Phase Failure; Earth Fault Detection; Reclosing - Eaton zeb XTOE Handbuch

2.3.3 Phase failure

2.3.4 Earth fault detection

2.3.5 Reclosing

ZEB overload relays are phase-loss sensitive.
In the event of a phase loss, i.e. a phase imbalance f 50 % causes a trip of
10 seconds ±2 %.
￫
If a ZEB relay is to monitor an AC motor, the current must be
fed on all three poles in order to prevent early tripping.
DC motors cannot be monitored.
DANGER

The device settings of the ZEB allows a deactivation of the
phase lost sensitivity (￫ section 3.1.2, "Device settings",
page 41).
When using the ZEB overload relay to protect motor in
potentially explosive environment, do not deactivate the phase
lost sensitivity to avoid a potential motor overheating.
The ground fault variant (ZEB...-...-GF) of the ZEB enables the activation of a
ground fault monitoring function via a DIP switch.
￫
The ground fault detection function is only active while the
motor is running.
After a trip, the electric motor must first cool down from the heat produced
by the overload before it can be switched on again.
The ZEB overload relay has a thermal memory implemented in the electronic
release so that this is ensured.
The ZEB has the two operating modes "manual reset" and "automatic
reset" for the restart of the motor after an overload.
• In "Manual reset" mode the ZEB overload relay can be reset without a
significant time delay (recovery time = 2 seconds).
• It is not allowed to use the automatic reset if the ZEB overload relay is
used for protecting motor in a potential explosive atmosphere.
ZEB (XTOE, C440) 11/16 MN03402007Z-DE/EN www.eaton.com
2 Engineering
2.3 Tripping characteristics
33