How to install ABB VSC vacuum contactor?

Fasteners: Check if the screws have misplaced color codes (there are color codes at the factory). If there is no looseness, there is no need to tighten them again.

Lubrication of moving parts: KLUBER NB52 grease is recommended.

Auxiliary switch: Manually operate several times to confirm that the contacts are open and closed normally without any burn marks.

Emergency disconnection test: Use an Allen wrench to turn clockwise by about 30 degrees (torque 5Nm), and it should be able to reliably disconnect.

6.3 Vacuum arc extinguishing chamber inspection

The vacuum arc extinguishing chamber is a sealed component that does not require maintenance during normal use. Vacuum degree testing is only required in the following situations:

Suspected of being impacted by external forces

Put into operation after storage for over 20 years

Abnormal appearance after disconnecting the short-circuit current

Overtravel measurement (to determine contact wear): Measure the overtravel "M" (the distance further compressed by the moving contact) of each phase when the contactor is closed. If any phase overtravel is less than 0.5mm, the arc extinguishing chamber component must be replaced (the nut cannot be adjusted).

Vacuum degree detection: Use VIDAR vacuum tester to test in the open state. Test voltage: 7.2kV contactor uses 25kV DC, 12kV contactor uses 40kV DC. Connect the high-voltage end of the tester to the ungrounded end of the arc extinguishing chamber, and ground the frame. The normal vacuum degree should be better than 1.33 × 10 ⁻ ³ Pa.

6.4 Fuse Replacement (with Fuse Support Model)

VSC can be combined with current limiting fuses to provide short-circuit protection. The fuse holder is compatible with DIN (length 442mm) or BS (553mm) standards and comes with an adapter for short fuse links (192mm, 292mm, 235mm, 305mm, 454mm).

Replacement steps:

Shake the contactor out to the test position or extract it from the cabinet to confirm the disconnection.

Remove the panel screws and open the panel.

For the 12kV model, remove the internal protective panel.

Use a specialized tool (card spring opener) to release the fuse card spring.

Remove the fuse and check if the fuse indicator pin pops out.

When installing a new fuse, ensure that the firing pin is facing in the opposite direction of the contactor's plum blossom contact finger (towards the release mechanism).

If using an adapter, select the correct model by length and secure it with a clamp.

Reset the panel, push the contactor back to the working position, and perform a functional test.

Attention: When any phase fuse is missing or the fuse has already blown, the electrical interlock will prevent the contactor from closing.

Troubleshooting Guide

7.1 Contactor unable to close

Possible cause inspection and resolution

The power module is not ready and waits for 15 seconds to start after powering on; Check if the auxiliary power supply is connected to KM1-1/KM1-2 and if the voltage range is compliant (24-250V AC/DC).

Check if the DO1 ready signal is output when the capacitor voltage is insufficient; Measure the terminal voltage of the capacitor (normally close to the rated value). The module may need to be replaced.

Check the fuse status indicator for missing or blown fuses; Replace the fuse.

Confirm the position interlock of the handcart in the working or testing position (pull-out type); Check if the BT1/BT2 position contacts are normal.

Check if the voltage of the UV input (KM1-1/12) is normal when the undervoltage trip is not reset (DCO); Is the delay setting correct.

The locking electromagnet is not powered, and the voltage of the electromagnet coil is measured; Check if the auxiliary circuit aviation plug is securely plugged in.

The closing command has not been delivered to measure whether there is a pulse (DCO) of ≥ 30ms or a continuous high level (SCO) between terminals KM1-7/8.

7.2 Contactor unable to open

Possible cause inspection and resolution

Missing opening command check KM1-9/10 (DCO) pulse; For SCO, try cutting off the auxiliary power supply.

The permanent magnet mechanism is stuck and needs to be manually opened using an emergency opening device. If it still cannot be opened, it needs to be returned to the factory for maintenance.

The insufficient energy of the capacitor also relies on the discharge of the capacitor to open the circuit. Check the power module.

7.3 Immediately trip the contactor after closing

Check if there is a blown fuse (phase loss protection action).

Check if there are both closing and opening commands (anti bounce function is in effect).

Check if the undervoltage trip circuit has malfunctioned (due to voltage fluctuations or short set delay).

7.4 Auxiliary signal abnormality

DO1 not outputting: The power module self-test failed, or the coil was disconnected (which can be determined by measuring the coil resistance, and should have a certain resistance value normally).

DO2 alarm: Module temperature too high (improve ventilation) or capacitor aging (replace module).

7.5 Manual emergency disconnection is invalid

Confirm to use an M8 hex wrench and turn it clockwise by about 30 ° with a torque of 5Nm. Excessive rotation may damage the mechanism.