Three-Phase Induction Motor Starters, 1 DOL Starters … ZKHQ \RX VWDUW D PRWRU XVLQJ HLWKHU RQH RI...
Transcript of Three-Phase Induction Motor Starters, 1 DOL Starters … ZKHQ \RX VWDUW D PRWRU XVLQJ HLWKHU RQH RI...
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Overcurrent protection. Overload protection.
Start up current. Consequences of extended large currents. Voltage sag. Start-up torque.
Voltage output of a soft starter. Effect of the soft starter on the motor current. Effect of the soft starter on the motor torque. Effect of the soft starter on the motor speed. How a soft starter controls voltage. Bypass circuit. Types of soft starters.
Introduction
Direct-on-line starters
DOL Starters and Soft Starters
Exercise 1
EXERCISE OBJECTIVE
DISCUSSION OUTLINE
DISCUSSION
Exercise 1 – DOL Starters and Soft Starters Discussion
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Motor protections
Overcurrent protection
Exercise 1 – DOL Starters and Soft Starters Discussion
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Overload protection
Exercise 1 – DOL Starters and Soft Starters Discussion
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Exercise 1 – DOL Starters and Soft Starters Discussion
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Motor start-up phenomena
Start up current
Exercise 1 – DOL Starters and Soft Starters Discussion
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Consequences of extended large currents
Exercise 1 – DOL Starters and Soft Starters Discussion
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Voltage sag
Start-up torque
Exercise 1 – DOL Starters and Soft Starters Discussion
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Soft starters
Exercise 1 – DOL Starters and Soft Starters Discussion
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Voltage output of a soft starter
Exercise 1 – DOL Starters and Soft Starters Discussion
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Effect of the soft starter on the motor current
Exercise 1 – DOL Starters and Soft Starters Discussion
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Effect of the soft starter on the motor torque
Poly. (DOL)
Poly. (SS)
Exercise 1 – DOL Starters and Soft Starters Discussion
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Effect of the soft starter on the motor speed
Exercise 1 – DOL Starters and Soft Starters Discussion
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How a soft starter controls voltage
Poly. (Speed DOL
(rev/min))
Poly. (SS)
Exercise 1 – DOL Starters and Soft Starters Discussion
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Exercise 1 – DOL Starters and Soft Starters Discussion
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Bypass circuit
Types of soft starters
Exercise 1 – DOL Starters and Soft Starters Discussion
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Exercise 1 – DOL Starters and Soft Starters Procedure Outline
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Setup and connections
In this part of the exercise, you will connect your equipment as a DOL starter, configure parameters in LVDAC-EMS so that the Four-Quadrant Dynamometer/Power Supply emulates a flywheel, and set the Oscilloscope to observe the motor start-up current, torque, and speed.
Power Input
Power Input
Low Power Input Power Input
PROCEDURE OUTLINE
PROCEDURE
Exercise 1 – DOL Starters and Soft Starters Procedure
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Operating Mode Dynamometer
Computer-Based Instrumentation Thyristor Control
OK
Tools Friction Compensation Calibration
OK
OK
O I
I1
a Current input I4 of the Data Acquisition and Control Interface is used to monitor the motor current in order to protect the motor from overheating if excessive currents flow through the stator windings. The range of current to be used for current input I4 is 40 A.
Exercise 1 – DOL Starters and Soft Starters Procedure
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I1
I1
Sync.
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Digital Output 1 DO1 D+ – Remote Control
Analog Outputs T nAnalog Inputs /T /n
Analog OutputsA
Function Mechanical Load
Load Type Flywheel
Inertia
Friction Torque
Pulley Ratio
a Note that the pulley ratio between the Four-Quadrant Power Supply/Dynamometer and the Four-Pole Squirrel Cage Induction Motor is 24:24.
Function Direct On-Line Starter
Motor Full Load Current [FLA]
Overload On
Overload Class
Exercise 1 – DOL Starters and Soft Starters Procedure
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I1)Analog Input 7/T
Analog Input 8/n
Peak Detect
Starting an induction motor using a DOL starter
In this part of the exercise, you will start the motor using a DOL starter. You will record the motor current, torque, and speed at start-up and analyze the results.
Status StartedStart/Stop
Single RefreshStart
a The above manipulation must be performed rapidly to ensure that the Oscilloscope records the entire evolution of the various parameters during motor start-up.
Stop
a Since the Oscilloscope operates in peak detect mode and a slow time base is used, it displays the envelope of the motor current rather than its waveform.
Status StoppedStart/Stop
Exercise 1 – DOL Starters and Soft Starters Procedure
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a The maximal current obtained in step 22 is a peak value. Convert this peak value to an rms value before making the comparison.
Exercise 1 – DOL Starters and Soft Starters Procedure
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Soft starter setup and settings
In this section, you will modify the equipment connections so as to replace the DOL starter with a soft starter.
I1
Exercise 1 – DOL Starters and Soft Starters Procedure
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I1
Exercise 1 – DOL Starters and Soft Starters Procedure
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Sync.
Digital Output 1Remote Control
T and n Analog OutputsAnalog Inputs 7/T 8/n
Digital OutputsFiring Control Inputs
Range I1
Function Soft Starter
Mode Soft Start
Motor Full Load Current [FLA]
Initial Torque
Start TimeSoft Starter
Initial Torque
Kick Start Time
Soft Stop
Overload On
Overload Class
Exercise 1 – DOL Starters and Soft Starters Procedure
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Starting an induction motor using a soft starter
In this part of the exercise, you will start the motor, still coupled to the same mechanical load used earlier in the exercise, using a soft starter. You will record the motor current, torque, and speed at start-up and analyze the results.
Single RefreshStart
a The above manipulation must be performed rapidly to ensure the Oscilloscope records the entire evolution of the various parameters during motor start-up.
Stop
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DOL starter versus soft starter
In this part of the exercise, you will compare the results you obtained with the DOL starter and the soft starter (for the same mechanical load) and try to deduce what the advantages and limitations of each one are.
Exercise 1 – DOL Starters and Soft Starters Conclusion
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ToolsReset to Default Friction Compensation
Yes
CONCLUSION
REVIEW QUESTIONS
Exercise 1 – DOL Starters and Soft Starters Review Questions
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