CHINT NA1, Manual

Rated current range [Ii]

Error

Line current [I]

Operating Characteristics

≤

0.85Ii

＞

1.15Ii

no-action

action

(2~15)In
+OFF(Power off)

±15%

4

6

8

10

2

3

Ii

12

15

Off

(A~J)In
+OFF(Power off)

±10%

＜

0.9Ig

＞

1.1Ig

2

I T OFF

2

I T  ON

I

＞

J

2

I T ON

I

≤

J

±15%

7.6.4 Single-phase earthing fault protection

7.6.3 Short-circuit instantaneous overcurrent protection 

Rated current range [Ig]

Error

Line current [I]

no-action

time

-

delay

action

0.1     0.2     0.3     0.4

0.1     0.2     0.3     0.4

2

2

anti-time-limit delay I Tg

=(

J

)

tg

Operating time [tg(s)]

Time (delay) error

Meaning of  Ig

Rated

current

In

In

≤

400A

400A<In≤1200A

1200A<In

A

0.3

0.2

500A

B

0.3

0.3

640A

C

0.4

0.4

720A

D

0.5

0.5

800A

E

0.6

0.6

880A

F

0.7

0.7

960A

G

0.8

0.8

1040A

H

0.9

0.9

1120A

J

1.0

1.0

1200A

Note

×In

×In

×

I n

.4

.4

. 3

. 2

.1

.1

. 2

. 3

X

2

I t

Tg

(

s

)

Ig

E

F

G

H

J

A

B

C

D

Off

ON

Example 3: If it is known that the single-phase earthing
protection setting current for the intelligent controller with
rated current of In=800A is as the setting position of C, the
tripping time is set as the inverse time limit 0.4s.
Now there is a failure in the circuit, the circuit current I=400A, 
then the actual tripping time can be worked out; it can be seen 
from the table that the result is 
C=0.4
Ig=C×In=0.4×800=320A 
So I=400A

＞

1.1Ig 

2

2

According to the formula I T =(J) t  

g

g

2

2

(400) ×T =(1.0×800) ×0.4 

g

T =1.6s 

g

Note: For the intelligent controller, the current settings for the 
long time-delay and the short-circuit short time-delay and the 
intantaueous overcurrent protection should not come across
each other, and the condition of I

＜Isd＜

Ii must be ensured. 

R

Rated control supply voltage Us(V)

Operating voltage (V)

Power dissipation (W)

Closing time

AC230 AC400

(0.7~1.1)Us

200VA

50±10ms

AC230 AC400

(0.85~1.1)Us

200VA

50±10ms

DC220 DC110

200W

DC220 DC110

200W

8.2 Shunt release
      After the shunt release is energized, the breaker is switched off 
      instantaneously to allow remote operation.
 

8.3 Closing electromagnet

After the motor-driven energy storage is ended, energizing the 
closing electromagnet will make the energy storage spring force of 
the operating mechanism to be released instantaneously to rapidly 
switch the breaker on.

Rated operational voltage Ue(V)

Operating voltage(V)

Reliable switching voltage(V)

Reliable not-switching voltage(V)

Power dissipation(W)

AC230 AC400

(0.35~0.7)Ue

(0.85~1.1)Ue

≤

0.35Ue

20VA

Rated control supply voltage Us(V)

Operating voltage (V)

Power consumption (W)

Breaking time

Under-voltage release
(Inm=1600A)

Under-voltage release
(Inm=3200A, 6300A)

Shunt release
(Inm=1600A)

Shunt release
(Inm=3200A, 6300A)

Closing electromagnet
(Inm=1600A)

Closing electromagne
(Inm=3200A, 6300A)

8. Accessories 

Operating characteristic:

Operating characteristic:

NA8G

Air Circuit Breaker

P-034

P-033

NA8G

Air Circuit Breaker

     Explanation for parameter setting

     Current of short-circuit instantaneous over current protection: 

Ii=[2-3-4-6-8-10-12-15-OFF]×In, optional.
The method for setting the current of short-circuit 
instantaneous

      overcurrent protection is similar to that for long time-delay

overcurrent protection setting. As shown in the figure, the 
instantaneous overcurrent  protection current setting value is 
8In. 

