Locomotive wheel slip control

• US 3,982,164 A
• Filed: 12/18/1974
• Issued: 09/21/1976
• Est. Priority Date: 12/18/1974
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Meyer, Bruce R., de Buhr, Alfred P.
• Primary Examiner(s): Dobeck, B.
• Application Number:
  US05/534,078
• Time in Patent Office: 643 Days
• Field of Search: 318/52
• US Class Current: 318/52
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 3/10 Indicating wheel slip ; Correction of wheel slip
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02

Abstract

A method and apparatus are disclosed for controlling the wheel slip of an electric or diesel electric locomotive such that optimum wheel adhesion may be attained. A certain characteristic of a series traction motor, specifically the back emf per rpm versus motor current (E/n vs. I), forms the basis for a voltage control which limits the voltage (V) supply to each motor to a value which will limit the maximum percentage wheel slip. The selected limit value of wheel slip is great enough to encompass the conditions of maximum adhesion under most rail conditions. By combining the E/n with the motor IR drop, motor current, and a locomotive speed signal, the idealized voltage V for a non-slip condition is derived. This voltage is increased by a factor representing the desired maximum percentage slip to obtain the limiting voltage which may be supplied to the motor. A current maximizing circuit is included to decrease the allowed percent slip from the maximum preselected value to a value which provides the maximum motor current to obtain maximum traction.

Claims

1. A wheel slip control for a locomotive having a power supply and an electrical traction motor driving locomotive wheels subject to slipping for limiting the maximum percent wheel slip comprising

means coupled to the motor for providing a current signal I corresponding to the motor current,

means for providing a speed signal n corresponding to motor speed for a non-slipping condition of the motor,

a function generator connected to respond to said current signal I programmed to produce an output signal as a function of I representing E/n where E is back emf of the motor,

and a circuit having as inputs said current signal, said speed signal and said E/n signal operative to calculate and produce from said inputs a limit voltage a programmed amount in excess of V = E + IR where V is the voltage of the motor for a non-slipping condition and R is motor resistance, and the programmed amount in excess of V represents a desired percent slip, and

means responsive to said limit voltage for limiting the maximum voltage supplied to the motor to a value corresponding to said limit voltage thereby establishing a maximum percent slip of wheels driven by the motor.

2. A wheel slip control for a locomotive having a power supply and several electrical traction motors driving wheels subject to slipping for limiting the maximum percent wheel slip comprising

means coupled to the several motors for providing a current signal I corresponding to the lowest motor current of the several motors,

means for providing a speed signal n corresponding to motor speed for a non-slipping condition,

a function generator connected to respond to said current signal I programmed for providing an output signal as a function of I representing E/n where E is back emf of the motor,

and a circuit having an inputs said current signal, said speed signal and said E/n signal operative to calculate and produce from said inputs a signal V = E + IR where V is the voltage of the motors for a non-slipping condition and R is motor resistance,

means for increasing the V signal by a factor representing desired maximum percent slip to obtain a limit voltage, and

means responsive to said limit voltage for limiting the maximum voltage supplied to the motors to a value corresponding to said limit voltage thereby establishing a maximum percent slip of wheels driven by the motors.

3. A wheel slip control for a locomotive having a power supply and several electrical traction motors driving wheels subject to slipping for limiting the maximum percent wheel slip comprising

means for providing a current signal I corresponding to the lowest motor current of the several motors,

means for providing a speed signal n corresponding to motor speed for a non-slipping condition,

a function generator responsive to the current signal programmed for providing an output signal representing E/n where E is back emf of the motor, and

a circuit for calculating from the current signal, the speed signal and the E/n signal V = E + IR where V is the voltage of the motors for a non-slipping condition and R is motor resistance,

means for increasing the V signal by a factor representing desired maximum percent slip to obtain a limit voltage, and

means for limiting the maximum voltage supplied to the motors to the value of the limit voltage thereby establishing a maximum percent slip of wheels driven by the motors, and

a maximizing circuit responsive to combined motor current of the several motors for modifying the limit voltage to increase the combined motor current to substantially its maximum value within the limit of the desired maximum wheel slip.

4. A wheel slip control for a locomotive having a power supply and several electrical traction motors driving wheels subject to slipping for limiting the maximum percent wheel slip comprising

means for providing a current signal I corresponding to the lowest motor current of the several motors,

means for providing a speed signal n corresponding to motor speed for a non-slipping condition,

a function generator responsive to the current signal programmed for producing an output signal representing E/n where E is back emf of the motor,

a second function generator responsive to the current signal for producing an output signal representing IR where R is the motor resistance,

a multiplier circuit responsive to the E/n signal and the speed signal for producing a signal proportional to E,

means for combining the outputs of the second function generator and the multiplier circuit for producing a signal V representing the motor voltage for a non-slipping condition,

means for increasing the V signal by a factor representing desired maximum percent slip to obtain a limit voltage, and

means for limiting the maximum voltage supplied to the motors to the value of the limit voltage thereby establishing a maximum percent slip of wheels driven by the motors.

5. A wheel slip control for a locomotive having a power supply and several electrical traction motors driving wheels subject to slipping for limiting the maximum percent wheel slip comprising

means for providing a current signal I corresponding to the lowest motor current of the several motors,

means for providing a speed signal n corresponding to motor speed for a non-slipping condition,

a function generator responsive to the current signal programmed for producing an output signal representing E/n where E is back emf of the motor,

a second function generator responsive to the current signal for producing an output signal representing IR where R is the motor resistance,

a multiplier circuit responsive to the E/n signal and the speed signal for producing a signal proportional to E,

means for combining the outputs of the second function generator and the multiplier circuit for producing a signal V representing the motor voltage for a non-slipping condition,

means for increasing the V signal by a factor representing desired maximum percent slip to obtain a limit voltage,

means for limiting the maximum voltage supplied to the motors to the value of the limit voltage thereby establishing a maximum percent slip of wheels driven by the motors, and

a maximizing circuit responsive to combined motor current of the several motors for modifying the limit voltage to increase the combined motor current to substantially its maximum value within the limit of the desired maximum wheel slip.