ABB PSU6n-X double-stable Relays

Features

• High degree of reliability, even when it has been idle for a long time
• PSU14n.. with mechanical flag type indicator
• 6 / 14 contacts with double interruption
• Contact configuration can be changed with ease
• Different mounting variants
• Wide range of voltage and contact configuration

Design and principle
Basically, the PSU changeover contactors are composed of the same constructional elements as the established contactors type P8n. Two magnet systems are inter- connected by a pivoted element. In the type PSU6n… with 6 free contacts, only one system has contacts; in type PSU14n… with 14 free contacts, both systems have contacts. In each case two contacts are required for changing over the connection of the coils.

The contacts are arranged symmetrically on both sides of the relay coil and armature assembly in two stacks. They are easily accessible and the conversion from N/C to N/O contacts and vice versa is simple. The maximum rated voltage is 250V d.c. or a.c. and the material used is hard silver. The following definitions apply for reset and operate
condition; reset condition – Armature assembly position is away from the base i.e. the upper system has been pulsed and lower system is ready to be pulsed. The flag strips are invisible i.e. white during this condition. Operate condition – Armature assembly position is closer to the base i.e. the lower system has been pulsed and upper system is ready
to be pulsed. The flag strips are visible i.e. red during this condition.

A transparent, incombustible cover with a gasket protects the contacts against dirt. The terminals of the contact stacks themselves permit two wires of 1.5mm diameter maximum to be secured. The terminals on the base for the external wiring have holes with a diameter of 3.8mm. The terminals on the plug-in base can accommodate two wires, each 2 with a cross-section of 2.5mm . Changeover relays must always be mounted with the contact post horizontal, that is with the base on a vertical surface. The plug-in version offers many advantages, both from the point of view of
installation and afterwards for maintenance. It is fitted with locating pegs which prevent it from being inserted the wrong way round. The labelling of the terminals on the base is identical to that on the contact stacks.