Changeover Switch

NH40SZ
2. Type designation
N H 40 - □ / □ SZ □ □

Y:Liquid crystal display

Normal type
Main power supply —— standby power
supply, automatic change and automatic
recovery;
Ⅰ: Mains supply-mains supply, mutual
standby, phase loss protection;overvoltage
and undervoltage protection;
Ⅱ: Mains supply-mains supply, automatic
change and automatic recovery, phase
loss protection, overvoltage and
undervoltage protection;
Ⅲ: Mains supply-oil engine, automatic
change and automatic recovery, phase
loss protection, overvoltage and
undervoltage protection;

Dual-power supply automatic transfer

NH40SZ
Automatic Changeover Switch “3” represents three poles
1. General “4” represents four poles
NH40SZ automatic changeover switch disconnector
integrates electrical and mechanical interlocking systems
Rated operational current
to guarantee safe transfer operation.
It is applicable for the three-phase four-wire power supply
system of AC 50Hz, rated voltage AC 380V ,rated current up Design sequence No.
to 3150A.
It can realize automatic and manual changeover between
normal and back up power supply power, Isolating switch
and stop power supplying to load when changeover
process of power supply is carried out. Company code
The switch is applicable for two circuits power supply
and in the condition which requires
high quality power supply.
Standard: IEC 60947-6-1

3. Technical data

Conventional
16 32 40 63 80 100 125 160 200 250 315 400 630 800 1000 1250 1600 2000 2500 3150
thermal current (A)
Ie (A) 16 32 40 63 80 100 125 160 200 250 315 400 630 800 1000 1250 1600 2000 2500 3150
Ui (V) 660 800
Uimp (V) 8 12
Ue, Us Ue=400V; Us=220V
Rated making and breaking capacity 6Ie
Icw (KA) 5 10 12.6 50 50
Converting time (S) ≤3s ≤4s

Rated controlling Startup 300 325 355 400 600

capacity (W) Natural 55 62 74 98 120

Operation force (N) 30~50 40~60 65~100 75~120 200~300 250~400

Empower the World >> 46

 Changeover Switch
NH40SZ
4. Control characteristics and product structure Control characteristics of type II switch:
a. This switch applies to the automatic change and automatic
4.1 Control characteristics:
recovery of mains supply-mains supply systems. Power supply I
There are two types of switch products, three-pole and four-pole
precedes. When power supply I is normal, it is switched on;
(three poles + switchable neutral pole).
when power supply I fails and power supply II is normal, the
Four control types (common type, I, II, III),usually it is common
switch changes to power supply II; when power supply I resumes,
type.
the switch automatically changes to power supply I. The main
Control characteristics of common type switch: power supply changes to the standby power supply (the delay
a. This switch applies to the automatic change and automatic continuously adjustable between 1～999s), the standby power
recovery of main power supply-standby power supply (including supply changes to the main power supply (the delay continuously
manual oil generator; Note: Manual oil generator does not have adjustable between 1～999s).
to be used with type III switches) systems. Power supply I precedes. b. Three-phase overvoltage, undervoltage and phase loss detection
When power supply I is normal, it is switched on; protection functions.
when power supply I fails and power supply II is normal,
the switch changes to power supply II; when power supply I Control characteristics of type III switch:
resumes, the switch automatically changes to power supply I. a. This switch applies to the mutual standby or automatic change
and automatic recovery of mains supply-oil generator (automatic
Control characteristics of type I switch: oil generator with signals) systems. Power supply I (the mains
a. This switch applies to the mutual standby of mains supply-mains supply) precedes. When power supply I fails, the switch gives a
supply systems. When the switch is in the “0” position, power signal to start the oil generator. The oil generator has warm-up
supply I precedes. When power supply I fails and power supply II delay (continuously adjustable between 0～180s) function.
is normal, the switch changes to power supply II; when power After the oil generator has started, the switch changes to power
supply II is on and power supply I resumes, the switch does not supply II (the oil generator). When power supply I resumes, the
automatically change to power supply I, it will change to power switch automatically changes to power supply I, the oil generator
supply I only when power supply II fails. The main power supply automatically stops after a cooling delay (continuously adjustable
changes to the standby power supply (the delay continuously between 0～180s).
adjustable between 1～999s), the standby power supply changes b. Three-phase overvoltage and undervoltage protection functions
to the main power supply (the delay continuously adjustble for mains supply and oil generator.
between 1～999s).
b. Phase loss detection protection function, overvoltage、 Type I, type II and type III switches have:
undervoltage protection fuctions. 1) Automatic, remote and manual control functions
4.2 Product structure 2) A 0.5s delay of the detection signal, to prevent misoperation.
3) A remote control “0” position in automatic state.
4) A key switch for the selection of operation mode.

