Tap Changer/Circuit Breaker Timing Test – Overview

Circuit breaker timing testing is essentially a measurement of the operating speed of the breaker—specifically, the duration of its opening (trip) and closing operations. The purpose of the timing test is to determine the response time of the breaker during both opening and closing sequences.

Closing time refers to the interval from the moment a closing command is sent to the closing coil (if present) until the contacts close. These contacts may include the arcing contacts in air circuit breakers, or the main contacts in vacuum or SF6 circuit breakers.
Similarly, opening time is the time from the moment a trip signal is sent to the trip coil until these contacts are fully open.

Timing measurements are typically expressed in milliseconds (ms), though they may also be given in cycles or Hertz depending on the application. These measurements encompass the response time of the relevant coil, the mechanical operation time of the mechanism, and the moment of physical contact closure or separation.

Importance of Tap Changer/Circuit Breaker Timing Tests

Timing tests are critical in assessing the condition of a circuit breaker—particularly after maintenance, component replacement, factory reset adjustment, major overhaul, or corrective action beyond routine preventive maintenance.

The most common and significant issues that timing tests can help identify are those related to the operating mechanism. According to industry statistics, over 50% of serious circuit breaker failures originate from mechanical mechanism faults, with approximately 30% resulting from control or auxiliary circuit issues.

Timing and motion analysis can reveal hidden problems in a circuit breaker mechanism that may not be evident through other inspections. These tests can detect anomalies such as:

1. Delayed coil response

2. Inconsistent operation times across phases

3. Mechanical binding or sticking

4. Excessive contact bounce

5. Uneven motion due to worn or misaligned components

JYK-II has its own high-frequency and high-power DC adjustable power supply, which is suitable for mechanical characteristics testing of high-voltage switchgears of various voltage levels such as SF6 Vacuum circuit breaker, GIS cabinet, disconnectors etc., and can also perform low-voltage tests and reclosing tests of switches.

JYK-II Features:

1. The instrument is suitable for all SF6 switchgear with metal contact points, GIS cabinet, vacuum disconnector, oil switches and column switches, contactors, etc.
2. The sampling frequency is 100K, the test accuracy is higher, and the test data is more accurate
3. Sensors: acceleration speed sensor, rotation speed sensor, linear travel sensor and contact sensor, the installation is extremely convenient and simple, can test three-phase speed, time of switch on-switch off, switch off-switch on, switch off-switch on-switch off
4.30A high-power DC output current, LED digital meter displays DC voltage, easy and clear operation
5. Trigger mode: internal trigger, external trigger, sensor trigger and manual trigger
6. Energy storage power output: the instrument can provide adjustable energy storage with a maximum starting current of 30A
After the power supply is connected at one time, it can automatically control the motor energy storage without reversing the line.
7. Lock release power supply: directly replace the on-site DC power supply, release the opening and closing lock, and facilitate the completion of the switch test
8. The host has a large screen, direct-transparent, wide-temperature backlight LCD, and the contrast is electronically adjusted. Perfect full Chinese menu prompts operation, switch action once, display all data and waveform map
9. The host can store 1000 groups of on-site opening and closing test results, the real-time clock in the machine,
It is convenient to archive and save the test date and time; the USB interface is used for data transfer and program upgrade. RS232 interface, can be used for online operation (optional)
10. The instrument has a powerful data analysis function, which can analyze various mechanical characteristics of the circuit breaker.
Indicator parameters for effective analysis. Built-in fast micro-printer to print all data and maps
11. The instrument has the function of testing the running-in life of switchgear such as circuit breakers and isolating switches, and it can be used for multiple purposes.

JYK-II Technical Specification

Test Item	Test Range	Min.Resolution	Accuracy
Time Testing	0 ~ 8000.0ms	0.01ms	≤ 0.01% rdg ± 0.1ms
	8000.0ms ~ 64000.0ms	0.1ms	≤ 0.01% rdg ± 0.1ms
Speed Testing	0 ~ 20.00m/s	0.01m/s	≤ 1% reading ± 0.01m/s
Travel Testing	0 ~ 1000.0mm	0.1mm	≤ 1% reading ± 0.1mm
Coil Current	Test rang: 40.00A; Resolution 0.01A
Coil Resistance	Test rang: 27.0Ω; Resolution 0.1Ω
Output Power	DC0~270V adjustable/30A; Resolution 1V, deviation ≤ 1% rdg ± 1V
Insulation Resistance	> 2.0MΩ
Power Supply	AC220V±10%, 50Hz ± 1Hz
Volume	L360mm * W240mm * H210mm
Net weight	7kg

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