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Calculating Of Currents In Dol And Star-delta?, Calculation of currents in DOL and star delta? |
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 Jun 23 2009, 10:33 PM
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#1
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 Group: Members Posts: 1 Joined: 23-June 09 Member No.: 5,623  |
What are the formulae to calculate Line currents in DOL and star -delta starters?
How can we say that in star-delta starter the currents through the windings are 1/root3 of line current? Please explain. |
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Jul 2 2009, 02:55 AM
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#2
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Intermediate Member Group: Full Member Posts: 37 Joined: 28-September 08 From: Kuala Lumpur Member No.: 4,848 |
Upon reaching rated speed, line current of motors using both direct online starter and star delta starter are the same.
I = P / sqrt(3) x U x cos a I is the line current of the motor. P is the input power to the motor. (Usually stated on the motor nameplate) U is the line to line voltage. cos a is the power factor of the motor. (Usually stated on the motor nameplate) As for the star delta starter, during start The line current is 1/sqrt(3) because the voltage is reduced by 1/sqrt(3) as the motor winding is in star configuration. Regards, Kana |
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Jul 4 2009, 05:43 AM
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#3
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Posting Freak Group: Moderator Posts: 2,383 Joined: 24-April 02 From: Christchurch, New Zealand Member No.: 1 |
Hello dinesh
have a look at http://www.lmphotonics.com/m_start.htm and http://www.lmphotonics.com/m_control.htm Best regards, Mark. -------------------- Mark Empson administrator
Skype Contact = markempson | phone +64 274 363 067 LMPForum | LMP Tech Warehouse | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | LMP Software | Mark Empson Website |
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