MANUAL MOTOR STARTER GUIDE
APRIL 19 27/80
2.4.6.4 Shunt release AA1
The AA1 shunt release has a different direction of action to the UA1. The tripping occurs when a supply current is ap-
plied. Thereby the anchor is attracted and rotates the transfer lever via the slider. In accordance with the basic IEC
60947-1 standard, the manual motor starter must be switched off by the AA1 if the supply voltage of the shunt re-
lease measured during the tripping operation remains between 70% and 110% of the rated control circuit supply
voltage.
2.4.6.5 Under-voltage release UA1
The UA1 under-voltage release releases the manual motor starter or prevents it from being switched on when its volt-
age supply is interrupted. This can be used in emergency switching circuits or can prevent an automatic restart after
voltage interruption.
The basic IEC 60947-1 standard defines the following limits of operation for under-voltage releases:
− When 35% of the rated voltage is applied to the UA1, it must not be possible to switch the manual motor
starter on
− When 85% of the rated voltage is applied to the UA1, it must not be possible to switch the manual motor
starter on
− If the rated voltage goes down, a switched-on manual motor starter must be switched off, over the UA1, at a
voltage between 70% and 35% of the rated voltage
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