System and method for bypassing a motor drive
First Claim
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1. A motor control system for an electric motor, comprising:
- a bypass switch comprising;
a first set of contacts electrically coupled in series between a power source and an input of a variable frequency drive;
a second set of contacts electrically coupled in series between an output of the variable frequency drive and a load;
an operator having a first position and a second position, wherein the first set of contacts and the second set of contact are closed when operator is oriented in the first position and the first set of contacts and the second set of contacts are open when the operator is oriented in the second position;
a bypass contactor having a set of bypass contacts, wherein the set of bypass contacts is electrically coupled in parallel with the first set of contacts and the second set of contacts between the power source and the load; and
the switch being configured to energize the bypass contactor and thereby close the set of bypass contacts when the first and second sets of contacts are open.
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Abstract
A motor control system comprising a plurality of motor controllers and a power source adapted to drive an electric motor. The motor control system comprises a switch that is selectively operable between at least a first position and a second position. In the first position, the power source is coupled to a first controller to provide the power to drive the electric motor. In the second position, the power source is coupled to a second controller to provide the power to drive the electric motor. The switch also electrically isolates the input and the output of the first controller from the power source when the manual bypass switch is positioned in the second position.
54 Citations
21 Claims
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1. A motor control system for an electric motor, comprising:
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a bypass switch comprising; a first set of contacts electrically coupled in series between a power source and an input of a variable frequency drive; a second set of contacts electrically coupled in series between an output of the variable frequency drive and a load; an operator having a first position and a second position, wherein the first set of contacts and the second set of contact are closed when operator is oriented in the first position and the first set of contacts and the second set of contacts are open when the operator is oriented in the second position; a bypass contactor having a set of bypass contacts, wherein the set of bypass contacts is electrically coupled in parallel with the first set of contacts and the second set of contacts between the power source and the load; and the switch being configured to energize the bypass contactor and thereby close the set of bypass contacts when the first and second sets of contacts are open. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A motor control system, comprising:
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a variable frequency drive adapted to produce a variable frequency output to control the speed of a motor, the variable frequency drive comprising; an input to enable power from an external power source to be coupled to the variable frequency drive; and an output to enable the variable frequency drive to be coupled to the motor; and an electrical system operable to selectively couple the motor to the output of the variable frequency drive and the external power source, the electrical system being adapted to electrically isolate the input and the output of the variable frequency drive from the external power source when the motor is coupled to the external power source; wherein the electrical system comprises a manual bypass switch and a bypass contactor;
the bypass contactor having at least one set of contacts electrically connected in parallel with the variable frequency drive and electrically connected in series between the external power source and the motor; and
wherein the manual bypass switch has a first set of contacts electrically connected in series to the input of the variable frequency drive and a second set of contacts electrically connected in series to the output of the variable frequency drive. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A motor control system, comprising:
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a variable frequency drive adapted to produce a variable frequency output to control the speed of a motor; a bypass switch having first and second sets of contacts for electrically coupling the variable frequency drive to a external power source and to the motor, and a set of auxiliary contacts; a bypass contactor having a set of bypass contacts, the bypass contactor configured to be energized by the auxiliary contacts to electrically coupled the motor to the external power source such that the bypass contacts are electrically parallel to the variable frequency drive. - View Dependent Claims (16, 18, 19, 20)
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17. The motor control system of 15, wherein the bypass switch has a first position and a second position;
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the first position enabling the variable frequency drive; and the second position isolating the variable frequency drive.
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21. A system comprising:
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a motor drive operable to drive an electric motor; a bypass contactor electrically in parallel with the motor drive; a motor control system comprising a manual bypass switch selectively operable to couple the motor drive between a power source and the electric motor, wherein the manual bypass switch is operable to electrically isolate the motor drive from the power source and from the motor, and to close the bypass contactor to couple the motor directly to the power source; and a set of contacts electrically coupled in series with the bypass contactor for opening the contactor before the motor drive is recoupled between the power source and the motor.
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Specification