Four quadrant control of series motors
OwnerBonne W. Posmainventor
Life of this patent
Estimating the term…
Abstract
A method of controlling and a controller for controlling at least one series motor is provided. Rectifier means is connected in series with the motor so that current through a field winding of the motor is always in the same direction irrespective of the polarity of the input voltage while the current direction through an armature of the motor reverses in accordance with the polarity of the input voltage. An energizing current is applied to the field winding by a bias power supply to ensure that the field winding always produces some flux during operation of the motor.
Claims16
A method of controlling at least one series motor which includes connecting rectifier means in series with the motor so that current through a field winding of the motor is always in the same direction irrespective of the polarity of the input voltage while the current direction through an armature of the motor reverses in accordance with the polarity of the input voltage, applying an energizing current to the field winding to ensure that the field winding always produces some flux during operation of the motor, and detecting a regenerative condition of the motor, and when detected, causing a switching action to take place to isolate the field winding from the armature thereby to change the series motor to an equivalent shunt motor.
A controller for controlling at least one series motor, the controller comprising:
- control means operable to vary the polarity and voltage supplied to the motor, rectifier means intermediate the control means and the motor and operable to supply current in one direction only through a field winding of the motor irrespective of the polarity of the voltage supplied by the control means and operable to supply current with reversible polarity to an armature of the motor in accordance with the polarity of the voltage as supplied by the control means, a bias power supply connectable to the field winding and operable to produce field flux during all stages of operation of the motor, and detection means operable to detect a regenerative condition of the motor and operable when such a condition is detected to operate a switch means thereby to isolate the field winding from the armature to change the series motor to an equivalent shunt motor during regeneration.
A method of controlling at least one series motor, comprising:
- connecting rectifier means in series with the motor so that current through a field winding of the motor is always in the same direction irrespective of the polarity of the input voltage while the current direction through an armature of the motor reverses in accordance with the polarity of the input voltage;
- applying an energizing current to the field winding by means of a bias supply to ensure that the field winding always produces some flux during operation of the motor so that counter EMF exists when the motor rotates, whether or not armature current flows;
- detecting a regenerative condition of the motor;
- and isolating the field winding from the armature when a regenerative condition is detected.
A controller for controlling at least one series motor, the controller comprising:
- control means operable to vary the polarity and voltage supplied to the motor;
- rectifier means intermediate the control means and the motor for supplying current in one direction only through a field winding of the motor irrespective of the polarity of the voltage supplied by the control means and for supplying current with reversible polarity to an armature of the motor in accordance with polarity of the voltage as supplied by the control means;
- bias power supply means connectable to the field winding for producing field flux during all stages of operation of the motor to produce counter EMF when the motor rotates, whether or not armature current flows;
- and
- means for detecting a regenerative condition of the motor and for operating a switch means when said regenerative condition is detected to isolate the field winding from the armature.
Dependencies are inferred from the claim text.