16A-100A/4(Common type)

Model and specification

Control voltage

Position indication

Electrical key lock

Mechanical padlock
Switch body

Line II connected to the standby power supply

Line I connected to the standby power supply

302~305 switch
state indicating
terminals

Operating handle

47 >> Empower the World

Changeover Switch
NH40SZ
100A/3 common type; 100A/3, 4 typeⅠ, type II, type III; 125A-3200A/3, 4 common type, type I, type II, type III

Model and specification

Control voltage
Position indication
Electrical key lock

Mechanical padlock

Switch body

Line I connected to the standby power supply

Line II connected to the standby power supply
101~106 control power supply input and output terminals
201~206 switch control terminals
301~306 switch operating state indicating terminals

401~406 switch operating state indicating terminals (reserved) (only for 315A and above)

501~506 electrical key lock, mechanical padlock state indicating terminals (only for 315A and above)

Operating handle

a. Electrical key lock: It controls the power supply of the internal c. Mechanical padlock: Before maintenance, put the switch to the
control circuit of the switch. When the electrical lock is in the 0 position with the operating handle, pull up the padlock structure
“Automatic” position, the switch can be operated automatically and lock the padlock. (Pulling up the mechanical padlock switches
or remotely. When the electrical lock is in the “Manual” position, off the internal control power supply of the switch so that it
the switch can only be operated manually; cannot be operated electrically or manually);
b. Operating handle: When operating the switch with the operating d. Position indication: It indicates the operating position (I; 0; II)
handle, the elctrical lock must be in the “Manual” position; of the switch;
e. Control voltage: The control voltage class of the switch is 220VAC;
f. Switch body: The front part is line I, which is connected to the
“Normal power supply”; the rear part is line II, which is connected
to the “Standby power supply”.

4.3 Connection terminal of control circuit

Common type

Remote & Automatic Remote control at Automatic control at

control option breaking status making status
SUPPLY VOLTAGE
Connection Normal powerⅠ Backup powerⅡ Connection
terminal 1 220VAC OV 220VAC OV terminal 2
101 102 103 104 105 106 201 202 203 204 205 206

POSITION POSITION
Connection Connection
terminal 3 terminal 3
301 302 303 304 305 306 302 303 304 305
(16A~100A common type only)

MANU-PADLOCK

PREBREAK
Connection Connection
terminal 4 terminal 5 501 502 503 504 505 506
Manual operation at breaking status With padlock
401 402 403 404 405 406 Automatic operation at breaking status
at making status Without padlock
at making state

Empower the World >> 48

 Changeover Switch
NH40SZ
Type I and type II

Remote & Automatic Remote control at Automatic control at

Communication control option making status breaking status

Connection Connection Control

terminal 1 terminal 2

101 102 103 104 105 106 201 202 203 204 205 206

I II type 3P only
PREBREAK
Connection Connection
terminal 3 terminal 4

301 302 303 304 305 306 401 402 403 404 405 406

Connection
terminal 5 501 502 503 504 505 506
Manual operation at breaking status With padlock at
Automatic operation breaking status
at making status Without padlock at
making state

Type III

Remote & Automatic Remote control at Automatic control at

Generator starting Communication control option making status breaking status
Control/Auto Selection
Connection Connection
terminal 1 terminal 2

101 102 103 104 105 106 201 202 203 204 205 206

III type 3P only Predict

Connection Connection
terminal 3 terminal 4

301 302 303 304 305 306 401 402 403 404 405 406

Connection
terminal 5 501 502 503 504 505 306
Manual operation at breaking status With padlock
Automatic operation at breaking status
at making status Without padlock
at making state

Terminal 1, main options 305-Type I, II, switch I controls zero-line “N1”;

