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UMA710-2-xx-ISO-xx, Manual.docx
Issued: 11.Jan.2016
12
3.4. The automatic changeover module UMA710
…
3.4.1. The transfer switching device
If the preferred supply fails, the ATICS® ensures the power supply is changed over safely. The switch
contacts are offset on a rotating shaft. This design prevents simultaneous switching of line 1 and line 2. The
switch has three positions:
1 Line 1 switched on
0 Both lines switched off
2 Line 2 switched on
Either line 1 or line 2 can be set as the preferred line
In the normal condition (fault-free operation) the preferred supply is connected. The ATICS® will
switch to the redundant line if:
– the preferred line fails
– the "TEST" button is pressed
– a digital input is configured to "TEST" and this input is enabled
– the setting "Preferred supply" is reconfigured to the other line
The ATICS® switches from the redundant line back to the preferred line if
– the voltage on the preferred line is restored
- the return transfer delay time T(2->1) has expired and no switching back interlocking function is
enabled
- or immediately after pressing the "RESET" button or when the redundant line fails (even when the
switching-back interlocking function is enabled)
– the setting "Preferred supply" is reconfigured to the other line
– the digital input is configured to "TEST" and this input is reset
– a transfer switching device test is enabled and the test time has expired
With the optional ATICS-ES energy storage device only: The ATICS® changes to switch position
"0" and stays there if the following conditions are simultaneously met:
– Line1 and Line 2 have failed
– Automatic mode is set
– No short-circuit is present downstream of the transfer switching device
– The setting "Load disconnection" is set to "on" and the external ATICS-ES energy storage device
is connected
Malfunction if delay times are not adjusted
The response delay T(on), the return transfer delay time T(2->1), the delay on release T(off)
and the dead time T(0) of the ATICS® are adjustable and must be adjusted to the
requirements of the specific case, the short-circuit-calculation and the requirements of DIN
VDE 0100-710 (VDE 0100 Part 710) Section 710.537.6 automatic changeover devices (see
also chapter "Commissioning, settings and testing").
The factory settings guarantee a changeover period of t = 0.5 seconds and switching back within 10
seconds when voltage is restored on the preferred supply. Therefore, the ATICS® can be used in IT
systems with a requirement for a changeover period t ≤ 0.5 s (IT systems with operating theatre lights,
endoscopic field illumination in operating theatres or other essential sources of light, etc.).
When there is a short circuit downstream of the transfer switching device, the transfer switching device
must not continually change back and forth between the two lines. This can occur when the short-circuit
current is small and the transfer switching device switches faster than the short circuit breaker trips. The
ATICS® monitors the load current downstream of the transfer switching device in order to detect a possible
short circuit. If the preferred line fails and a short-circuit current is detected at the same time, the ATICS®
does not change over immediately but only once the circuit breaker has tripped.
If the ATICS® detects a supply failure or a fault, an alarm appears on the LCD, the "ALARM" LED lights
up, the alarm relay trips (if set) and this alarm is forwarded to other Bender devices (such as an alarm
indicator and test combination) via the BMS bus.
