# US 10,374,500 B2 · Permanent magnet machine

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- Number: US 10,374,500 B2
- Document ID: US10374500B2
- Status: Granted
- Kind: B2
- Application number: 15/528,398
- Filed: 2016-03-31
- Published: 2017-11-16
- Granted: 2019-08-06
- Earliest claimed: 2015-04-09
- Assignees: The Switch Drive Systems Oy
- Applicants: The Switch Drive Systems Oy
- Inventors: Panu Kurronen; Markus Silventoinen; Jussi Puranen
- Web page: https://patentgrep.com/patent/US10374500B2

## CPC

- H02K 16/02: Machines with one stator and two {or more} rotors
- B63J 3/02: from propulsion power plant
- F01D 5/066: {Connecting means for joining rotor-discs or rotor-elements together, e.g. by a central bolt, by clamps}
- H02K 1/2753: the rotor consisting of magnets or groups of magnets arranged with alternating polarity
- H02K 1/278: Surface mounted magnets; Inset magnets
- H02K 1/28: Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures
- H02K 1/30: using intermediate parts, e.g. spiders
- H02K 21/029: {Vectorial combination of the fluxes generated by a plurality of field sections or of the voltages induced in a plurality of armature sections}
- B63H 23/24: electric {(dynamo-electric machines H02K)}
- B63J 2003/002: {by using electric power}
- F01D 5/3053: {by means of pins}
- H02K 2201/06: Magnetic cores, or permanent magnets characterised by their skew
- H02K 2213/09: Machines characterised by the presence of elements which are subject to variation, e.g. adjustable bearings, reconfigurable windings, variable pitch ventilators
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- B63J: AUXILIARIES ON VESSELS
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B63H: MARINE PROPULSION OR STEERING (propulsion of air-cushion vehicles B60V1/14; specially adapted for submarines, other than nuclear propulsion, B63G; specially adapted for torpedoes F42B19/00)

## Abstract

A rotor for a permanent magnet machine includes first and second axially successive rotor sections each including permanent magnets generating magnetic field having a pole pitch. The rotor includes a first coupling system for connecting the first rotor section to a shaft and a second coupling system for connecting the second rotor section to the shaft or to the first rotor section. The second rotor section is rotatable with respect to the first rotor section by an angle corresponding to the pole pitch in response to releasing the second coupling system so as to set the stator flux-linkages generated by the first and second rotor sections to be substantially zeroes. Thereafter, the permanent magnets do not substantially induce voltages on the stator windings even if the rotor is rotating during for example an internal fault of stator windings.

## Claims

### Claim 1

A rotor for a permanent magnet machine, the rotor comprising:
a first rotor section comprising first permanent magnets generating magnetic field having a pole pitch,
a second rotor section comprising second permanent magnets generating magnetic field having the same pole pitch, the first and second rotor sections being axially successive, and
a first coupling system for connecting the first rotor section to a shaft and a second coupling system for connecting the second rotor section to the shaft or to the first rotor section,
wherein the second rotor section is rotatable with respect to the first rotor section by an angle corresponding to the pole pitch in response to releasing the second coupling system so as to set magnetic flux-linkages generated by the first and second permanent magnets on stator windings of the permanent magnet machine to be substantially zeroes.

### Claim 2 (depends on 1)

The rotor according to claim 1, wherein the rotor further comprises at least one spring loaded locking device for locking the second rotor section with respect to the first rotor section in response to a situation in which the second rotor section has been rotated by the angle corresponding to the pole pitch with respect to the first rotor section.

### Claim 3 (depends on 1)

The rotor according to claim 1, wherein the second coupling system comprises one or more shear pins for connecting the first and second rotor sections to each other.

### Claim 4 (depends on 3)

The rotor according to claim 3, wherein a first end of each of the shear pins is shaped to be twistable with a tool and a second end of each of the shear pins is non-rotatably locked to one of the first and second rotor sections so as to make the shear pins breakable by twisting the first ends of the shear pins.

### Claim 5 (depends on 4)

The rotor according to claim 4, wherein the first end of each of the shear pins is provided with a bolt head.

### Claim 6 (depends on 1)

The rotor according to claim 1, wherein the second coupling system comprises one or more bolts for connecting the first and second rotor sections to each other.

### Claim 7

A permanent magnet machine comprising:
a stator, and
a rotor,
wherein the rotor comprises:
a first rotor section comprising first permanent magnets generating magnetic field having a pole pitch,
a second rotor section comprising second permanent magnets generating magnetic field having the same pole pitch, the first and second rotor sections being axially successive, and
a first coupling system for connecting the first rotor section to a shaft and a second coupling system for connecting the second rotor section to the shaft or to the first rotor section,
wherein the second rotor section is rotatable with respect to the first rotor section by an angle corresponding to the pole pitch in response to releasing the second coupling system so as to set magnetic flux-linkages generated by the first and second permanent magnets on stator windings of the permanent magnet machine to be substantially zeroes.

### Claim 8 (depends on 7)

The permanent magnet machine according to claim 7, wherein the stator comprises star-connected phase-windings and the permanent magnet machine further comprises a switch between each of the phase-windings and a star point of the star-connected phase-windings.

### Claim 9 (depends on 7)

The permanent magnet machine according to claim 7, wherein the permanent magnet machine further comprises a switch at each of electrical terminals for connecting the permanent magnet machine to an external electrical system.

### Claim 10

A method for deactivating a permanent magnet machine whose rotor comprises: axially successive first and second rotor sections, a first coupling system for connecting the first rotor section to a shaft, and a second coupling system for connecting the second rotor section to the shaft or to the first rotor section, the method comprising:
releasing the second coupling system so as to make the first and second rotor sections rotatable with respect to each other, and
rotating the first and second rotor sections with respect to each other by an angle corresponding to a pole pitch of magnetic fields generated by permanent magnets of the first and second rotor sections so as to set magnetic flux-linkages generated by the first and second rotor sections on stator windings of the permanent magnet machine to be substantially zeroes.

### Claim 11 (depends on 2)

The rotor according to claim 2, wherein the second coupling system comprises one or more shear pins for connecting the first and second rotor sections to each other.

### Claim 12 (depends on 11)

The rotor according to claim 11, wherein a first end of each of the shear pins is shaped to be twistable with a tool and a second end of each of the shear pins is non-rotatably locked to one of the first and second rotor sections so as to make the shear pins breakable by twisting the first ends of the shear pins.

### Claim 13 (depends on 12)

The rotor according to claim 12, wherein the first end of each of the shear pins is provided with a bolt head.

### Claim 14 (depends on 2)

The rotor according to claim 2, wherein the second coupling system comprises one or more bolts for connecting the first and second rotor sections to each other.

### Claim 15 (depends on 8)

The permanent magnet machine according to claim 8, wherein the permanent magnet machine further comprises a switch at each of electrical terminals for connecting the permanent magnet machine to an external electrical system.