Motor controlling

• US 4,347,466 A
• Filed: 12/27/1979
• Issued: 08/31/1982
• Est. Priority Date: 05/10/1978
• Status: Expired due to Term

• Current Assignee: Furnas Electric Co. (Siemens AG)
• Original Assignee: VEE Arc Corporation
• Inventors: Ottoson, Allen E.
• Primary Examiner(s): Weldon, Ulysses
• Application Number:
  US06/107,595
• Time in Patent Office: 978 Days
• Field of Search: 318/269, 318/376, 318/379, 318/380, 318/509, 318/512, 318/301, 318/510, 318/511, 318/419, 318/815, 318/438.1, 318/339, 318/342, 318/343, 323/89 AG, 323/345 A, 323/345 C
• US Class Current: 388/806
• CPC Class Codes: H02P 7/281 the DC motor being operated in four quadrants
• CPC Class Codes: Y10S 388/902 Compensation
• CPC Class Codes: Y10S 388/917 Thyristor or scr

Abstract

D.C. motor control utilizing an input transformer with magnetic leakage and current control to allow power, whether generated occasionally or continuously from the motor (induced by load inertia and the like) to be smoothly returned back into the main A.C. power line, consistent with continuous smooth speed control (low form factor), low heating and low cost.

Claims

1. A DC motor system operable in motor and generator modes and comprising:

an AC source for delivering AC power,

a DC motor having a motor field and an armature,

rectifier means including at least one pair of oppositely poled controlled rectifiers and an armature capacitor coupled from said controlled rectifiers and disposed across said armature,

said rectifier means connected to receive AC power from said AC source and to rectify said AC to DC across said armature capacitor,

controller means including means coupled from the AC source and means responsive to armature voltage magnitude for controlling the triggering of one of said controlled rectifiers to enable current flow for normal motor operation of the armature and for alternatively and mutually exclusively controlling the triggering of the other of said controlled rectifiers to enable the generator mode,

inductive reactanct means including a field conductor,

and electrical conductor means interconnecting in series said AC source, field conductor and rectifier means,

said field conductor providing a magnetic circuit leakage path coupled in series between the AC source and the rectifier means to apply power generated in the armature back into the AC source via the magnetic leakage path as well as applying power input to the armature in motoring.

2. A motor system as set forth in claim 1 wherein said armature capacitor and inductive reactance means form a current smoothing filter.

3. A motor system as set forth in claim 1 wherein said inductive reactance means creates a negative slope DC voltage-current waveform of armature operation whereby maximum motor current is limited to ten times full load current.

4. A motor system as set forth in claim 1 wherein said rectifier means includes a full wave rectifier comprising two pairs of oppositely poled controlled rectifiers.

5. A motor system as set forth in claim 1 wherein said means providing a magnetic circuit path includes a center-taped transformer.

6. A motor system as set forth in claim 5 wherein said rectifier means includes a full wave rectifier comprising two pairs of oppositely poled controlled rectifiers.

7. A motor system as set forth in claim 1 wherein said inductive reactance means is sized and arranged to limit maximum armature current to 10 times full load current.

8. A motor system as set forth in claim 7 wherein the maximum armature current is limited to 5 times full load current.

9. A motor system as set forth in claim 1 wherein said magnetic circuit leakage path includes metal shunt means.

10. A motor system as set forth in claim 1 wherein said inductive reactance means includes a part metal, part air-gap magnetic field conductor.

11. A motor system as set forth in claim 1 including feedback means responsive to armature voltage for controlling operation of said controller means, the armature signal at one state causing said one controlled rectifier operation and in another state causing said other controlled rectifier operation.

12. A motor system as set forth in claim 1 wherein said inductive reactance means includes a magnetic field conductor having means for providing a radial magnetic leakage path creating a negative slope DC voltage-current waveform of armature operation whereby maximum motor current is limited to ten times full load current, said rectifier means comprising a full wave rectifier including two pairs of oppositely poled controlled rectifiers, said means coupling the AC source to the rectifier means including transformer means having a primary for receiving the AC source power and at least one secondary winding separated physically from the primary winding by said inductive reactance means, said controller means including feedback means responsive to an armature signal for controlling operation of said controlled rectifiers, the armature signal at one state causing said one controlled rectifier of each pair to operate for motoring mode and in another state causing said other controlled rectifier of each pair to operate for generating mode.

13. A motor system as set forth in claim 12 wherein said transformer means has a first secondary winding for providing power to the motor field, a second secondary winding and associated supply for operating said controller means, and a third secondary winding forming a part of the full wave bridge and being center-tapped having a common lead coupled to the armature and first and second end leads coupling respectively to the first and second pairs of oppositely poled controlled rectifiers.

14. A motor system as set forth in claim 13 wherein said shunt elements are disposed between the primary winding and the third secondary winding with the other secondary windings directly inductively coupled to the primary winding.

15. A motor system as set forth in claim 1 wherein the oppositely poled rectifiers are directly connected anode of one to cathode of the other and cathode of one to anode of the other.

16. A motor system as set forth in claim 14 wherein each pair of rectifiers they are directly connected anode of one to cathode of the other and cathode of one to anode of the other.