contactor connection

[Rajan Shakti]

in a 3 pole contactor suppose three wire coming in l1 l2 l3 and two control signal r1 and r2 what is the use of one no or nc contact can anyone help

 

[malcolmsanford]

A simple example of this would be the N/C contact.

If a contactor is designed to run a motor then when it is engerigised the N/O contacts become Closed allowing the voltage through same as a switch.

If for instance the motor is remote and without an operator you could wire a light or a buzzer to a N/C point. This N/C point would open when the motor is running, but if it tripped out or de-energises the contactor the contact makes, like a switch and would activate you light/buzzer

 

[Dayo1959]

The no or nc contact can show the status of the contactor, whether it is energised or not, amongst other things

 

[Robotstar5]

You can use the N/O contact to latch the contactor in e.g. pushbutton start/stop circuit.

 

[clematis432]

"The two control signals R1 and R2" you speak of I would think are actually the coil connections. As others say the n/o and n/c auxiliary contacts can be used for many purposes. Most contactors use a n/o for retention of the contactor coil.
Just a thought, should this thread be on the Commercial and Industrial section ? Maybe more informed answers there, although previous posts have answered the question clearly enough.

 

[44ALLAN]

It could also be the overload relay he's talking about attached to the bottom of a contactor where the n/c contact is used in the control circuit for tripping purposes.

 

[clematis432]

It could also be the overload relay he's talking about attached to the bottom of a contactor where the n/c contact is used in the control circuit for tripping purposes.

Don,t think he mentioned an overload relay attached to the contactor. Most contactors don,t have overloads attached to them, although you can connect some types, to the bottom of the contactor as you say.

 

[44ALLAN]

Don,t think he mentioned an overload relay attached to the contactor. Most contactors don,t have overloads attached to them, although you can connect some types, to the bottom of the contactor as you say.

True.
Reading it again it does look like he's talking about auxilliary contacts

 

[Robotstar5]

"The two control signals R1 and R2" you speak of I would think are actually the coil connections.

Usually marked A1 & A2 on most contactors I've used.