Motor Suitable Or Not?

I'd like to thank all founders of this forum because it's really very useful.

I have a motor drived by a soft starter and I want to make sure that the motor is suitable for the application. Kindly consider the following specifications for the motor, fan, soft starter.



1- Specifications of the fan are:



Induced fan,

Type: Y5- 48N016.5D

Volume: 85000 m3/ h

Full pressure: 2000 Pa

Fan rotational speed: 960 r.p.m

Motor power: 75 KW

Medium temperature: 270 ºC

Medium <A name=OLE_LINK1>titer: 0.648 Kg/ m3



2- Specifications of the motor are:



Type: 315S-6

Power: 75 KW

Voltage: 380 V

Current: 142.4 A

Frequency: 50 HZ

Efficiency: 92.8

Speed: 990 r.p.m

Insulation class: B

T_st / T_N : 1.6

I_st / I_n : 6.5

T_max / T_n : 2



3- Specifications of the soft starter are:



Power: 132 KW

Current: 250 A





We tried to start the motor by the soft starter many times by different parameters setting but each time the soft starter trips during the starting period and generate alarm (thermal motor model overload), some of the settings used were:





1- Rated current: 142 A,

Starting mode: voltage ramp+ current limit,

Starting voltage: 40%,

Starting time: 30 sec.

Current limit: 400 %

Tripping class: 10



2- Rated current: 142 A,

Starting mode: voltage ramp+ current limit,

Starting voltage: 40%,

Starting time: 25 sec.

Current limit: 450 %

Tripping class: 20



3- Rated current: 142 A,

Starting mode: voltage ramp+ current limit,

Starting voltage: 40%,

Starting time: 30 sec.

Current limit: 500 %

Tripping class: 20



The motor started only after changing the tripping class parameter to trip class 30 and the motor run successfully and drew a current of 80 A. the starting time has also to be parameterized to at least 30 sec. to start the motor.



Now we adjusted the soft starter for the following parameters:

Rated current: 142 A,

Starting mode: voltage ramp+ current limit,

Starting voltage: 40%,

Starting time: 30 sec.

Current limit: 450 %

Tripping class: 30





We are interested in the starting time and tripping class 30, Are these settings suitable for the motor or it is required to replace the motor by another one can withstand this heavy starting load.