- MS 1-32 type Motor Protection Circuit Breaker (MPCB) is applicable to AC electric circuit with frequency 50/60 Hz, rated voltage up to 690 V and rated current up to 32A. It protects against the overload, disconnection of phase and short-circuit of three-phase asynchronous motors, and it is suitable for unfrequently starting & breaking operations for the motor. It can also be used for electrical circuit protection, unfrequent load changeover and isolation. It provides the function of current rating adjustment to suit the motor.
Meaning and classification models
Normal operation and mounting requirement
- Altitude above sea level on more than 2000 m.
- Ambient temperature -5°C~ +40°C, average temperature not exceeding 35°C.
- Humidity not exceeding 50% at 40°C .Allowing higher humidity at lower temperature, e.g. the humidity should not exceeding 90% at 20°C. Special treatment should be taken for occasional coagulate dew due to temperature alteration.
- Ambient Pollution class 3.
- Installation sort: III.
- Product shall be installed vertically, titling angle no more than ±5°, at the place where there shall be no severe impact or vibration.
- Tripping level：10A
- Rated operation mode: uninterrupted operating.
1, Rated Isolating Voltege Ui：690 V；
2, Rated Operating voltage Ue：230/240V、400/415V、440V/460V、500V/525V、600V/690V；
3, Rated Frequency：50/60Hz
4, Frame Rating Inm：32A
5, Rated Impacting Voltage Uimp：6 KV；
6, Frame Rating Inm, Rated Frequency, Rated Current Ie, Rated Current Adjusting Range, and Rated Operating Voltage Ue are figured in Table 1.
7, Short-circuit Capacity: Under the circumstances of rated current 32A and rated voltage 400V, the rated limit short-circuit current is Icu =13.3KA, and rated operating short-circuit current is Ics=10KA
Table 1 Basic Parameter
|Frame Rating Inm (A)||Rated Frequency (Hz)||Rated Current Ie (A)||Rated Current Adjusting Range (A)||Rated Operating Voltage Ue|
8. The Rated Power of three-phase motor controlled by the product (MPCB) is figured in Table 2
Table 2 Rated Power of Three-phase motor controlled by the product (MPCB)
|Frame Rating Inm (A)||Rated Frequency
|Rated Current Ie (A)||Rated Current Adjusting Range
|Rated Power of Three-phase
9. Protection Class: IP 20
10.Operation Performance: Table 3
Table 3 Motor Starter operation characteristics
|Rated Current A||Operation cycles per
|Without current||With current||Total|
11. Overload tripping characteristics: Table 4
Table 4 Overload tripping characteristics
|Step||Multiple of setting current||Start State||Engaged time||Expecting result||Ambient temperature|
|1||1.05 Ie||Cold||t≥2h||No trip||+20°C±2°C|
|2||1.2 Ie||Heat (operating immediately after step 1)||t＜2h||Trip||+20°C±2°C|
|3||1.5 Ie||After heat stabilization at one time of setting
12. Tripping characteristics for unbalanced load in phases (disconnection of phases): Table 5
Table 5 Tripping characteristics for unbalanced load in phases (disconnection of phases):
|Step||Multiple of setting current||Start State||Required time||Engaged result||Ambient temperature|
|Random two phases||The third phase|
|1||1.0 Ie||0.9 Ie||Cold||≥2h||No trip||+20°C±2°C|
|2||1.15 Ie||0||Heat (operating immediately to reach the required
current after step 1)
13. Temperature compensation characteristics: Table 6
Table 6 Temperature compensation characteristics
|Step||Multiple of setting current||Motoring circumstance||Required time||Except result||Environment temperature|
|1||1.0 Ie||Cold||≥2h||Do not trip||+55°C±2°C|
|2||1.2 Ie||Heat (operating immediately to reach the required
current after step 1)
|3||1.05 Ie||Cold||≥2h||Do not trip||-5°C±2°C|
|4||1.3 Ie||Heat (operating immediately to reach the required
current after step 3)
14. Setting value of the instantaneous tripping value and tripping characteristics: Table 7
Table 7 Instantaneous trip curve and tripping current
|Instantaneous tripping curve||Level||Tripping current value Ir||Tripping time Tp, s|
Able to trip at setting current (13 In) within tolerance ±10%.
15. Selection of complementary fuse When the expected short-circuit current at the installation place exceeds the MPCB’s rated limit short-circuit capacity, a complementary fuse shall be needed. The selection is according to Table 8
Table 8 Current ratings of the needed complementary fuse gG/gL while Icc＞Icu (A)
|Rated current Ie (A)||1||4||6||8||10||13||17||22||26||32|
|Voltage level||current ratings of the needed
complementary fuse gG/gL while Icc＞Icu (A)
Remark: ★ means no fuse needed.Overall and Mounting Dimensioned Chart