Shunt-type speed control circuit having transient storage effect for a series or compound motor
OwnerTai-Her Yanginventor
Life of this patent
Estimating the term…
Abstract
The series field winding of a compound or series motor includes a plurality of taps and, connected in parallel therewith, a transient storage element such as a capacitor, and a flywheel diode. The taps are controlled by switches in the form of transistors or thyristors which are turned on and off by a central control unit in response to setting of the speed and, optionally, various feedback devices such as a motor speed detector, an armature EMF detector, or a load current detector. The transient storage device replaces conventional linear impedance or linear power elements in order to prevent loss of power as the armature voltage is increased.
Claims9
A shunt-type motor speed control circuit, comprising:
- a direct current motor armature;
- a series field winding having a first end connected to a terminal of a diode and a second end connected to the armature;
- at least one tap on the series field winding and at least one switch connected between the tap and a power supply terminal, said diode being connected in series between the power supply terminal and the first end of the series field winding;
- means for controlling said switch to selectively connect said tap with said connection point and thereby change the effective turn ratio of said series winding;
- and
- transient energy storage means connected in parallel with the series field winding for enabling the series winding to maintain a stable excitation field during switching of said switch.
Dependencies are inferred from the claim text.