101, 106-Note: They do not connect with other terminal (only type III switch I controls zero-line “N” (only for 3 poles)
for common type) Terminal 4, pre-breaking auxiliary contact
102, 103-Power control terminal of circuit Ⅰ(only for common type) 306-Type I, II, switch II controls zero-line “N2”; type III,
104, 105-Power control terminal of circuit Ⅱ(only for common type) switch II controls zero-line “N(G)”
101, 102-Generator starting signal input (for type III) 402, 403, Pre-breaking position of indication switchⅠ.
103, 104-Firefighting +24V input, enforce "0", both switches breaks 404, 405, Pre-breaking position of indication switchⅡ.
(for type I, II, III) Terminal 5 Manual and automatic operation mode
105, 106-Communication Interface (Reserved) and whether locking the switch
502, 503, Automatic and manual control indication
Terminal 2, remote control 504, 505, Indcation of whether locking
201, 206-Terminal of remote controlling, automatic controlling the switch Terminal 6 Start-up terminals
functions. Remote control at breaking status and automatic for diesel generator
control at making status.
202, 203-Making switch I. 501,506: They are supuerfluity.
202, 204-At “0” position, both switches breaks (for type I, II, III)
(include preferring position “0”)
202, 205-Making switch II.
Terminal 3, position indication and zero-line terminal
301, 302-Switch I position
301, 303-At “0” position, all swithes breaks
301, 304-Switch II position.

49 >> Empower the World

Changeover Switch
NH40SZ
5. Connection diagram
5.1 16A~100A 4 poles main switch wiring diagram

Normal power supply Standby power supply

Secondary connection diagram
A phase B phase C phase N phase Normal Standby
power supply power supply

Load output terminal

(Special attention should be paid to the sequence of connection.)

Connected to load output terminal

HL1 and HL2 are respectively the resumption indicators of the

normal and standby power supplies;
HD1 and HD2 are respectively the service indicators of the normal
and standby power supplies;
302~305 are switch terminals.

5.2 125A~3150A main switch wiring diagram

Normal power supply Normal power supply

Connected to load output terminal

125A~3150A

Note: Secondary connection of terminal 1 is required

Load output terminal (for 16A~100A with forced reset, the connection mode
is the same as above).

5.3 125A~3150A Secondary wiring diagram (3P, 4P)

Normal Standby
power supply power supply

Connected to load output terminal

125A~3150A
HL1 and HL2 are respectively the resumption indicators of the
normal and standby power supplies;
HD1 and HD2 are respectively the service indicators of the normal
and standby power supplies;
FU1 and FU2 are 5A fuses;
101~106, 201~206, 301~306 are switch terminals.

Empower the World >> 50

 Changeover Switch
NH40SZ
5.4 Depending on the operating mode, the following connection modes can be used for terminal 2:
a. Fully automatic connection mode

201 202 203 204 205 206

201 and 206 short connected (Normal Type)

Note: Secondary connection of terminal 1 is required.

b. Remote reset (the two power supplies are disconnected)

connection mode

201 202 203 204 205 206

Forced reset contact (passive)

c. Remote connection mode (Note: SB1 and SB2 are

external push-button switches)

201 202 203 204 205 206

d. Fully automatic + manual (remote) connection mode

(Note: SB1 and SB2 are external push-button switches)
Automatic

Remote
Manual

201 Automatic

202 Remote

203

204

205

206

Normal Mode
Note: When switch SA is in the automatic position,① and ②
are connected.
When switch SA is in the manual position, ④ and ③
are connected, but the switch SA must break.

51 >> Empower the World

Changeover Switch
NH40SZ

5.5 Connection diagram

NH40-16~100
16~100A 3P connection chart

A
B
C

C
B
A

A B C

16~100A 3P connection chart

16~100A 4P connection chart

A
B
C
N
N
C
B
A

A B C N

16~100A 4P connection chart

Correct mounting of the switch:

a. Copper busbars I and II are respectively connected to phases
R, S, T, N of the normal (front) and standby (rear) power supplies
from left to right.

b. The control power supplies are obtained respectively from

phases T and N of the normal and standby power supplies.

c. AC220V control power supplies I and II are respectively

connected to terminals 102~103 and 104~105, among which
102 and 104 are respectively the live wires of the normal and
standby power supplies.

d. Terminals 1.1 and 106 are only used as the control power
supplies of the signal lamps. Note: They should not be connected
to any other lines.

e. When upper (lower) incoming line is used, phases R, S, T, N of

the lower (upper) lines I and II are respectively connected with
copper busbars or conductors as the output.

