Motor control apparatus and method
AssigneeWestinghouse Electric Corp.
InventorThomas C. Matty
Life of this patent
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Abstract
A direct current motor controlling apparatus determines the operational speed of one or more direct current motors such as traction motors propelling a passenger vehicle along a track. The speed of the motor is established by changing the on and off conduction ratio or duty-cycle relationship of a switch device to determine the field current and the armature voltage of that motor. The present apparatus utilizes solid-state switch devices to determine the mode of operation of the motor control apparatus which solid-state switch devices are more reliable and more simple in operation and less expensive to maintain.
Claims10
In control apparatus operative with a voltage source for determining one of a power mode of operation and a brake mode of operation for a motor coupled to a load and including a field winding and an armature, the combination of:
- first switch means connected with said voltage source to provide a first current circuit to establish said power mode by energizing said field winding and energizing said motor armature in a first direction in relation to said voltage source when the first switch means is conducting,
- second switch means connected with said voltage source to provide a second current circuit to establish said brake mode by energizing said field winding and energizing said motor armature in a second direction in relation to said voltage source when the second switch means is conducting,
- control means coupled with said first switch means to make the first switch means conductive to determine said power mode of operation for the motor and coupled with the second switch means to make the second switch means conductive to determining said brake mode of operation for the motor, with said control means coupled with each of said first switch means and said second switch means to make both the first switch means and the second switch means conductive for providing a third current circuit for energizing said field winding without energizing said armature in relation to said voltage source, and
- conduction determining means operative with the first switch means to determine the conductivity of the first switch means in relation to the second switch means for establishing said brake mode of operation for said motor.
In the method of controlling in each of a power mode and a brake mode the operation of a motor having a field winding and an armature coupled with a power supply, the steps of:
- operating a first switch in the power mode to be conductive in one circuit arrangement including the power supply, the field winding and the armature for providing current through the armature in a first direction;
- operating both the first switch and a second switch between operation in the power mode and in the brake mode to be conductive in another circuit arrangement including the power supply and the field winding for providing current through the field winding;
- and
- terminating the operation of the first switch while continuing the operation of the second switch in the brake mode to be conductive in a different circuit arrangement including the field winding and the armature for providing current through the armature in a second direction.
In the method of controlling a motor for a moving vehicle and having a field winding and an armature, said motor being coupled with a power supply, the steps of:
- providing a power mode of operation for said motor to move said vehicle by providing a first current path including the field winding and the armature and with the current flow through the armature being in a first direction;
- providing a brake mode of operation for said motor to brake said vehicle by providing a second current path including the field winding and the armature and with the current flow through the armature being in a second direction;
- and
- providing a change-over for the moving vehicle from the power mode to the brake mode by providing a third current path including the field winding without the armature.
Dependencies are inferred from the claim text.