Functions
7.6 Motor control
Frequency inverters with Control Units CU230P-2 HVAC, CU230P-2 DP, CU230P-2 CAN
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Operating Instructions, 01/2011, FW 4.4, A5E02430659B AD
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7.6
Motor control
For induction motors, there are two different open-loop control or closed-loop control
techniques:
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Open-loop control with V/f-characteristic (V/f control)
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Field-oriented control (vector control)
Criteria for selecting either V/f control or vector control
V/f control is perfectly suitable for almost any application in which the speed of induction
motors is to be changed. Examples of typical applications for V/f control include:
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Pumps
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Fans
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Compressors
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Horizontal conveyors
Commissioning vector control takes more time than when commissioning V/f control. When
compared to V/f control, vector control offers the following advantages:
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The speed is more stable for motor load changes.
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Shorter accelerating times when the setpoint changes.
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Acceleration and braking are possible with an adjustable maximum torque.
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Improved protection of the motor and the driven machine as a result of the adjustable
torque limiting.
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The full torque is possible at standstill.
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Torque control is only possible with vector control.
Examples of typical applications in which vector control is used:
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Hoisting gear and vertical conveyors
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Winders
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Extruders
Summary of Contents for SINAMICS G120 CU230P-2
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