Soft start system for motors utilizing variable frequency drive and autotransformer
AssigneeConverteam Ltd
InventorDavid Rudniski
Life of this patent
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Abstract
A soft start system for starting large motors has a power supply suitable for passing power to the motor, a variable frequency drive connected to the power supply and an autotransformer connected between the variable frequency drive and the motor for passing power of an elevated current to the motor. A switch is connected between the motor and power supply for connecting the motor to the power supply when the motor reaches a desired speed. The autotransformer includes a single core with a winding extending over the single core. The autotransformer includes a first terminal connected the variable frequency drive, a second terminal connected the motor and a grounded neutral.
Claims17
A soft start system comprising:
- a motor;
- a power supply means for passing power of a first voltage and a first current and a first frequency;
- a variable frequency drive connected to said power supply;
- and
- an autotransformer means connected between said variable frequency drive and said motor for passing power of a second voltage and a second current and a second frequency to said motor, said second voltage and said second frequency being less than said first voltage and said first frequency, said second current being higher than said first current.
A process for starting a motor from a power supply comprising:
- passing power from the power supply of a first frequency and a first voltage and a first current to a variable frequency drive;
- passing the power from the variable frequency drive to an autotransformer;
- autotransforming the power by said autotransformer such that the power is of a second frequency that is less than said first frequency and a second voltage that is less than said first voltage and a second current that is higher than a first current;
- and
- passing the autotransformed power to said motor so as to start the motor.
Dependencies are inferred from the claim text.