Signal Output Contacts - ABB RELION REX640 Technical Manual

Basic functions
Figure 61: Static power outputs SPO1...SPO8
3.14.2

Signal output contacts

Signal output contacts are single-pole, single (normally open/form A or change-
over/form C) signal output contacts (SO1, SO2,...) or parallel connected dual
contacts.
The signal output contacts are used for energizing, for example, external low burden
trip relays, auxiliary relays, annunciators and LEDs.
A single signal contact is rated for a continuous current of 5 A. It has a make and
carry for 0.5 seconds at 15 A.
When two contacts are connected in parallel, the relay is of a different design. It has
the make and carry rating of 30 A for 0.5 seconds. This can be applied for energizing
breaker close coil and tripping coil. Due to the limited breaking capacity, a breaker
auxiliary contact can be required to break the circuit.
Static signal outputs (SSO1, SSO2) are light-duty fast binary signal outputs and can
also be used as pulse outputs.
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REX640
Technical Manual