VTZ-12T Mine Vacuum Circuit Breaker is a special model developed by Tongzhong Electric for underground mining applications and high-explosion-proof switchgear. With a rated voltage of 12 kV and a rated frequency of AC 50/60 Hz, it is designed to provide safe, reliable, and stable switching and protection for underground power distribution systems.

The circuit breaker adopts a modular operating mechanism, while the mechanical manual closing and opening interfaces are led out from the top, making operation and maintenance more convenient, especially in limited underground spaces. It is suitable for various mining power facilities and applications with high explosion-proof and safety requirements.

The handcart unit can be used together with PJG-10 switchgear, and is also compatible with newly developed combined high-explosion-proof switchgear. The VTZ-12T is mainly designed to replace the VTZ-12MT series permanent magnet vacuum circuit breaker used in mine high-explosion-proof switchgear. It can also serve as a replacement solution for spring-operated vacuum circuit breakers of the same switchgear type, providing a practical solution for equipment replacement, upgrading, and retrofit applications.

Product Specifications

Specification Sheet

No.	Name	Unit	Data
1	Rated Voltage	kV	12
2	Rated Frequency	Hz	50/60
3	Rated current	A	1250
4	Rated power-frequency withstand voltage	kV	48(Across the contact gaps) /42(To Ground)
5	Rated lighting impulse withstand voltage	kV	75
6	Rated short-circuit breaking current	kA	25/31.5
7	Rated-short-circuit making current (peak)	kA	63/80
8	Rated withstand current (peak)	kA	63/80
9	Rated duration of short circuit	s	4
10	Operating cycles at rated short-circuit breaking current	Times	E2
11	Mechanical endurance	Times	10000
12	Standard Operating sequence	-	O-0.3s-CO-180s-CO
13	Allowable wearing thickness of contacts	mm	≤3

Mechanical Characteristics

No.	Name	Unit	Data
1	Clearance between open contacts	mm	9±1
2	Over-travel	mm	3.5±0.5
3	Average closing speed	m/s	0.7±0.2
4	Average opening speed(average speed at 6mm of initial opening)	m/s	1.1±0.2
5	Rated added external contact final force	N	2500±200N(25kA) 3100±200N(31.5kA)
6	Closing time	ms	30~70ms
7	Opening time	ms	20~50ms
8	Contact bouncing duration at closing operation	ms	≤2
9	Closing/opening no-simultaneity of 3-phase contacts	ms	≤2

Product Advantages

VTZ-12T vacuum circuit breaker for in mines has many advantages:

Performance of circuit breaker：

E2-C2-M2

Simple and convenient maintenance:

With modular structure, the replacement of closing and opening coils does not require the removal of other components. Users can easily replace them, and no testing and adjustment is required after replacement, making later operation and maintenance more convenient;

Safe and reliable:

The circuit breaker and the switchgear cabinet can achieve reliable mechanical interlocking to ensure safe operation and protect operators from potential misoperation. The optional electric chassis truck enables remote insertion and withdrawal, supporting unattended operation and improving operational efficiency and safety.

High conductivity:

Reasonable conductive circuit design meets the temperature rise requirements at 1.1 times the rated current, ensuring excellent current-carrying capacity and stable electrical performance. It also helps reduce excessive heating during continuous operation and enhances the overall safety and reliability of the circuit breaker.

Intelligent configuration:

a. A wireless intelligent temperature monitoring solution can be added with a self-powered design to monitor key component temperatures in real time, ensuring safe operation and reducing maintenance.

b. A mechanical characteristic monitoring solution can monitor circuit breaker operating data in real time, helping identify potential problems early and improving equipment reliability.

c. An electric cabinet entry and withdrawal solution supports remote operation, reducing personnel exposure to high-voltage equipment and improving operational safety.

d. Partial discharge detection monitors component aging and insulation conditions in real time, helping identify potential defects and reduce the risk of equipment failure.