Assembly Comprising a Three-Phase Machine and a Frequency Converter

• US 20090039816A1
• Filed: 04/05/2006
• Published: 02/12/2009
• Est. Priority Date: 04/13/2005
• Status: Active Grant

• Current Assignee: AB SKF
• Original Assignee: AB SKF
• Inventors: Buschbeck, Frank, Groeschl, Martin, Jagenbrein, Andreas, Preisinger, Gerwin
• Granted Patent: US 7,948,206 B2
• Time in Patent Office: Days
• US Class Current: 318/494
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: H02P 29/02 Providing protection against overload without automatic interruption of supply protection against faults of stepper motors H02P8/36

Abstract

A system is provided that furnishes expert procedural guidance based upon patient-specific data gained from surgical instruments incorporating sensors on the instrument'"'"'s working surface, one or more reference sensors placed about the patient, sensors implanted before, during or after the procedure, the patient'"'"'s personal medical history, and patient status monitoring equipment. Embodiments include a system having a surgical instrument with a sensor for generating a signal indicative of a property of a subject tissue of the patient, which signal is converted into a current dataset and stored. A processor compares the current dataset with other previously stored datasets, and uses the comparison to assess a physical condition of the subject tissue and/or to guide a procedure being performed on the tissue.

Claims

1. Arrangement with a three-phase a.c. machine and a frequency converter comprising:

the three-phase a.c. machine, including a stator and a rotor, whereby at least the three electric circuits of the stator and/or the rotor for the three three-phase a.c. phases are insulated from one another in operation with one separate connecting point of the stator and/or the rotor each corresponding to the connecting point of the frequency converter, and

the frequency converter being a midpoint-grounded d.c. intermediate circuit, in such a way that for each electric circuit, an electric voltage or current that is symmetrical relative to the ground potential can be output between the two corresponding connecting points.

2. Arrangement according to claim 1, whereby the rotor is mounted to rotate against the stator via at least one bearing.

3. Arrangement according to claim 2, whereby the bearing comprises a roller bearing.

4. Arrangement according to claim 3, whereby the roller bearing is made essentially of roller bearing steel.

5. Arrangement according to claim 3, whereby the roller bearing comprises a roller, in particular cylinder rollers, cone rollers and/or spherical roller bearings and/or ball bearings.

6. Arrangement according to claim 2, whereby the bearing is made as a bearing that is insulated against flowing current.

7. Arrangement according to claim 1, whereby each of the electric circuits comprises a three-phase a.c. machine winding.

8. Arrangement according to claim 1, whereby the frequency converter is designed to tap-off the balanced-to-ground voltage or current between two d.c. voltage potentials of opposite polarity but of equal value.

9. Arrangement according to claim 1, whereby the balanced-to-ground voltage or current is modulated by pulse width.

10. Arrangement according to claim 1, whereby the frequency converter comprises one pole-changer circuit for each electric circuit.

11. Arrangement according to claim 1, whereby the three-phase a.c. machine is designed such that for each electric circuit, a stray capacitance is divided essentially symmetrically relative to a housing of the three-phase a.c. machine relative to a midpoint of the electric circuit between the two connecting points of the electric circuit.

12. Arrangement according to claim 1, whereby the three-phase a.c. machine is designed such that for each electric circuit, a stray capacitance relative to a shaft of the three-phase a.c. machine is divided essentially symmetrically between the two connecting points of the electric circuit relative to a midpoint of the electric circuit.

13. Arrangement according to claim 1, whereby the three-phase a.c. machine can be connected to the frequency converter via an at least six-core connecting line.

14. Arrangement according to claim 13, whereby the connecting line comprises at least a seventh core as a protective ground connection to connect a housing of the three-phase a.c. machine to a grounding point on the frequency converter.

15. Arrangement according to claim 13, whereby the connecting line is unshielded.