CHINT NJBK6 Series Installation instructions

NO:2020.09
Standard: IEC/EN 60947-4-1
NJBK6 Series
Motor Protector
User Instruction

Only professional technicians are allowed for installation and
maintenance.
Installation in any damp, condensed-phase environment with
inflammable and explosive gas is forbidden.
When the product is being installed or maintained, the power
must be switched off.
You are prohibited from touching the conductive part when the
product is operating.
The product shall be stored, installed and used in accordance
with the rated control power supply voltage and specified
conditions indicated in the user instructions.
1
2
3
4
5
Safety Warning

01
Use Purpose
1
Key Technical Parameters
2
NJBK6-36 motor protector (hereinafter referred to as the protector) is
applicable to the protection of overload, loss of phase, three-phase current
unbalance and blocking of none-stop or intermittent duty AC motors with
AC frequency 50Hz, rated insulation voltage below 690V and rated
operating current 1A~36A.
Table 1 Ambient Conditions
Normal use
conditions
Atmospheric
conditions
Installation category
Transport and
storage conditions
Ambient temp.: -5℃~+40℃; average value within 24h
not exceeding +35℃; altitude not exceeding 2000m.
RH shall not exceed 50% when maximum temperature is
+40℃; in case of lower temperature, higher RH is allowed.
Measures should be taken against occasional condensation
due to temperature change.
Ⅲ
-25℃~+55℃
Table 2 Product Specifications and Main Technical Parameters
Model
Setting current (A)
Current setting range (A)
Motor power (kW)
NJBK6-36/3 NJBK6-36/9 NJBK6-36/24 NJBK6-36/36
3
1~3
0.5~1.5
9
3~9
1.5~4.5
24
8~24
4~12
36
12~36
6~18
Plug installation (supported by a contactor of specified model)
Knob
Indicator (green light is on in normal operation;
red light is on in phase loss; red light is on in overload)
Installation method
Setting method
Display method
Protection of overload, loss of phase,
three-phase current unbalance and blocking
1 group of change-over
Protection function
Number of contacts

02
Table 3 Main Circuit Technical Parameters
Product Model NJBK6-36/3 NJBK6-36/9 NJBK6-36/24 NJBK6-36/36
NT00-4 NT00-10 NT00-25 NT00-40
CJX2-32/NC1-32
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Rated insulation
voltage (V)
No.
690
AC220V、AC240V、AC380V，50Hz
85%Us~110%Us
4
3
Type 2
Rated control supply
voltage Us (V),
frequency (Hz)
Allowable fluctuation
range of rated control
power supply voltage
Rated impulse
withstand voltage
Uimp (kV)
Rated conditional
short-circuit current
(kA)
CPD type
SCPD model
Contactor model
CJX2-25/NC1-25
Enclosure protection
class (if applicable)
IP20
M3
0.5
Size of terminal
tightening screw
(or nut)
Torque of terminal
tightening screw (N·m)
Class 3
8h duty or non-stop duty
B
Pollution class
Rated duty
Electromagnetic
environment

03
No.
1
2
3
4
Motion time
No motion within 2h
Motion within 2h
Motion within 2min
2s＜Tp≤10s
Table 4 Auxiliary Circuit Technical Parameters
Product model NJBK6-36/3, NJBK6-36/9,
NJBK6-36/24, NJBK6-36/36
1
2
3
4
5
6
Rated insulation voltage (V)
Rated impulse withstand voltage Uimp (kV)
Agreed free air heating current Ith (A)
Rated operating voltage Ue(V)
No.
380
2.5
5
240V 380V
AC-15
1.5 0.95
Use type under rated operating voltage and
rated operating current Ie(A)
SCPD model 6A Gg
2.1 Motion characteristic
2.1.1 See Table 5 for the motion characteristic of overload protection
Table 5 Motion Characteristic of Overload Protection
Setting current
multiple
1.05
1.2
1.5
7.2
Cold
Thermal
Cold
Starting
condition
Ambient air
temperature (℃)
+20
2.1.2 Motion characteristic of phase loss protection: When any one of the
three-phase currents of the main circuit is open, the protector motions for
3s, with a relative error of ± 20%.
2.1.3 Motion characteristic of three-phase unbalance protection: When the
three-phase current of the main circuit conforms to the following formula,
the protector motions for 3s with a relative error of ± 20%.
30%100%
|| i
3
1i >×
-
=
avg
avg
I
II
Max
Where:

