Hager ER120 - what does it do?

Hager ER120 - what does it do?
Posted by endeavour on 09 Apr, 2024 14:45
I'm not sure I understand the wiring diagram on the front of the unit, nor what the switch is meant to do. Could anybody explain how it works?

Also is the switch meant to move, because it seems to be stuck in the auto position?

Thanks!

#1 Reply
Posted by Manul on 09 Apr, 2024 20:10
Seems to be a relay with two pairs of contancs, NO (normally open) and NC (normally closed). Operated by energizing A1 and A2 with 230V AC. Switch is probably a manual override, for testing purposes, not sure.

#2 Reply
Posted by tooki on 09 Apr, 2024 20:32
Manul is exactly right. The “auto” position is just the “normal” position (i.e. it operates as a relay controlled by the coil), while “on” and “off” manually override it.

#3 Reply
Posted by MarkT on 09 Apr, 2024 22:31
I suspect its useful for maintenance/servicing of equipment as an override to the normal operating mode. Hopefully the lever is sprung to return to centre so you can't accidentally leave things overriden...

#4 Reply
Posted by tooki on 09 Apr, 2024 23:54
Quote from: MarkT on 09 Apr, 2024 22:31
I suspect its useful for maintenance/servicing of equipment as an override to the normal operating mode. Hopefully the lever is sprung to return to centre so you can't accidentally leave things overriden...
Based on their current catalog, I suspect the switch is specifically designed to stay on or off, which is the point of the switch: it’s an override.

They make other models which return from on to auto, but manual off stays off.