Jump to content


Soft Starter

  • Please log in to reply
2 replies to this topic

#1 Niranjan


  • Members
  • Pip
  • 1 posts

Posted 14 December 2009 - 10:44 AM

Hi !
Normally the soft starter manufacturers claims for Energy save with their decise ! and may be effective when motor is underloaded appx 40% but in a case where motor is 80 % loaded and working with full efficiency .

Do enebling of Energy save is advisable ? Will the device work as energy saver or more as a Losser ....... as it increase in Harmonics distortions in line as signal no more remains pure sine what will be ratio for Cu losses , Iron Losses , Windage losses compared to the wastage energy saved ..........

#2 Steven1984


    Junior Member

  • Full Member
  • PipPip
  • 7 posts

Posted 16 December 2009 - 08:52 AM

Hi Niranjan,

If a motor is loaded at 80% then the opportunity for saving energy will be small.

There will be a slight amount of harmonic distortion but this is small, the added loses for the soft starters are generally 1 Watt per Amp per Phase.

To negate these affect a bypass contactor could be used.



#3 marke


    Posting Freak

  • Moderator
  • PipPipPipPipPipPip
  • 2,641 posts
  • Gender:Male
  • Location:Christchurch, New Zealand

Posted 16 December 2009 - 05:44 PM

Hello Niranjan

The energy saver only reduces the magnetising losses in the motor and this only works when the total current is close to the magnetising current of the motor.
Only use this feature if the motor a) has high magnetising losses, and cool.gif if the motor operates for a significant period of time under idle conditions.
See http://www.LMPhotonics.com/energy.htm

Best regards,

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users