Empower the World >> 52

 Changeover Switch
NH40SZ
6. Mounting dimension of NH40SZ automatic changeover switch disconnector
16～ 1600A

Electric ware controlling connecting area J

r
ete
N
Maxim rotation scope of handle

am
E R

du
φX

nu

L
Se
G
B1

B
K

35
20
18

16
35 40
Y V P P P 60 80
Y1
A1
C 1000A
A 1250A 1600A

2000～3150A

J 142
2000

φX N
L

50
40
220

250
K
B
400

25
20

40 50

80 120
P Y R 120 120 120
V
Y1 A1 2000A 2500A 3150A
C A

53 >> Empower the World

Changeover Switch
NH40SZ

Specification NH40SZ Mounting dimensions

Ith/Poles A A1 B C E J K L N P R V φX Y Y1
16A/3, 4 280 245 106 170 133 234 84 7 75 30 14 20 6 43 93
32A/3, 4 280 245 106 170 133 234 84 7 75 30 14 20 6 43 93
40A/3, 4 280 245 106 170 133 234 84 7 75 30 14 20 6 43 93
63A/3, 4 280 245 106 170 133 234 84 7 75 30 14 20 6 43 93
80A/3, 4 280 245 106 170 133 234 84 7 75 30 14 20 6 43 93
100A/3, 4 280 245 106 170 133 234 84 7 75 30 14 20 6 43 93
125A/3 450 290 135 240 208 275 95/110 7 87 36 20 45 9 58 135
160A/3 450 290 135 240 208 275 95/110 7 87 36 20 45 9 58 135
125A/4 480 320 135 240 208 302 95/110 7 87 36 20 45 9 58 135
160A/4 480 320 135 240 208 302 95/110 7 87 36 20 45 9 58 135
200A/3 460 330 170 240 208 312 95/110 7 87 50 25 45 11 60 140
250A/3 460 330 170 240 208 312 95/110 7 87 50 25 45 11 60 140
200A/4 510 380 170 240 208 358 95/110 7 87 50 25 45 11 60 140
250A/4 510 380 170 240 208 358 95/110 7 87 50 25 45 11 60 140
315A/3 465 375 240 315 270 355 180 11 95 65 32 37.5 11 84 195
400A/3 465 375 240 315 270 355 180 11 95 65 32 37.5 11 84 195
630A/3 465 375 260 315 270 355 180 11 95 65 40 37.5 13 84 195
315A/4 525 435 240 315 270 415 180 11 95 65 32 37.5 11 84 195
400A/4 525 435 240 315 270 415 180 11 95 65 32 37.5 11 84 195
630A/4 525 435 260 315 270 415 180 11 95 65 40 37.5 13 84 195
800A/3 900 530 310 368 320 500 220 11 85 120 60 198 13 108 252
1000A/3 887 515 310 368 320 490 220 13 88 120 60 198 13 108 252
1250A/3 887 515 360 368 320 490 220 13 88 120 70 198 13 108 252
1600A/3 887 515 360 368 320 490 220 13 88 120 80 198 13 108 252
800A/4 1010 640 310 368 320 610 220 11 85 120 60 198 13 108 252
1000A/4 1007 635 310 368 320 610 220 13 88 120 60 198 13 108 252
1250A/4 1007 635 360 368 320 610 220 13 88 120 70 198 13 108 252
1600A/4 1007 635 360 368 320 610 220 13 88 120 80 198 13 108 252
2000A/4 1007 633 455 562 495 467 220 11 85 147 80 33 13 226 457
2500A/4 1007 633 455 562 495 467 220 11 85 152 120 33 13 230 462
3200A/4 1007 633 505 562 495 467 220 11 85 152 120 33 13 230 462
2000A/3 892 518 455 562 495 359 220 11 85 152 120 33 13 230 462
2500A/3 892 518 455 562 495 359 220 11 85 152 120 33 13 230 462
3150A/3 892 518 505 562 495 359 220 11 85 152 120 33 13 230 462

Empower the World >> 54