Electrical Standards For Contactors AC1, AC2, AC3, AC4, DC1, DC2 DC3
Electrical Contactors are categorized according to the current making and breaking values for contactors.
This will depend on the following:
The type of load to be controlled (Inductive load, Lighting load, Motor load, Resistive load, Capacitive load) The operating cycle conditions.
For any applications there are different contactors available depending upon load application which every electrical engineer you must know before designing any systems.
You may have often seen the ratings described on contactor name plate depicting various parameters. One of most important to be considered are as described in this article.
AC duty (Alternating Current) for Contactors:
AC-1 : Non-inductive or slightly inductive loads, example: resistive furnaces, heaters
AC-2 : Slip-ring motors: switching off
AC-3 : Squirrel-cage motors: starting, switches off motors during running time
AC-4 : Squirrel-cage motors: starting, plugging, inching
AC-5a : Switching of discharge lamps
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: examples: mixers, blenders
AC-7b : Motor-loads for household appliances: examples: fans, central vacuum
AC-8a : Hermetic refrigerant compressor motor control with manual resetting overloads
AC-8b : Hermetic refrigerant compressor motor control with automatic resetting overloads
AC-12 : Control of resistive loads and solid state loads with opto-coupler isolation
AC-13 : Control of solid state loads with transformer isolation
AC-14 : Control of small electromagnetic loads
AC-15 : Control of A.C. electromagnetic loads
AC-20 : Connecting and disconnecting under no-load conditions
AC-21 : Switching of resistive loads, including moderate overloads
AC-22 : Switching of mixed resistive and inductive loads, including moderate overloads
AC-23 : Switching of motor loads or other highly inductive loads
Direct Current Duties DC1, DC3, DC5:
DC-1 : Non Inductive or slightly inductive loads, resistance furnaces, heaters
DC-3 : Shunt-motors, starting, plugging(1), inching(2), dynamic braking of motors
DC-5 : Series-motors, starting, plugging(1), inching(2), dynamic braking of motors
DC-6 : Switching of incandescent lamps
DC-12 : Control of resistive loads and solid state loads with opto-coupler isolation
DC-13 : Control of D.C. electromagnetics
DC-14 : Control of D.C. electromagnetic loads having economy resistors in the circuit
DC-20 : Connecting and disconnecting under no-load conditions
DC-21 : Switching of resistive loads, including moderate overloads
DC-22 : Switching of mixed resistive and inductive loads, including moderate overloads (i.e. shunt motors)
DC-23 : Switching of highly inductive loads (i.e. series motors)
