ZN28K-12 Vacuum Circuit Breaker is a three-phase AC 50Hz, rated voltage 12kV indoor switching device component. It is primarily installed in metal-enclosed armored switchgear and is used for the control and protection of electrical facilities in industrial and mining enterprises, power plants, and substations. It is suitable for frequent operation environments.

Product Specifications

Specification Sheet

No.	Name	Unit	Data
1	Rated Voltage	kV	12
2	Rated Frequency	Hz	50
3	Rated Current	A	630/1250/1600/2000/2500/3150
4	Rated Power Frequency Withstand Voltage	kV	48(Across the Contact gaps) / 42(To Ground)
5	Rated Lightning Impulse Withstand Voltage	kV	75
6	Rated Short-Circuit Breaking Current	kA	25/31.5/40
7	Rated Short-Circuit Making Current (Peak)	kA	63/80/100
8	Rated Withstand Current (Peak)	kA	63/80/100
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 Wear Thickness of Contact	mm	≤3

Mechanical Characteristics

No.	Name	Unit	Data
1	Clearance between Moved and Fixed Contact	mm	11±1
2	Contact Overtravel	mm	4±1
3	Average Closing Speed	m/s	0.6±0.2
4	Average Opening Speed (Average Speed of First Opening at 6mm)	m/s	1.2±0.3
5	Rated Contact Pressure	N	3100±200N(25kA/31.5kA) 4800±300N(40kA)
6	Closing Time	ms	30～70
7	Opening Time	ms	30～50
8	Contact Bouncing Duration at Closing Operation	ms	≤3
9	No-Simultaneity of Closing/Opening Operations of 3-Phase	ms	≤2

Product Advantages

ZN28K-12 Vacuum Circuit Breaker has many advantages:

Reliable Performance

Utilizes vacuum arc extinguishing technology, offering strong arc extinguishing capability, the ability to withstand high short-circuit currents, stable breaking performance, and long electrical and mechanical lifespans.

Convenient Operation

Can be installed and used independently or integrated into fixed switchgear or box-type switchgear. The operating mechanism is flexible, enabling both electric and manual operation.

Easy Maintenance

Features a simple structure with fewer components, eliminating the need for regular replacement of insulating oil, thereby reducing maintenance workload and costs.

Wide Application Range

Suitable for industrial and mining enterprises, power plants, and substations, and can be used for controlling and protecting various electrical equipment, especially in frequent operation environments.