GB2143995A - Position-pick-off devices - Google Patents

Position-pick-off devices Download PDF

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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
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United Kingdom
Prior art keywords
output
secondary windings
instantaneous
pair
pole
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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
Application number
GB08320168A
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GB8320168D0 (en
GB2143995B (en
Inventor
John Michael Masterman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dowty Fuel Systems Ltd
Original Assignee
Dowty Fuel Systems Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Dowty Fuel Systems Ltd filed Critical Dowty Fuel Systems Ltd
Priority to GB08320168A priority Critical patent/GB2143995B/en
Publication of GB8320168D0 publication Critical patent/GB8320168D0/en
Publication of GB2143995A publication Critical patent/GB2143995A/en
Application granted granted Critical
Publication of GB2143995B publication Critical patent/GB2143995B/en
Expired legal-status Critical Current

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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

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  • 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)

**WARNING** start of CLMS field may overlap end of DESC **. 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. CLAIMS
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.
GB08320168A 1983-07-26 1983-07-26 Position-pick-off devices Expired GB2143995B (en)

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

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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)

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GB (1) GB2143995B (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1295657A (en) * 1968-12-17 1972-11-08

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1295657A (en) * 1968-12-17 1972-11-08

Also Published As

Publication number Publication date
GB8320168D0 (en) 1983-08-24
GB2143995B (en) 1986-10-29

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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