Eaton Power Xpert PXR 10, Руководство пользователя

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4 Protection settings
4.1 Overload release
PXR Electronic trip unit 01/21 MN012005EN www.eaton.com
25
4 Protection settings
The protection settings of the PXR trip unit are designed so that they can be
easily adapted to any application.
The following settings can be configured, independently of one another:
• Overload release I
r
• Time lag t
r
• Short-time delayed short-circuit release I
sd
,
• Duration of short-time delay t
sd
,
• Instantaneous trip I
i
,
• Ground-fault trip I
g
,
• Ground-fault delay time t
g
.
The settings can be adjusted using the rotary switches (on the PXR10 and
PXR20 trip units) or the display (on the PXR25 trip unit) at the front of the trip
unit.
Additional options can be selected via the display (on the PXR25 trip unit
only), the navigation buttons, the
Power Xpert Protection Manager
configuration software (on all PXR variants) or the communication link.
The minimum and maximum protection settings vary depending on the
frame size, rated operational current and version of the trip unit.
4.1 Overload release
Each PXR trip unit offers a variety of settings for theoverload release I
r
.
The settings range from 40 % to 100 % of the rated operational current I
n
.
Depending on the version, the duration of the time lag t
r
is up to 20 seconds.
The value corresponds to the entire trip time if the current is equal to six
times of I
r
. The reference value for the duration is the upper end of the
tolerance range. This ensures that the maximum duration is not exceeded.
If the infinity setting
( ? ) is selected, the overload release will be deactivated.
As soon as an overload causes the circuit breaker to trip, the LONG indicator
will light up, provided that auxiliary power is available (on the PXR20), or a
message will appear on the display (on the PXR25).
￫
Before putting the circuit breaker into service, the protection
settings of each trip unit should be set to the values specified by
the technician responsible for installing the circuit breaker.