Causes of Vacuum Circuit Breaker Failure and How to Solove It

Common Faults of Vacuum Circuit Breakers 1. The Vacuum Level within…

Common Faults of Vacuum Circuit Breakers

1. The Vacuum Level within the Vacuum Bubble is Lessened

The vacuum circuit breaker terminates the flow of current and snuffs out the spark in the vacuum bubble, but it does not have a device to qualitatively and quantitatively evaluate the quality of the vacuum level, thus making vacuum reduction failure a latent problem with much greater potential danger than the detectable fault.

Causes of this Error

ZN63 indoor vacuum circuit breaker

Issues have arisen with the fabrication or creation of the vacuum bubble, and the latter has been observed to have minor leaks.

Additionally, there have been issues with the production of the corrugated tube inside said bubble, resulting in seepage after multiple sessions.

Divide vacuum circuit breakers, for instance those that use an electromagnetic operating mechanism, during operation, as a result of the extended length of the operating link, directly influencing the synchronization, bounce, over-travel characteristics of the switch, thus boosting the speed at which the vacuum is decreased.

2. The Vacuum Circuit Breaker Unable to Open

Depending on the various causes of the breakdown, these failure signs occur: Remote opening is not possible; Manual opening on-site is impossible; In case of emergency, the relay protection activates but disconnecting the circuit breaker is not achievable.

Reasons of this Error

The reason why cause this error is that the opening circuit has been cut off or the initiating coil has snapped. In addition, the voltage of the power source for operation has dropped.

And the conductivity of the initiating coil is higher and the initial force is weaker. When attempting to open, the ejector rod that initiates has warped, leading to a jamming situation and decreased power or the ejector rod that initiates is badly bent and obstructed.

3. The Spring Operating Mechanism Closing Energy Storage Circuit Failure

The opening operation cannot be realized after closing. And the energy storage motor does not stop running, and even causes the motor coil to overheat and damage.

Causes of this Error

The travel switch should be placed lower down so that the tension spring has not been wound up, causing the contacts of the switch to switch off, thereby cutting off the motor power and leaving insufficient energy in the spring to open.

The placement of the trip switch is located on the top so that after the compression spring has been wound, the contact of the trip switch has not changed and the energy storage motor is still running.

Or the trip switch is defective, hence the energy storage motor cannot be shut down.

outdoor pole mounted vacuum circuit breaker

4. Different Periods of Opening and Closing, Large Bounce Value

This failure a hidden fault, and the relevant data must be obtained through the measurement of the characteristic tester.

Reasons of this Error

The mechanics of the circuit breaker body are not satisfactory. Or after numerous cycles, there is an excessive oscillation value in different intervals caused by mechanical issues.

What’s more, the split type circuit breaker has a wide gap between its operating rods. Leading to disparities in the phases when the opening force is sent to the contacts causing dissimilar periods and an excessive bounce value.

Vacuum Circuit Breaker Troubleshooting

The vacuum interrupter to be replaced must pass the vacuum degree test.

Remove the original vacuum interrupter and replace it with a new one. The installation should be vertical.

vacuum circuit breaker with embedded pole

Pay attention to the coaxially of the movable conducting pole. And the arc extinguishing chamber, and do not suffer torsion during operation.

After installing the new vacuum interrupter, the opening distance and over travel (contact stroke) should be measured. 

If it does not meet the requirements, it should be adjusted accordingly:

① adjust the bolt of insulation pull rod to adjust the overtravel;

② The opening distance of arc extinguishing chamber can be adjusted by adjusting the length of moving conducting pole.

The opening and closing speed, three-phase synchronization. Closing bounce and other mechanical characteristics are measured by the power switch comprehensive tester. If they are unqualified, they should be adjusted.

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