GB2059686A - Brush for electrical machine - Google Patents

Brush for electrical machine Download PDF

Info

Publication number
GB2059686A
GB2059686A GB7924548A GB7924548A GB2059686A GB 2059686 A GB2059686 A GB 2059686A GB 7924548 A GB7924548 A GB 7924548A GB 7924548 A GB7924548 A GB 7924548A GB 2059686 A GB2059686 A GB 2059686A
Authority
GB
United Kingdom
Prior art keywords
brush
insulating layer
layer
split
layers
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
Application number
GB7924548A
Other versions
GB2059686B (en
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.)
Morganite Electrical Carbon Ltd
Original Assignee
Morganite Electrical Carbon 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 Morganite Electrical Carbon Ltd filed Critical Morganite Electrical Carbon Ltd
Priority to GB7924548A priority Critical patent/GB2059686B/en
Publication of GB2059686A publication Critical patent/GB2059686A/en
Application granted granted Critical
Publication of GB2059686B publication Critical patent/GB2059686B/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/02—Details for dynamo electric machines
    • H01R39/18—Contacts for co-operation with commutator or slip-ring, e.g. contact brush
    • H01R39/24—Laminated contacts; Wire contacts, e.g. metallic brush, carbon fibres

Landscapes

  • Motor Or Generator Current Collectors (AREA)

Abstract

A split brush for an electric machine has its commutating and other operating characteristics improved by having relatively-movable conductive brush layers 10, 11 spaced apart by insulation 13, e.g. siliconised paper, which can be bonded to the part 11 along part or all of its length. A rubber pad 16 may be provided on the top. <IMAGE>

