Datasheet

37
Characteristic Curves
For normal operation, all 3 bimetallic strips of the overload relay
must be heated. The overload relays 3UA / C are suitable for
protecting motors with phase control. For protecting single-phase
or DC-loads, therefore, all three main conducting paths must be
connected in series. Tripping curve for 3 pole loads is then
applicable. The release current with a 3-pole symmetrical load is
between 105 % and 120 % of the set current.
Tripping characteristics
The current/time curves show the relationship between the
tripping time from cold state and multiples of the set current Ie.
When the relay is at operating temperature and carrying 100 % Ie,
the tripping times are reduced to approximately 25 %. Tripping
curve is applicable to 3-pole loads and 2-pole loads. For single-
pole loads, the tripping curves lie between curves of 3-pole loads
and 2-pole loads.
The above curves are the general characteristics curves; for individual characteristics curves of each rating, please contact our nearest
sales office.