Guidelines on Operation of Star/Delta Starter

1. Before energizing the motor feeder, check movement of each contactor by means of manually pressing the moving bridge.
2. Ensure that all the connections are fully tighten as per the required force (NM) value of each screw/bolt.
3. Ensure that shorting links at star contactor are intact & tighten.
4. Ensure that control fuse carrier with HRC fuse is intact and in case of MCB, it is in ‘ON’ position.
5. Incase terminal provided for external additional interlock have not been used, a shorting link must be provided.
6. Incase terminal provided for start/ stop operation through BMS have not been used, do not provide shorting link between these two terminals.

Philosophy of Operation

• Start push button gives command to Star/Delta timer.
• The same command goes to Star contactor through NC contacts of timer and Delta contactor.
• After energizing Star contactor, it gives start command to Line contactor through NO contact of Star contactor
• Once Line contactor get energize, it gets sealing command from its own NO contacts.
• Motor starts on Star connections.
• After prefix time the timer disconnect control supply to Star contactor and give supply to Delta contactor through NC contact of Star contactor, now motor runs on Delta circuit.

Starting Sequence

• Disconnect both the cables at motor end.
• Energize the motor feeder and check the availability of power supply at cables end already disconnected from motor after completion of timer sequence.
• Re-connect the cables at motor end and start using the motor starter for your normal use.

Troubleshooting a Star/Delta Starter

Scenerio-1

Starter does not energize after pressing start button?

Solution:

• Check the availability of supply
• Check the control fuse is intact or control MCB is in ‘ON’ position
• Check the additional interlocks are in working condition. Provide jumper at terminals, in case these are not used
• Check single phasing preventing device (if provided) is in healthy condition
• Check overload relay in healthy condition. press reset button in case its on manual mode
• Check for Auto/Manual selector switch (if provided) is in manual mode

Scenario-2

The starter operated, but the motor fails to start?

Solution: Several potential reasons could be causing this issue:

• The shorting power links at the Star contactor are missing- Check and ensure that the shorting power links at the Star contactor are properly installed. If they are missing, insert them securely to complete the connection.
• The Star/delta timer is not functioning correctly- Inspect the Star/delta timer for any malfunctions. Reset the timer or replace it if necessary to restore its proper functionality.
• There are wrong connections at the motor end- Verify the motor connections thoroughly. If any connections are found missing, make the necessary connections according to the motor’s specifications and guidelines.

Scenerio-3

Motor take start in Star connections but stops in Delta?

Solution:

There are wrong connections at the motor end- Verify the motor connections thoroughly. If any connections are found missing, make the necessary connections according to the motor’s specifications and guidelines.

Scenerio-4

Motor take start in Star and gives humming noise in delta?

Solution:

There are wrong connections at the motor end- Verify the motor connections thoroughly

Scenerio-5

Motor take start in Star connections but stops in Delta?

Solution:

There are wrong connections at the motor end- Verify the motor connections thoroughly

Scenerio-6

Motor starts on Star for some time but short circuit happened after that and contacts of Star & Delta contactors got welded.

Solution:

There are wrong connections at the motor end- Verify the motor connections thoroughly.