Utilization Categories
The contactors are designed to switch AC or DC loads. The IEC 60947-4-1 and UL 60947–4–1 standards define the utilization categories for a contactor .
The table below provides the definition of the AC utilization categories:
|
Term |
Definition |
|---|---|
|
AC–1 |
Non–inductive or slightly inductive loads, resistance furnaces |
|
AC–2 |
Slip–ring motors: starting, switching off |
|
AC–3 |
Squirrel–cage motors: starting, switching off motors during running, reversing |
|
AC–3e |
Squirrel-cage motors with higher locked rotor current: starting, switching off motors during running, reversing |
|
AC–4 |
Squirrel–cage motors: starting, plugging, inching |
|
AC–5a |
Switching of electric discharge lamp controls |
|
AC–5b |
Switching of incandescent lamps |
|
AC–6a |
Switching of transformers |
|
AC–6b |
Switching of capacitor banks |
|
AC–7a |
Slightly inductive loads in household appliances and similar applications |
|
AC–7b |
Motor–loads for household applications |
|
AC–8a |
Hermetic refrigerant compressor motor control with manual resetting of overload releases |
|
AC–8b |
Hermetic refrigerant compressor motor control with automatic resetting of overload releases |
The table below provides the definition of the DC utilization categories:
|
Term |
Definition |
|---|---|
|
DC-1 |
Non-inductive or slightly inductive loads |
|
DC-3 |
Shunt-motors: starting, plugging, inching, dynamic breaking of DC motors |
|
DC-5 |
Series-motors: starting, plugging, inching, dynamic breaking of DC motors |