Siemens ECOFAST Manual page 40

3.7.2 Behavior in the event of a power failure
24 V DC voltage supply (AS-i) non-switched
(yellow AS-i cable)
This voltage is constantly available. It is required for:
– supplying the electronics in the motor starter
– interrogating the auxiliary contacts
The voltage is not disconnected in the event of an emergency stop or safety
shutdown.
Behavior in the event of undervoltage (24 V DC < 18.5 V) and power failure:
• In the event of prolonged undervoltage or power failure > 20 ms the swit-
ching elements and the brake output are disconnected.
• When the supply is restored, the disconnection command and the associated
signal bits and error bits are acknowledged automatically.
24 V DC voltage supply (AUX PWR) switched
(black AS-i cable)
This voltage is not constantly available. It is only required for:
– driving the switching elements, e.g. a contactor
The voltage can be disconnected in the event of an emergency stop or
safety shutdown (category 1 according to EN 954-1), so that all switching
elements are safely disconnected with the connected motors.
Behavior in the event of undervoltage (24 V DC < 18.5 V) and power failure:
• In the event of prolonged undervoltage or power failure > 20 ms the swit-
ching elements and the brake output are disconnected.
• When the supply is restored, the disconnection command and the associated
signal bits and error bits are acknowledged automatically.
ECOFAST Motor Starters
GWA 4NEB 950 0562-12
Wiring and interfaces
3-15