Description

SPECIFICATION Brush for electrical machine The invention relates to brushes for electric machines, which brushes are of the split type, that is of the type comprising a number of unbonded conductive layers.
According to the invention, conductive layers of a split brush are spaced apart by an insulating layer.
Conveniently, the insulating layer is of a paper material, which may be impregnated or otherwise treated with a silicone substance.
The insulating layer may be bonded to one of the brush layers it separates, either over the whole surface or over a limited area adjacent the top of that brush layer. Also if desired the insulating layer may be folded over onto the top surface of one of the brush layers it separates, and in such a construction the insulating pad of rubber or the like sometimes provided on the top of brushes may overlie the folded over portion of the insulating layer.
The provision of such an insulating layer has for its purpose to improve the commutating characteristics of the brush by increasing the resistance to commutation currents so improving brush and electric machine performance, and to improve brush stability by damping segmental stick/slip action.
Also as compared with a sandwich type brush wherein the brush layers are bonded together through an insulating layer, the brush of this invention has a reduced abrasive effect, and is more easily manufactured since bonding becomes unnecessary.
The accompanying drawing shows one form of brush of this invention. In the drawing Figure 1 is a side elevation of the brush, Figure 2 is a section on the line 2-2 of Fig.
1, and Figure 3 is a diagram.
In the drawing, the "carbon" brush illustrated has two conductive layers 10, 11 of which the contact surface is indicated by arrow 12.
The two layers 10, 11 are separated by an insulating layer 1 3 of siliconised paper, for instance the paper product sold under the trade name "Nomex".
The insulating layer is shown as having a portion 1 3a folded over to lie on the top surface of layer 11 below a resilient pad 1 6 of rubber or rubber/Tufnal (RTM) material.
The insulating layer 1 3 is either bonded over the whole length of the layer 11 or over a limited area 14 as indicated by bracket in Fig. 1 and dot and dash shading in Fig. 2.
The brush layer 10 is free to move relatively to the layer 11.
In use the resistance to commutation current is increased since the current must flow through contact resistance rc1, brush resistance rb,, flexible resistances rl1, rl2, brush resistance rb2 and contact resistance rc2.
1. A split brush for an electric machine wherein the conductive brush layers are spaced apart by an insulating layer.
2. A split brush according to claim 1, wherein the insulating layer is a paper.
3. A split brush according to claim 2, wherein the paper material is treated with a silicone substance.
4. A split brush according to any of claims 1 to 3, wherein the insulating layer is bonded to one of the conductive layers it separates over the whole length of that layer or only adjacent the top of that layer.
5. A split brush according to any of claims 1 to 4, wherein the insulating layer is folded over on to the top of one of the conductive layers it separates.
6. A split brush constructed and arranged to function substantially as hereinbefore described with reference to the drawing.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Brush for electrical machine The invention relates to brushes for electric machines, which brushes are of the split type, that is of the type comprising a number of unbonded conductive layers. According to the invention, conductive layers of a split brush are spaced apart by an insulating layer. Conveniently, the insulating layer is of a paper material, which may be impregnated or otherwise treated with a silicone substance. The insulating layer may be bonded to one of the brush layers it separates, either over the whole surface or over a limited area adjacent the top of that brush layer. Also if desired the insulating layer may be folded over onto the top surface of one of the brush layers it separates, and in such a construction the insulating pad of rubber or the like sometimes provided on the top of brushes may overlie the folded over portion of the insulating layer. The provision of such an insulating layer has for its purpose to improve the commutating characteristics of the brush by increasing the resistance to commutation currents so improving brush and electric machine performance, and to improve brush stability by damping segmental stick/slip action. Also as compared with a sandwich type brush wherein the brush layers are bonded together through an insulating layer, the brush of this invention has a reduced abrasive effect, and is more easily manufactured since bonding becomes unnecessary. The accompanying drawing shows one form of brush of this invention. In the drawing Figure 1 is a side elevation of the brush, Figure 2 is a section on the line 2-2 of Fig. 1, and Figure 3 is a diagram. In the drawing, the "carbon" brush illustrated has two conductive layers 10, 11 of which the contact surface is indicated by arrow 12. The two layers 10, 11 are separated by an insulating layer 1 3 of siliconised paper, for instance the paper product sold under the trade name "Nomex". The insulating layer is shown as having a portion 1 3a folded over to lie on the top surface of layer 11 below a resilient pad 1 6 of rubber or rubber/Tufnal (RTM) material. The insulating layer 1 3 is either bonded over the whole length of the layer 11 or over a limited area 14 as indicated by bracket in Fig. 1 and dot and dash shading in Fig. 2. The brush layer 10 is free to move relatively to the layer 11. In use the resistance to commutation current is increased since the current must flow through contact resistance rc1, brush resistance rb,, flexible resistances rl1, rl2, brush resistance rb2 and contact resistance rc2. CLAIMS
1. A split brush for an electric machine wherein the conductive brush layers are spaced apart by an insulating layer.
2. A split brush according to claim 1, wherein the insulating layer is a paper.
3. A split brush according to claim 2, wherein the paper material is treated with a silicone substance.
4. A split brush according to any of claims 1 to 3, wherein the insulating layer is bonded to one of the conductive layers it separates over the whole length of that layer or only adjacent the top of that layer.
5. A split brush according to any of claims 1 to 4, wherein the insulating layer is folded over on to the top of one of the conductive layers it separates.
6. A split brush constructed and arranged to function substantially as hereinbefore described with reference to the drawing.
GB7924548A 1979-07-13 1979-07-13 Brush for electrical machine Expired GB2059686B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7924548A GB2059686B (en) 1979-07-13 1979-07-13 Brush for electrical machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7924548A GB2059686B (en) 1979-07-13 1979-07-13 Brush for electrical machine

Publications (2)

Publication Number Publication Date
GB2059686A true GB2059686A (en) 1981-04-23
GB2059686B GB2059686B (en) 1983-08-17

Family

ID=10506503

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7924548A Expired GB2059686B (en) 1979-07-13 1979-07-13 Brush for electrical machine

Country Status (1)

Country Link
GB (1) GB2059686B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021107460B3 (en) 2021-03-25 2022-09-29 Audi Aktiengesellschaft Predictive brush control for separately excited electric motors

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021107460B3 (en) 2021-03-25 2022-09-29 Audi Aktiengesellschaft Predictive brush control for separately excited electric motors

Also Published As

Publication number Publication date
GB2059686B (en) 1983-08-17

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee