Previous in Forum: Pump Operation   Next in Forum: Thyristor for Voltage Regulator
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
4 comments
Rate Comments: Nested
expertsuresh
Participant

Join Date: Jun 2012
Posts: 3

MPCB for Drive Output Selection

07/28/2012 8:51 AM

Dear All

I am using Sinamics G 120 of siemens make drive for my multi motor application. The drive rating is 4 KW and I am controlling .25 Kw motor of 10 nos. The drive rated is 4 kw and the motor rated is 0.9amps/380volts/1360rpm/0.25kw/50hz.

The drive is operating in v/f mode.

Based on my application, i will pick the corresponding contactor and I will vary the motor frequency from 2 Hz to 75 Hz. At different point of time, The motor will run at this frequency range. I have used MPCB of 0.6 to 1 amps at the drive output. I am operating the drive at 4 KHz pulse frequency and my MPCB is getting heated up and nussence tripping is happening. As per the skin effect and pulse frequency, i applied the correction factor and increased the MPCB rating to 1 - 1.6 amps ans set the mpcb to 1.2 amps. But still mpcb is heating up and system is tripping at lower frquencies.

Can anybody suggest to have the right solution for this problem?

Thanks & Regards

CRS
Register to Reply
Pathfinder Tags: mpcb for drive output
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
JRaef
Guru
United States - Member - New Member Engineering Fields - Power Engineering - New Member

Join Date: Sep 2006
Location: California, USA, where the Godless live next door to God.
Posts: 4665
Good Answers: 804
#1

Re: MPCB for Drive Output Selection

07/28/2012 10:44 AM

Do you have a reactor on the output of the drive before you split off to the 10 MPCBs? If not, start there, it's almost mandatory. Also, what is the MPCB? Is it the Siemens 3RA6? if so, that's an electronic trip and I don't believe it is suitable for PWM power.

__________________
 ** All I every really wanted to be, was... A LUMBERJACK!.**
Register to Reply
expertsuresh
Participant

Join Date: Jun 2012
Posts: 3
#2
In reply to #1

Re: MPCB for Drive Output Selection

07/29/2012 3:54 AM

Thanks for your feedback.

I do not have reactor in the drive output. MPCB is the motor protection circuit breaker of siemens make of model no 3VU13401MF00 - MPCB 3VU with 1NO + 1NC: Rated Voltage 415V,Rated current 1A,overload release 0.6-1A,s/c release 12A.

The drive output goes to busbar and then it splits to MPCB.

Can you guide me to select the right reactor?

I tried with higher rating mpcb as per impedence calculation and in the drive the current drawn is showing 0.5 amps. But MPCB is heating up. I tried with MCB and it is working perfect. I have put MCB only for short circuit stage. My drive will trip on overload situation.

Regards

CRS
Register to Reply
JRaef
Guru
United States - Member - New Member Engineering Fields - Power Engineering - New Member

Join Date: Sep 2006
Location: California, USA, where the Godless live next door to God.
Posts: 4665
Good Answers: 804
#3

Re: MPCB for Drive Output Selection

07/29/2012 12:04 PM

You can just select the output reactor for the total output capacity of the drive. Any vendor can do that for you.

__________________
 ** All I every really wanted to be, was... A LUMBERJACK!.**
Register to Reply
expertsuresh
Participant

Join Date: Jun 2012
Posts: 3
#4
In reply to #3

Re: MPCB for Drive Output Selection

07/29/2012 12:27 PM

I will add reactor in my circuit and i will update you accordingly.

Thanks for your valuable feedback
Register to Reply
Register to Reply
Have a Different Question?
4 comments

Previous in Forum: Pump Operation   Next in Forum: Thyristor for Voltage Regulator

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Electrical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (42 right now)
Show Members
Advertisement