MetalKain

Yes, I tried with 20 seconds but the result was the same: the motor starts and the current is limited to 280 A, the motor sounds like it is about to reach the nominal speed but the same fault appears.

I really don't know what to do? I don't know if the starter can't handle the motor (motor 62A, starter 80A) or the motor can't handle the load ...

I really don't know what to do?

PISCEAN 2010

Hello,
You have not specified the complete MLFB number of 3RW40 softstarter. But from the description I presumed as it is normal starting. Actually your application demand is heavy duty starting, so you should have selected 3RW4047 series soft starter. Please find attached here with sheet which explaines the technical difference between normal & heavy starting. (Extracted from the manual of SIRUS softstarter.

RBM

MetalKain

Yes, I tried with 20 seconds but the result was the same: the motor starts and the current is limited to 280 A, the motor sounds like it is about to reach the nominal speed but the same fault appear ...

Hi,

You would have already tried this, but just checking to make sure these points are not missed.

starting method: By default, its in V.Ramp+Curr.Limit. Did u tried changing into just Volt.Ramp or just Torque Control?? (not ideal solution. need to know if it works)

Hi,

I think what you say is only possible in the 3RW4044 series.

Please can you tell me how you had solved that problem.

I am facing typical problem with same soft starter and same fan.

Your help will be really appreciated.

Regards,

Tariq

Hi Tariq,

We realize that the current calculation for that kind of fan was wrong. In fact I had to use another soft starter with higher current capacity. I used a 3RW4434 (100A), don´t forget to configure it for heavy work.

Best regards,

Dear Sir,

Thanks for your response. how did you came to know that your application requires heavy duty starting? 

We have 26 such fans. Attached is the picture of fan and motor name plate. They are 30kW motors and we are using 3RW4038-1BB14 but getting thermal overload alarm in soft starter. I tried all settings which were mentioned in previous posts but failed...

The starting current is reaching around 200A (setting 4 x Ie) & its reaching 250A (setting 5 x Ie).

Before we were using 3RW3038-1BB14 which does not have current limiting setting and the starting current was going around 370A. (& it was tripping the Motor circuit breaker 3RV1).

We are in big problem regarding selection of soft starter.

Thanks

Tariq

Tariq

Dear Sir,

We have 26 such fans. Attached is the picture of fan and motor name plate. They are 30kW motors and we are using 3RW4038-1BB14 but getting thermal overload alarm in soft starter. I tried all settings which were mentioned in previous posts but failed...

We are in big problem regarding selection of soft starter.

Thanks

Tariq 

Hello,

Please try by setting parameters as below.

U= 30%

t = 30 sec

xIe = 4Ie

Class = 20 set trip class

With this setting, soft starter  should work.

Tariq

Dear Sir,

Thanks for your response. how did you came to know that your application requires heavy duty starting? 

We have 26 such fans. Attached is the picture of fan and motor name plate. They are 30kW motors and we are using 3RW4038-1BB14 but getting thermal overload alarm in soft starter. I tried all settings which were mentioned in previous posts but failed...

The starting current is reaching around 200A (setting 4 x Ie) & its reaching 250A (setting 5 x Ie).

Before we were using 3RW3038-1BB14 which does not have current limiting setting and the starting current was going around 370A. (& it was tripping the Motor circuit breaker 3RV1).

We are in big problem regarding selection of soft starter.

Thanks

Tariq

 

Hello Tariq,

I'm attaching a part of the Soft Starter Manual where it explains what applications are considered "very heavy start" and explains the power class that your starter must have for your motor.

In my experience I could recomend you to use a 3RW4426 or 3RW4427, but if you try on your 3RW4038 with Ie=72A (max) and Class=OFF it is possible that your fan start.

These kind of large fans are very difficult to use with soft starters, some people say that VFD is better for that but ... I'm not an expert to say if that is true or not. Good luck and let me know if you solve your issue.

Best regards,

New question published by KenGrundfos is split to a separate thread with the subject 3RW406-1AB14 - Why seeing high current spike on only phase B?.

Best regards
Jen_Moderator