Automatic Starter: Troubleshooting and Rectification of Automatic Starter

(Last Updated On: 18/04/2018)

An automatic starter is used to start the electric motor of an air compressor.

These starters are mainly of two types one is an Automatic starter and another is Manual operated starter.

Automatic Starter is Contactor type and mostly used in all Engineering units nowadays.

In Air Compressor Engineering, accessories are very important to keep the machine in running condition.

Automatic Starter (Contactor type) is mainly used to start Electric Motor so the Air Compressor coupled to that motor can be started.

Let’s go for Troubleshooting and Rectification of Automatic Starter (Contactor type)

automatic starter troubleshooting

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  • AUTOMATIC STARTER FAULT: CONTACTOR FAILS TO CLOSE

Reason :-( 01) Coil open circuited.
Rectification :-( 01) Change the coil.
Reason :-( 02) Loose control circuit connections.
Rectification :-( 02) Tighten all the screws.
Reason :-( 03) Voltage too low.
Rectification :-( 03) Improve voltage conditions.
Reason :-( 04) Coil rating wrong.
Rectification :-( 04) Use correct rating coil.
Reason :-( 05) Obstacles in moving contacts carriers movement.
Rectification :-( 05) Remove the obstacles.
 
  • AUTOMATIC STARTER FAULT: FUSES BLOWS DURING STARTING

Reason :-( 01) Fuse rating is too low.
Rectification :-( 01) Use correct rating of fuses. Fuse for DOL Starters should be 3 to 4 times of motor full load current and for Star-Delta 1.5 to 2.5 times.
Reason :-( 02) Short circuit in the system.
Rectification :-( 02) Check and rectify the faulty CCF.
 
  • AUTOMATIC STARTER FAULT: INADVERTENT TRIPPING OF STARTERS

Reason :-( 01) Overload Relay setting low or single phasing
Rectification :-( 01) Check voltage and current drawn by the Electric Motor and adjust Overload Relay to the motor full load current.
Reason :-( 02) Motor takes very long time to accelerate due to very low incoming voltage.
Rectification :-( 02) Improve the voltage condition and use proper size cables.
Reason :-( 03) Motor overloaded.
Rectification :-( 03) Unload the Air Compressor during the starting.
 
  • AUTOMATIC STARTER FAULT: SEVERE CONTACT BURNING OR WELDING

Reason :-( 01) Excessive voltage drop during starting preventing the magnet from closing in one stroke.
Rectification :-( 01) Check the cross-section of the cables from the supply source to the motor.
Reason :-( 02) Insufficient contact pressure.
Rectification :-( 02) Check moving contact spring pressure, change if necessary.
Reason :-( 03) Change over in Star-Delta is too early.
Rectification :-( 03) Increase the timer setting.
 
  • AUTOMATIC STARTER FAULT: NOISY CONTACTOR

Reason :-( 01) Dirty or rusty magnet and armature faces.
Rectification :-( 01) Clean the magnet and armature face with a soft cloth and apply petroleum Jelly.
Reason :-( 02) Restricted movement or friction in magnetic movement.
Rectification :-( 02) Check magnet by hand for free movement.
Reason :-( 03) Intermittent contact on control circuit.
Rectification :-( 03) Check all the contacts and control switches in control circuit for effective contacts.
Reason :-( 04) Magnet and /or armature faces are not true.
Rectification :-( 04) Change magnet and /or armature as the case may be.
Reason :-( 05) Contactor chatter after changing the “No Volt” coil because the moving contactor carrier is fitted in reverse direction.
Rectification :-( 05) Correct the direction.
 
  • AUTOMATIC STARTER FAULT: COIL BURNING

Reason :-( 01) Overvoltage.
Rectification :-( 01) Correct the incoming supply voltage.
Reason :-( 02) Coil rating wrong.
Rectification :-( 02) Use proper rating coil.
Reason :-( 03) Noisy contactor.
Rectification :-( 03) Refer the rectification for noisy contactor as per fault (E).

 

  • AUTOMATIC STARTER FAULT: STARTER FAILS TO OPEN

For this fault, there are three conditions.
(A) The fault occurs, when the supply switch is “Off”.
A reason is a residual magnetism in armature and magnet.
Rectification is, Polish very little or put some punch on the centre line of an armature.
(B) The fault occurs, when “Off” pushbutton pressed.
A reason is, (1) Cover fixing screw is loose.
Rectification is, (1) Tighten the screw fully.
Reason :-( 02) Push button length is short.
Rectification :-( 02) Set the right push button.
 
(C) The fault occurs due to condition A & B
A reason is, (1) Contact tips welded.
Rectification is, (1) Change the defective contacts.
Reason :-( 02) Moving contacts carrier sticky.
Rectification :-( 02) Check the moving contacts carrier and rectify the cause of sticking.
My goal is to keep you informed about the automatic starter and every field of Air Compressor. I hope the post will help you to rectify problems with your automatic starter.

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