Disconnect the relay from supply

The relay is set by turning the knurled screw, which is fitted with an automatic notching device. The set value is read off the scale by means of the pointer slide. The tripping current depends on the operating conditions of the particular installation.


The relay should only be mounted in a place which is free from vibration, moisture, dust and acid vapours.
The ambient temperautre may be between – 30 ° and + 60 ° C.
The relays should be mounted vertically.
The current connections should be made with great care and screws tightened up fully.

When installing the relays, make sure that adequate clearances and creepage distances are allowed between the relay connections and the mounting supports.

Special instructions for bar-mounted relays (models 42 to 64).

These relays have a fixed air-gap in their core (high setting range).
To avoid magnetic shunting, they must be mounted a definite distance Z from any iron or steel backing.

Setting range Distance Z
1000 – 2000 Amp. 24mm
1500 – 3000 Amp. 32mm
2000 – 5000 Amp. 80mm
3000 – 6000 Amp. 100mm

Testing and maintenance

It is advisable, when commissioning the relays, to subject them to a current test prior to adjusting the setting, so as to be sure that they will trip properly when needed.
In service the relays do not require any maintenance. In particular. They must NOT be oiled. The relays should be dusted occasionally. When ordering spare parts or in the event of queries, please quote the works serial number of the relay concerned.