Slip Ring Motors With Vfd |
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Slip Ring Motors With Vfd |
Dec 8 2006, 01:50 PM
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#1
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Junior Member ![]() ![]() Group: Members Posts: 4 Joined: 7-December 06 Member No.: 2,641 |
WE HAVE SLIP RING MOTOR WITH 2.2KW ANALOG DRIVE WITH PERMANENT ROTOR RESISTORS CONNECTED FOR CRANE TROLLEY MOTOR.DUE TO ANALOG FREQUENT CONTROL CARD PROBLEM
NOW WE HAVE CONNECTED SLIP RING MOTOR WITH VFD WITH SAME ROTOR RESISTORS CONNECTED PERMANENTLY.BUT WHEN RUNNING IN VFD MOTOR TAKES HIGH CURRENT .SHOULD WE TAKE OUT THE ROTOR RESISTORS AND TO SHORT THE ROTOR RESISTOR TERMINALS AT THE MOTOR END TO REDUCE THE CURRENT. ANY ONE CAN GIVE THE SOLUTION BYE |
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Dec 9 2006, 11:33 PM
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#2
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Posting Freak ![]() ![]() ![]() ![]() ![]() ![]() Group: Moderator Posts: 2,118 Joined: 24-April 02 From: Christchurch, New Zealand Member No.: 1 |
Hello MSBALA
The connection of rotor resistors when using a ship ring motor with a VSD should not increase the current flowing, rather, it will increase the slip for a given shaft torque. If you short out the resistors, the current should remain the same, but the motor should run closer to the speed of the VFD. The higher current would usually be the result of an incorrect setting, particularly, the output voltage is higher than it should be for that motor. In the VFD setup, there should be a parameter for the motor frequency and the motor voltage. If these do not match the motor ratings, there will be an incorrect output voltage and this will increase the output current. Best regards, -------------------- 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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Dec 12 2006, 02:40 AM
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#3
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Senior Member ![]() ![]() ![]() ![]() ![]() Group: Full Member Posts: 223 Joined: 21-October 06 Member No.: 2,159 |
QUOTE(MSBALA @ Dec 8 2006, 06:50 PM) [snapback]5232[/snapback] WE HAVE SLIP RING MOTOR WITH 2.2KW ANALOG DRIVE WITH PERMANENT ROTOR RESISTORS CONNECTED FOR CRANE TROLLEY MOTOR.DUE TO ANALOG FREQUENT CONTROL CARD PROBLEM NOW WE HAVE CONNECTED SLIP RING MOTOR WITH VFD WITH SAME ROTOR RESISTORS CONNECTED PERMANENTLY.BUT WHEN RUNNING IN VFD MOTOR TAKES HIGH CURRENT .SHOULD WE TAKE OUT THE ROTOR RESISTORS AND TO SHORT THE ROTOR RESISTOR TERMINALS AT THE MOTOR END TO REDUCE THE CURRENT. ANY ONE CAN GIVE THE SOLUTION BYE Dear MSBALA, Please always post your question in small fonts which is easy to read in a short time. -------------------- "Don't assume any thing, always check/ask and clear yourself".
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Dec 12 2006, 02:58 PM
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#4
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Member ![]() ![]() ![]() ![]() Group: Full Member Posts: 153 Joined: 26-February 06 From: Midwest, USA Member No.: 1,401 |
QUOTE(MSBALA @ Dec 8 2006, 07:50 AM) [snapback]5232[/snapback] NOW WE HAVE CONNECTED SLIP RING MOTOR WITH VFD WITH SAME ROTOR RESISTORS CONNECTED PERMANENTLY.BUT WHEN RUNNING IN VFD MOTOR TAKES HIGH CURRENT .SHOULD WE TAKE OUT THE ROTOR RESISTORS AND TO SHORT THE ROTOR RESISTOR TERMINALS AT THE MOTOR END TO REDUCE THE CURRENT. What was the running current before using the VFD ? What is the mains voltage ? Is the motor connected for that voltage ? Advise, -------------------- jΩ
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Lo-Fi Version | Time is now: 10th January 2009 - 03:09 AM |