ZN28-12 Indoor Vacuum Circuit Breaker

Selection

Operating conditions

1. The environment temperature: upper limit +40℃, lower limit -15℃; 2. Altitude: ≤2000m; 3. Relative humidity: daily average value is not greater than 95%, monthly average is not greater than 90%; 4. Earthquake intensity: less than 8 degrees; 5. No fire, explosion, pollution, chemical corrosion and severe vibration place.

Technical data

Item	Unit	Parameter
Parameters of voltage, current, life
Rated voltage	kV	12
Rated short time power frequency withstand voltage (1min)	kV	42
Rated lightning impulse withstand voltage (peak)	kV	75
Rated frequency	Hz	50
Rated current	A	630 1250	630 1250	1250 1600 2000 2500	1600 2000 2500 3150
Rated short-circuit breaking current	kA	20	25	31.5	40
Rated short-time withstand current (RMS)	kA	20	25	31.5	40
Rated peak withstand current	kA	50	63	80	100
Rated short-circuit closing current	kA	50	63	80	100
Rated single / back-to-back capacitor bank breaking current	A	630/400
Rated short-circuit current duration	S	4
Rated short-circuit current breaking times	Times	50		30
Rated operating sequence		O-t-CO-180s-CO rated short-circuit breaking current less than 31.5kA, t=0.3s rated short-circuit breaking current 40kA, t=180s
Rated operation voltage		≌ 220/110
Mechanical life	Times	≥10000
Mechanical property parameters
Open clearance between contacts	mm	11±1
Overtravel	mm	4±1
Contact closing bounce time	ms	≤2		≤3
Three-phase, switching synchronism	ms	≤2
Average opening speed	m/s	0.9~1.3
Average closing speed	m/s	0.4~0.8
Opening time (rated voltage)	ms	≤60
Closing time (rated voltage)	ms	≤100

Overall and mounting dimensions(mm)

Type				H	H1	H2	H3	A	A1	A2	B	B1	B2	B3
ZN28-12/T	2500 3150	-40		780	700	268	371	581	450	390	700	560	275	690
ZN28-12/T2000-31.5				697	677	235	347	550	380	330	634	480	250	620
ZN28-12/T	630 1250	-	20 31.5	697	677	235	347	550	380	330	594	440	230	580

Rated current	20KA, 25KA, 31.5KA		40kA
Code	A	B	A	B
Data	250	610	275	690