FZN25-12 Indoor AC High-Voltage Vacuum Load Switch

The FZN25-12 indoor AC high-voltage vacuum load switch is designed for 12kV, 50Hz three-phase networks, capable of switching load currents and closing short-circuit currents. Rated at 630A with 20/25kA short-time withstand capacity, it features reliable vacuum arc-extinguishing technology. This load switch supports both manual and motorized operation, making it ideal for harsh environments requiring long maintenance intervals and frequent operation. Compliant with GB/T and IEC standards, it provides stable performance in temperatures from -25℃ to +40℃ and altitudes up to 2000m.

product details

Type & Meaning

F	Load Break Switch
Z	Vacuum
N	Indoor
25	Design Serial Number
12	Rated Voltage (kV)
D	Earthing Switch (Optional)
T	Spring Operating Mechanism
630	Rated Current (A)
20	Rated Short-time Withstand Current (kA)

Basic Structure

The FZN25-12 is a frame-assembled load break switch. Moving/fixed contacts in each phase are enclosed in a vacuum interrupter, mounted with conductors on an integral insulator. The interrupter connects to a rear vertical disconnector via conductors. The disconnector is housed in a semi-enclosed insulator fixed to the metal frame. A side-mounted spring operating mechanism extends service life. A removable fuse assembly forms a switch-fuse combination. The frame includes an earthing arm, mechanism, and interlocks. A transparent flame-retardant shield ensures safety, and a bottom earthing contact enables integrated earthing switch versions.
1.Uses vacuum interrupter for strong arc extinction, reliable and safe performance.
2.Integrated load break switch, disconnector, and mechanism for simple one-step operation with visible break; optional earthing switch with interlock.
3.Supports manual/motorized operation with reliable interlocks, simplifying switchgear design.
4.Fully insulated design (SMC supports) with conical insulators and transparent shield, ideal for armored switchgear.
5.Flexible installation (front/side mount), easy maintenance and fuse replacement.

1.Upper contact base of disconnector
2.Insulating support frame
3.Transparent glass shield
4.Metal frame
5.Conductive tube of disconnector
6.Lower contact base of disconnector
7.Vacuum interrupter
8.Lower outlet base of vacuum interrupter
9.Drive unit of vacuum load break switch
10.Fuse
11.Tripping unit
12.Earthing switch
13.Operation hole for earthing switch
14.Cabinet door lock pin
15.Manual trip button
16.Operation hole for charging & closing

product Display

Technical Parameters

1.Main Electrical Technical Parameters

Parameters		Unit	Model
			FZN25-12D/T630	FZRN25-12D/T200
Rated Voltage		kV	12	12
Rated Frequency		Hz	50	50
Rated Current		A	630	200
Rated Breaking Current	Active Load Current	A	630
	Closed-loop Current	A	630
	No-load Transformer Capacity	kVA	1600
	Cable Charging Current	A	10
Rated Transfer Current		A		1700
Rated Short-time Withstand Current (4s)		kA	20(25)
Rated Peak Withstand Current			50(63)
Rated Short-circuit Breaking Current		kA		31.5
Rated Short-circuit Making Current		kA	50(63)
Rated Short-time (1min) Power Frequency Withstand Voltage		kV	42/48
Rated Lightning Impulse Withstand Voltage (Peak)		kV	75/85
Notes: 1) The rated short-circuit duration for the earthing switch is 2 seconds. 2) The 1min power frequency withstand voltage across the interrupter break is 35kV.

2. Main Mechanical Characteristic Parameters

Parameters	Unit	Value	Note
Vacuum interrupter contact gap	mm	6+(1to 0)
Vacuum interrupter contact stroke	mm	-2+(1 to 0)	Measured contact spring compression stroke
Disconnector break gap	mm	≥130
Phase-to-phase center distance	mm	210±1
3-pole closing non-synchronism of vacuum interrupter	ms	≤3
Allowable contact closing bounce time of vacuum interrupter	ms	≤3
Average closing speed of vacuum interrupter	m/s	0.6±0.2
Average opening speed of vacuum interrupter	m/s	0.9±0.2
Conductive loop resistance per pole	μΩ	≤180
Maximum operating torque for manual operation	Nm	≤160
Mechanical life	times	10000

3. Motor Technical Parameters

Rated Voltage		Rated Output Power		Normal Operating Voltage Range
≈220		70W		85%-100% of rated voltage

4. Shunt Trip Unit Parameters

Rated Voltage			Normal Operating Voltage Range
DC 220 DC 110V			80%-120% of rated voltage

For the current-limiting fuse in the load break switch-fuse combination unit, the rated current of the fuse link shall be selected according to the transformer capacity. The reference parameters for selection are as follows: