A contactor is an electrical device that is used for switching an electrical circuit on or off. … These contacts are in most cases normally open and provide operating power to the load when the contactor coil is energized. Contactors are most commonly used for controlling electric motors. There are different types of contacts in a contractor. Auxiliary contact, Power contacts. The power contact has two types stationary and movable contact. 

Standard Contactor

There are two different types of coil in the contactors (AC or DC ) also there are AC Contactor And DC Contactor which refers to contact 

Safety Contactor

Safety contactor has auxiliary contacts permanently connected to the contactors. This feature avoids the possibility of the auxiliary contacts becoming separated from the contactor due to environmental causes such as shock and vibration. The normal contactor has both snap-on and snap-off auxiliary contacts.

Miniature Contactors

The mini contactor is a type of power contactor that is similar to the standard contactors in terms of operation but is smaller in size. It is suitable for applications where space saving is important. A mini contactor is used for switching motors up to 5.5 kW. Or they may use for lighting

Capacitor-Switching Contactors

Capacitor switching application leads to a very high current peak at capacitor energization

Capacitor switching contactors are fitted with early make contacts and damping resistors.

Auxiliary contact

Auxiliary contact is the contact in the auxiliary circuit that is operated mechanically. It is physically linked to the main contacts and activated at the same time. It does not carry so much current. Auxiliary contact is also referred to as supplementary contact or control contact.

NEMA Size

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NEMA SIZE	CONTINUS Amp Rating	HP 230v ac	HP 460v ac
00	9	1	2
0	18	3	5
1	27	5	10
2	45	15	25
3	90	30	50
4	135	50	100
5	270	100	200
6	540	200	400
7	810	300	600
8	1215	450	900
9	2250	800	1600

IEC AC/DC duty for Contactors:

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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˙transfomers
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	ontrol of resisitive loads and solid state loads with˙opto-coupler isolation
AC-13	ontrol of solid state loads with transformer isolation
AC-14	ontrol of small˙electromagnetic˙loads
AC-15	control of A.c electromagnetic loads
AC-20	onnecting 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
A	“Protection of circuits, with no rated short-time withstand current”
B	“Protection of circuits, with a rated short-time withstand current”
DC-1	“Non Inductive or slightly inductive loads, resistance furnaces, heaters”
DC-3	“Shunt-motors, starting, plugging(1), inching(2), dynamic breaking of motors”
DC-5	“Series-motors, starting, plugging(1), inching(2), dynamic breaking of motors”
DC-6	-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)