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With a contactor we can control the power connection to the motor (power on/off). A typical AC contactor comes with 4 terminals aside (L1,L2,L3,A).

'A' has A1,A2 terminals which are of the magnetizing coil. By magnetizing & demagnetizing A1-A2 coil, power line connections to motor can either be made or broken. This is a simple DOL (Direct On Line) application.

Further, reverse/forward circuits and star-delta circuits can be constructed based on the requirement.

A contactor's role in whatever application is 'making or breaking' the contact.

The coil supply can either be AC or DC.

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11y ago
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11y ago

Look at the amount of current that the contactor plate can handle. The motor current must be lower than the current that the contactor can handle.

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Q: How do you select contactor for motor?
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How to choose rating of contactor in star delta starter?

As well as motors, contactors also have kW and Ampere ratings. Have a look on the name plate of your motor and you will see its maximum current draw (amps). Select a contactor with a current rating greater than this.


What is the difference between an definite purpose contactor and a lighting sontactor?

A definite purpose contactor is designed (and rated) for a specific load. So a lighting contactor is one example of a definite purpose contactor. A motor starter contactor is another example. So, a lighting contactor is a definite purpose contactor, but a definite purpose contactor is not necessarily a lighting contactor (it might be a motor starter, for instance).


What causes a contactor for a 3 phase motor to kick in and out. Tha contactor was replaced with the heaters and still kicks in amd out?

See discuss question below.


Why rotor contactor in external resistance of slipring motor connected in delta?

rotor contactor are used to cut the resistance in slip-ring motor connected through resistance box. resistance is proportional to torque. so by controlling rotor contactor resistance can be controlled and hence torque can be controlled. for more information check torque and speed characteristic of wound motor.


What is wye-delta motor control?

It is a type of starter that allows a motor to be started across the line by starting the motor with a reduced inrush current. The motor is started in a wye configuration until it gets up to speed and then a timer drops the wye contactor out a draws the delta configured contactor in. The motor then operates in a delta wired configuration.

Related questions

What is the difference between a motor starter and a contactor?

Motor started will have overloads the contactor connect es line voltage.


How does magnetic contactor operate?

explain me about the contactor works with examples. if i want to control a motor with contactor. and how i can use contactor in loops with over load and circuit breakers.


How to choose rating of contactor in star delta starter?

As well as motors, contactors also have kW and Ampere ratings. Have a look on the name plate of your motor and you will see its maximum current draw (amps). Select a contactor with a current rating greater than this.


How do you wire a relay to a motor contactor?

One way is to use the auxiliary contacts on the motor contactor to close a separate source supply to drive an auxiliary relay.


Which side of a motor contactor should the overload contact be placed?

On the load side of the contactor. T1,T2,T3.


How do you make a 30HP three phase motor connection?

From the bottom of the motor contactor's heater block you connect the motor's leads to T1, T2 and T3. If the motor rotates in the wrong direction reverse any two leads on the bottom of the motor's contactor heater block.


What is the difference between an definite purpose contactor and a lighting sontactor?

A definite purpose contactor is designed (and rated) for a specific load. So a lighting contactor is one example of a definite purpose contactor. A motor starter contactor is another example. So, a lighting contactor is a definite purpose contactor, but a definite purpose contactor is not necessarily a lighting contactor (it might be a motor starter, for instance).


What component starts the indoor fan motor in an air conditioner?

contactor


What causes a contactor for a 3 phase motor to kick in and out. Tha contactor was replaced with the heaters and still kicks in amd out?

See discuss question below.


Why star delta timer required for motor?

The timer is used to give the motor time to reach its running speed at the star voltage. Once the timer times out the star contactor drops out and the delta contactor pulls in.


Why rotor contactor in external resistance of slipring motor connected in delta?

rotor contactor are used to cut the resistance in slip-ring motor connected through resistance box. resistance is proportional to torque. so by controlling rotor contactor resistance can be controlled and hence torque can be controlled. for more information check torque and speed characteristic of wound motor.


Why use link in star contactor?

The link in the star contactor is used to form the star point of three of the motor leads. On most star wound motors the star point is inside the motor windings. On a motor that can be used for star delta starting it is a six wire motor. The star point winding depends on the contactor to tie the coil ends together externally in the control panel of the star delta starter.