Riello UPS Multi Sentry 160 MST, Installation And Use Manual

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D
IFFERENTIAL
In the absence of an input separating transformer, the neutral from the mains power supply is connected to the neutral of the
UPS output. This way the neutral regime of the equipment is not modified.
THE INPUT NEUTRAL IS CONNECTED TO THE OUTPUT NEUTRAL THE DISTRIBUTION SYSTEM THAT POWERS THE
UPS IS NOT MODIFIED BY THE UPS
CAUTION: make sure that the equipment is connected correctly to the input neutral, or else damages to the
UPS may be caused.
The circuit neutral is only affected if an isolating transformer is present or the UPS is operating with the neutral
disconnected upstream.
DUAL INPUT versions: the neutral for the input line and bypass line are shared inside the device.
A single differential switch must be fitted upstream of the point at which the line divides to supply the trip switch-
protected rectifier and bypass inputs for the UPS. See following diagram:
PARALLEL versions: In order to prevent false activations where several machines are connected in parallel, a
single differential switch should be fitted upstream of the entire system. See following diagram:
When operating from mains power, a differential switch located at the input can intervene as the output circuit is not isolated
from the input circuit. Anyhow, other differential switches can be inserted at the output, possibly coordinated with the switches at
the input.
The differential switch located upstream must have the following features:
 differential current adjusted to the sum of the UPS + load. we strongly recommend maintaining an adequate margin to
avoid delayed actuation (300mA minimum current)
 type B
 delay greater than or equal to 0,1s