      Explanation for parameter setting

      Current of  single-phase earthing protection : Ig=(A-B-C-D-E-

F-G-H-J)×In, optional. 

      There are nine setting positions for the protective delay 

tripping time, wherein 4 settings represent the definite-time 

2

limit characteristic (i.e., I t OFF), 4 settings the inverse-time 

2

limit characteristic (I t ON), and 1 setting the function of 
closing the single-phase earthing protection (X).

      When the tripping time is set as definite-time limit operating 

characteristic (i.e., the arrow points at the OFF area), the 
tripping time can be selected as tg=0.1s-0.2s—0.3s-0.4s-x 
(i.e., the function of closing the single-phase earthing 
protection).

      When the tripping time is set as inverse-time limit operating 

2

characteristic (i.e., I t ON), there are two cases: 

①

 in the case of I

＞

1.1Ig and I

＞

J, the result of the automatic 

changeover process is the definite-time limit operating 
characteristic, tg=0.1s-0.2s-0.3s-0.4s; 

②

 The case of the current meeting the condition of 1.1Ig

＜

I

≤

J 

represents the inverse-time limit characteristic and the actual 
tripping time is calculated according to the formula 

2

2

I Tg=(J) tg.
In the formula, I is the circuit current, Tg is the actual 
operating time, J is the setting current, and tg is the setting 
tripping time.The method for setting the parameter is similar 
to that for long time-delay current protection. As shown in 
the figure, the   single-phase earthing protection current is 
C×In

，

and the tripping time setting is tg=0.4s in the setting 

2

position of inverse time limit (I t ON).

7.7 

Explanation

for

auxiliary

functions

a

. 

Explanation

for

test

functions

When

onsite

adjustment

, 

periodical

inspection

or

overhaul

is

made

with

the

controller

supported

by

the

breaker

, 

breaking

several

times

is

necessary

by

using

the

test

functions

of

the

controller

to

check

the

cooperation

of

the

controller

and

the

breaker

. 

With

the

breaker

on

, 

press

the

test

key

, 

and

the

intelligent

controller

will

trip

instantaneously

to

cut

off

the

breaker

.

     Note

: ① 

This

function

can

be

used

only

when

onsite

adjustment

or

overhaul

for

the

breaker

is

made

, 

and

shall

not

be

used

during

the

normal

operation

.

② 

Each

time

before

the

controller

is

switched

on

, 

it

is

necessary

to

press

the

reset

button

in

the

upper

position

of

the

controller

panel

so

that

the

breaker

can

be

switched

on

again

for

operation

.

b

. 

Explanation

for

fault

memory

    The

controller

still

has

the

function

of

fault

memory

after

reset

or

de

-

energized

to

keep

a

latest

historical

event

for

post

analysis

. 

Only

when

there

is

a

new

fault

again

, 

the

original

information

is

cleared

with

the

current

latest

faulty

data

saved

. 

For

the

inquiry

method

, 

refer

to

the

above

explanation

about

fault

display.

7.8 Explanation for display function

When the rated current is greater than or equal to 400A, the 
primary current shall not be lower than 0.4In for single phase

，

and 0.2In for three phases for normal operation of the 
breaker. 

      When the rated current is less than 400A, the primary current 

shall not be lower than 0.8In for single phase

，

and 0.4In for 

three phases for normal operation of the breaker. 

      Note: When the AC220V ST power module is energized, and 

the voltage falls to AC120V, there will be no display on the 
controller. 

      When the AC380V ST power module is energized, and the 

voltage falls to AC200V, there will be no display on the 
controller. 

      a. Current display Error range for current display: ±5% 

b. Voltage display Error range for voltage display: ±1.5% 

8.1 Under voltage release

When the under voltage release is not energized, neither 
power-driven nor manual operation can make the breaker on. 
For the under voltage release, there are two varieties: 
instantaneous and time-delay operations.The time for the 
under voltage time-delay release is Inm=1600A, the time can 
be selected from but not adjusted in the range of 0 – 7s;

Inm=3200A or 6300A, the time can be selected from but not 
adjusted among 0.5s, 1s, 3s, and 5s.  When, within 1/2 delay 
time, the power voltage returns to 85%Ue or above, the 
breaker will not get disconnected.

Operating characteristic: