms. In this case, the user must validate the decoupling
request made by the system.
When the load is on the bypass AC input, the user can transfer back to the inverter by pressing the ON button.
This request must be confirmed. The load is then transferred without a break. Return to the bypass AC input is
possible only by forced decoupling confirmed by the user to protect against the possibility of the bypass AC
source being outside tolerances.
Automatic bypass
No-break transfer
The automatic bypass ensures automatic, no-break switching to the bypass AC input if the control electronics
detect one of the following conditions:
 Load on inverter greater than the permissible rating.
 Battery protection time expired and bypass AC input available.
 Inverter failure.
Static-switch sizing
The static switch is sized to clear most short-circuits and transient current spikes.
Capacity for 400 V (kAmp.)
Rated power of the UPS unit (kVA) 20 30 40 60 80 100 120
Single-UPS unit In peak / In for 20 ms 45 29 22 15 29 23 19
Parallel unit 117 77 58 39 38 30 25
Static-switch protection
 An RC filter protects the static switch against switching overvoltages and lightning strikes.
 Fuses at the inverter output ensure discrimination if a major fault occurs on the inverter output filter.
 Redundant ventilation is standard. It contributes to energy availability in the most critical cases.
Bypass AC source without a neutral - distribution of the neutral
If the bypass AC source does not have a distributed neutral, an isolation transformer (optional) must be used
on the bypass AC input to recreate a local neutral.
Synchronisation conditions for "fast" variations on the bypass AC source
To protect sensitive loads from excessive frequency variations, the inverter does not synchronise directly with
the bypass AC source. The inverter limits the speed of its frequency synchronisation to a maximum value set
by the user (1 Hz/s or 2 Hz/s).
F
b
y
p
as
s AC source
t
frequency
F inverter
limit
Ifdf/dt of the bypass AC source is less than limit
F
bypass AC source
t
frequency
F inverter
limit
Ifdf/dt of the bypass AC source is greater than limit
Fig. 13. Synchronisation conditions for frequency variations.
2.7 External bypass
Galaxy 5000 is equipped with an external (manual) bypass for direct connection of the load to the bypass AC
source, short-circuiting the rectifier/charger-inverter line and the automatic bypass. Transfer is carried out
using three switches (see section 2.1, fig. 2).
A built-in manual bypass exists in each single-UPS unit. In parallel configurations, starting with two units
without redundancy or three units with or without redundancy, the bypass is external, where the standard 150