GB2143995A - Position-pick-off devices - Google Patents
Position-pick-off devices Download PDFInfo
- Publication number
- GB2143995A GB2143995A GB08320168A GB8320168A GB2143995A GB 2143995 A GB2143995 A GB 2143995A GB 08320168 A GB08320168 A GB 08320168A GB 8320168 A GB8320168 A GB 8320168A GB 2143995 A GB2143995 A GB 2143995A
- Authority
- GB
- United Kingdom
- Prior art keywords
- output
- secondary windings
- instantaneous
- pair
- pole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000004804 winding Methods 0.000 claims abstract description 45
- 230000005284 excitation Effects 0.000 claims abstract description 5
- 230000001419 dependent effect Effects 0.000 claims description 2
- 230000005611 electricity Effects 0.000 claims description 2
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
- H02K29/06—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices
- H02K29/12—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices using detecting coils using the machine windings as detecting coil
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
An alternating-current rotary position-pick-off device has a four pole stator (1), each pole piece (2,3,4,5) having a primary excitation winding (6,7,8,9). One pair of opposed pole pieces (2,4) has a first pair of secondary windings (11,12). The other pair of opposed pole pieces (3,5) has a second pair of secondary windings (14,15). Means, such as two phase- sensitive rectifiers (not shown), are respectively associated with the two pairs of secondary windings to compare the instantaneous induced voltages in the secondary windings. An output signal is provided which is determined by the instantaneous position, with respect to the stator, of a semi-circular rotor (17). <IMAGE>
Description
SPECIFICATION
Position-pick-off devices
This invention relates to rotary position-pickoff devices.
According to this invention an alternatingcurrent rotary position-pick-off device comprises
(i) a four pole stator,
(ii) a primary excitation winding on each pole which provide alternate polarity of the pole pieces around the stator when energised from an alternating current source,
(iii) A first pair of secondary windings, one on one pole piece and one on the opposite pole piece,
(iv) a second pair of secondary windings, one on one of the remaining pole pieces and the other on the opposite pole piece,
(v) a semi-circular rotor mounted for rotation with respect to the pole pieces, and
(vi) means for comparing the instantaneous induced voltages in the secondary windings to provide an output signal determined by the instantaneous position of the rotor with respct to the stator.
The means for comparing the instantaneous induced voltages may include a demodulator, e.g. a phase-sensitive rectifier, for the voltages induced in the first pair of secondary windings and another demodulator, e.g. another phasesensitive rectifier, for the voltages induced in the second pair of secondary windings. The demodulator outputs from the demodulator may be compared by dividing the output having the smaller magnitude by the output having the larger magnitude to produce a resultant output. From that, and from an examination of the polarity of the individual demodulator outputs, which will determine the quadrant in which the rotor is located, the instantaneous position can be determined e.g.
by means of a table stored in the memory of a digital controller with which the unit is operating.
A rotary position-pick-off device in accordance with one embodiment of the invention is shown in the accompanying drawing of which
Figure 1 is a schematic arrangement of the device and
Figure 2 shows the demodulated outputs from the device.
Referring to the drawings, the device comprises a laminated stator 1 having. four pole pieces 2, 3, 4 and 5. Each pole piece has a primary winding 6, 7, 8 and 9, connected to a source of electricity 10.
The primary windings are so connected that opposed pole pieces 2 and 4 have one polarity and opposed pieces 3 and 5 have the opposite polarity.
A secondary winding 11 on pole piece 2 is connected in opposition with a secondary winding 1 2 on the opposite pole piece 4 and are connected to output leads 1 3. Thus, when the voltages induced in them are equal, the resultant output at the leads 1 3 is zero.
A secondary winding 1 4 on pole piece 3 is connected in opposition with a secondary winding 1 5 on the opposite ppole piece 5 and are connected to output leads 1 6. Thus, when the voltages induced in them are equal, the resultant output at the leads 1 6 is zero.
A semi-circular laminated rotor 1 7 is mounted for rotation with respect to the pole pieces.
The output leads 1 3 are connected to a phase-sensitive rectifier (not shown) and the output leads 1 6 are connected to another phase-sensitive rectifier (not shown).
The induced voltages in the secondary windings taken out by way of output leads 1 3 and 1 6 vary with the position of the rotor as shown in Fig. 2. The demodulated output from one pair of secondary windings (11 and 12) is shown at A, and the demodulated output from the other pair of secondary windings (14 and 15) is shown at B. These two demodulated outputs are compared by
(i) dividing the instantaneous output having the smaller amplitude by the instantaneous output having the larger amplitude, and
(ii) by considering the polarity of the individual outputs. This produces a resultant instantaneous output signal shown at C.
The resultant instantaneous output signal shown at C is dependent on the instantaneous position of the rotor with respect to the stator and the precise instantaneous position at any instant can readily be determined by continuously applying the output signals to a computer in whose memory there is an appropriate programme.
1. An alternating-current rotary positionpick-off device comprising:
(i) a four pole stator,
(ii) a primary excitation winding on each pole which provide alternate polarity of the pole pieces around the stator when energised from an alternating current source,
(iii) a first pair of secondary windings, one on one pole piece and one on the opposite pole piece,
(iv) a second pair of secondary windings, one on one of the remaining pole pieces and the other on the opposite pole piece,
(v) a semi-circular rotor mounted for rotation with respect to the pole pieces, and
(vi) means for comparing the instantaneous induced voltages in the secondary windings to provide an output signal determined by the instantaneous position of the rotor with respect to the stator.
2. An alternating-current rotary positionpick-off device as claimed in Claim 1 in which the means for comparing the instantaneous
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (4)
1. An alternating-current rotary positionpick-off device comprising:
(i) a four pole stator,
(ii) a primary excitation winding on each pole which provide alternate polarity of the pole pieces around the stator when energised from an alternating current source,
(iii) a first pair of secondary windings, one on one pole piece and one on the opposite pole piece,
(iv) a second pair of secondary windings, one on one of the remaining pole pieces and the other on the opposite pole piece,
(v) a semi-circular rotor mounted for rotation with respect to the pole pieces, and
(vi) means for comparing the instantaneous induced voltages in the secondary windings to provide an output signal determined by the instantaneous position of the rotor with respect to the stator.
2. An alternating-current rotary positionpick-off device as claimed in Claim 1 in which the means for comparing the instantaneous induced voltages includes a demodulator for the voltages induced in the first pair of secondary windings and another demodulator for the voltages induced in the second pair of secondary windings.
3. An alternating-current rotary positionpick-off device as claimed in Claim 2 in which each demodulator is a phase-sensitive rectifier.
4. An alternating-current rotary positionpick off device substantially as hereinbefore described and with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08320168A GB2143995B (en) | 1983-07-26 | 1983-07-26 | Position-pick-off devices |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08320168A GB2143995B (en) | 1983-07-26 | 1983-07-26 | Position-pick-off devices |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8320168D0 GB8320168D0 (en) | 1983-08-24 |
| GB2143995A true GB2143995A (en) | 1985-02-20 |
| GB2143995B GB2143995B (en) | 1986-10-29 |
Family
ID=10546327
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08320168A Expired GB2143995B (en) | 1983-07-26 | 1983-07-26 | Position-pick-off devices |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2143995B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1295657A (en) * | 1968-12-17 | 1972-11-08 |
-
1983
- 1983-07-26 GB GB08320168A patent/GB2143995B/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1295657A (en) * | 1968-12-17 | 1972-11-08 |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2143995B (en) | 1986-10-29 |
| GB8320168D0 (en) | 1983-08-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19940726 |