Figure 1 Outline and Installation Size of the Protector
04
Installation
3
3.1 Outline and installation size: see Fig. 1
Unit:mm
Effective current value of each phase.
Mean value of effective three-phase current values.
2.1.4 Motion characteristic of blocking protection: The blocking current set
in the protector is 6Ie. When the current of the main circuit is greater than
the blocking current, the protector motions for 3s with a delay and a relative
error of ± 20%.
2.2 Reset characteristic
i
I
avg
I
After the protector motions, the protector’s reset mode is manual
reset when the rated control power supply voltage is normal; the protector
is immediately reset when the rated control power supply voltage is
disconnected.
54.5max 82max
88max

L3 L2 L1 N
FU1
W1 V1 U1
QS
FU2
W2 V2 U2
W3 V3 U3
W4 V4 U4
QF1
KM
KM
STP ST
QF1
KM
95
96
A1
A2
M
3~
L3 L2 L1 N
FU1
W1 V1 U1
QS
FU2
W2 V2 U2
W3 V3 U3
W4 V4 U4
QF1
KM
KM
STP ST
QF1
KM
95
96
A1
A2
M
3~
Figure 2 Wiring Diagram of the Protector with the
Control Power Supply Voltage of AC220V/AC240V
05
3.2 Wiring diagram: See Fig. 2 ~ Fig. 3.
Figure 3 Wiring Diagram of the Protector with the
Control Power Supply Voltage of AC380V

06
3.3 Test/reset button instructions: “TEST/RST” on the protector is the
test/reset button. Press it when the product is working normally, the
protector motions and the red light flashes; press it after a fault, the
protector is reset.
3.4 Adjustment of the setting current value: the protector uses the setting
knobs with indicating arrows. Based on the setting current value on the
nameplate, set the current according to the rated current and motor load
condition marked on the nameplate of the motor. Adjust the setting current
value of the protector to a scale equal to the rated current value marked on
the motor nameplate.
3.5 Commissioning: After confirming that the wiring and setting are correct,
power on the product and press the start button, then the motor should be
able to run normally and the (green) operation indicator on the panel
should be on. If the red indicator flashes, fine tune the setting value until
the red indicator light just does not flash.
Notes:
1 Check the performance of the protector on a regular basis. Perform overload
and loss of phase testing. The testing should be performed by professional
technicians to ensure the safety of electricity use.
2）The setting error of the protector shall not be greater than 5%. When the
current of the main circuit is within this range, the overload indicator may be on.
3）If the motor stops during its operation, the motor should be checked for loss
of phase or overload. First, check whether the temperature rise of the motor is
too high. If the temperature rise is too high, the stop may be caused by
overload; if not, the motion of the protector may be caused by the loss of phase
of the circuit. Check whether the three-phase power supply is normal, whether
the dynamic and static contacts of the AC contactor are in good contact, and
whether the three-phase power line of the motor has loosened; if everything
goes well but the motor still cannot be started, then carefully check whether the
self-locking contact of the AC contactor and the terminal wiring of the protector
have loosened. The motor cannot be started until the fault is eliminated. When
the fault is not eliminated, it cannot be started forcibly for fear of accidents.
4）Do not open the protector without permission, so as to avoid danger or
affecting the normal operation of the protector.
）

07
Maintenance
4
Table 6 Analysis and Troubleshooting of Common Faults
Symptoms Cause analysis Troubleshooting method
Whether the wire and the
terminal are in reliable
contact, and whether the
power terminal is correctly
wired.
The power indicator
light is off.
The motor stops in
operation
Environmental Protection
5
In order to protect the environment, the product or product parts
should be disposed of according to the industrial waste treatment process,
or be sent to the recycling station for assortment, dismantling and recycling
according to local regulations.
4.1 The terminal of the protector should be tightened on a regular basis.
4.2 Avoid squeezing the product; the product should be stored in a well-
ventilated place.
Connect wires reliably
according to the user
instructions.
Whether the motor has
phase loss or overload.
Trouble shooting according
to Note 3) under No. 3.5.

QC PASS
Test date: Please see the packing
ZHEJIANG CHINT ELECTRICS CO.,LTD.
NJBK6 Series
Motor Protector
IEC/EN 60947-4-1
JDQ Check 10
09

NJBK6 Series
Motor Protector
User Instruction
Zhejiang Chint Electrics Co., Ltd.
Add: No.1, CHINT Road, CHINT Industrial Zone,North Baixiang,
Yueqing, Zhejiang 325603,P.R.China
E-mail: [e-mail]
Website: http://en.chint.com