Chapter 2
System Description
Version: A.02
Product Description ENS31
Page 5 of 20
Issue: 20.09.2005
2 System
Description
2.1
Principles of functioning
The ENS31 automatic isolation unit continually monitors
•
overvoltage and undervoltage
•
frequency deviation
•
impedance jumps
in the public electricity supply.
In the event of faults in the mains supply, the ENS31 interrupts the feed-
ing of electricity in the mains to prevent island effects.
The contact-based disconnection is initiated by externally provided con-
tactors with positively driven NC contacts. These contactors are controlled
in two channels by the ENS31 via relays Rel1 and Rel2. Request for the
switching status of the external contactors occurs via two acknowledge-
ment inputs.
After switching on, Contactor 1 is activated first and Contactor 2 is only
enabled after reaching and testing the switching status.
Note
The ENS31 cannot be switched on without the acknowledgement inputs
being correctly wired.
The safety functions are executed in a 3-channel system, whereby each
channel measures the mains voltage, mains frequency, mains impedance
and the voltage of another channel independently.
The channels monitor each other mutually (refer to the error protection in
accordance with DIN VDE 0126) to increase error protection. Therefore,
recurrent tests can be dispensed with.
Note
Further information on the principles of functioning is available on our
Internet site at
www.ufegmbh.de
.
