TOOLS & DEVICES

MAINTENANCE TOOLS & MEASURING DEVICES

FOR MAINTENANCE OF
ELECTRICAL MACHINES
Preventive maintenance
of slip rings and commutators

PREVENTION

ECONOMY

SECURITY

Regular controls reduce

the frequency of
maintenance operations
 2
Measuring devices
For over 120 years, Mersen has been developing carbon brush grades and manufacturing carbon brushes for electrical
machines. Our expertise of motors and our experience of industrial maintenance enables us to offer you a global range
of solutions adapted to your requirements:
• Brush-holders, carbon brushes and slip rings
• A team specialized in on site motor technical assistance (in-situ machining operations)
• A whole range of tools selected for maintenance of slip rings and commutators
• A Customer Technical Assistance Service
• Training in maintenance of electrical machines and in knowledge of commutation
The devices, tools and accessories displayed in this catalogue were not only tested in the laboratory, but above all on
site. Our experts selected them for your full and entire satisfaction.

CL-PROFILER PROFILOMETER
It is necessary to check regularly that the deformation of slip rings and commutators (out of round) remains within acceptable
limits. The CL-Profiler, easy to use in the field, will give you a very clear image of this deformation, and will enable you to follow
the evolution of the wear of your electrical rotating machinery.

CL-Profiler Profilometer

Reference Description
90328N CL-Profiler without PC
90324N ViRoTi probe
90355N 2.5 mm ruby tip
90340N 5 mm ruby tip
90341N 8 mm ruby tip
90358N 18 mm ceramic tip
90356N 10 mm roller tip
90360N Analysis software

DIAMETER
The DiaMeter will enable you to measure the diameter of slip ring assemblies, commutators and rolling stock wheels prior to any
possible machining. This is a portable tool, adaptable to the size of your commutators and/or wheels. It uses the same probe as
the CL-Profiler and a specific extension of its software.

DiaMeter

Reference Description
90372N Tool for 50 to 350 mm diameters
90373N Tool for 300 to 950 mm diameters
90374N Customized DiaMeter tool for 50 to 350 mm diameters
90324N ViRoTi probe

COMMUTATION INDICATOR
Incorrect commutation can generate sparking which can damage your slip rings and commutators. The Commutation Indicator is
the solution to accurately measure the spark intensity on DC electrical machines. It is sold with 2 sensors, 2 isolating contacts for
sensors and 1 magnetic stand.

Commutation Indicator

Reference Description
90375N Commutation Indicator and its accessories in their protective carrying case
 3
Measuring devices

DYNAMOMETER
Carbon brush pressure determines electrical and mechanical losses, commutation quality, current distribution between the
carbon brushes, brush and commutator wear, and therefore influences the machine’s whole performance. It is important to make
periodic pressure measurements on the brush-holder springs and to check spring pressure between brushes of the same polarity
on commutators and between brushes on the same slip ring. Pressure differences cause unequal current distribution and
therefore unequal brush wear, increasing the frequency of maintenance operations. Mersen can refurbish or change your brush-
holders, and propose you a whole range pressure systems.

Electronic dynamometer

Reference Description
90349N Dynamometer 1,000 measurements
90351N Brown probe - 0.5 to 10 N A = 6.5 mm B = 48 mm C = 8 mm
90350N Red probe - 10 to 20 N A = 7.5 mm B = 85 mm C = 10 mm
90352N Blue probe - 20 to 60 N A = 9.5 mm B = 95 mm C = 12 mm

ROUGHNESS METER
Optimum carbon brush performance depends on the surface roughness of slip rings or commutators being maintained within
recommended values.

M300C roughness meter

Reference Description
90357N M300C roughness meter with lengthwise drive unit
90363N M300C roughness meter without drive unit
90361N Transversal drive unit
90362N Additional probe

ALARM BOX
Commutators and slip rings are likely to get damaged by worn out carbon brushes. The alarm carbon brush includes, in addition
to its shunt, a thin copper braid, entirely protected by an insulated sleeve; it is located deeper than the carbon brush tamping.
When the carbon brush is worn, the alarm shunt comes into contact with the commutator / slip ring (without causing any damage
to the sliding surface), the short-circuit triggers the warning light.

Alarm box

Reference Description
90702N Brush wear detection alarm box

STROBOSCOPE
On badly deformed slip rings or commutators causing important brush vibrations, out roundness can by easily located and
identified with our stroboscope.

Stroboscope

Reference Description
90313N Digital stroboscope
90315N Spare lamp
 4
Tools for maintenance of electrical machines

GRINDING STONES
The commutator or the slip rings of an electrical machine must have a proper roughness to give the carbon brushes an adequate
seating base and enable them to ensure a good current transmission.
To achieve this proper roughness, the commutator or the slip ring has to be «ground» after machining with a medium grinding
stone such as P/N 90623N. If you wish to work without dismantling the machine, rather use a grinding stone with a handle. P/N
90602N is ideal for motors up to 15 kW, while P/N 90651N is suitable for motors up to 150 kW. For bigger motors, use P/N
90612N or 90607N, which are larger.
Our grinding stones have four different grain sizes, each adapted to the work to be done. These stones are suitable for copper,
bronze and steel.
• Coarse grinding stone (C): with big grains, it does not erode much and is good for removing large quantities of material.
• Medium grinding stone (M): with an average grain size which is suitable for removing minor defects, it is recommended for
finishing any commutator or slip ring machining. Its grain size is designed for achieving the right roughness for a good brush
seating base and film deposit.
• Finish grinding stone (F): with fine grains suitable for commutator cleaning or for achieving the right roughness on certain
types of soft copper commutator.
• Polish grinding stone (P): with very fine grains

Two-grade combination grinding stones

Reference Dimensions in mm Grain

90608N 50x25x200 C/M
90607N 50x25x200 M/F

Two-grade combination grinding stone Grinding stones with three-position adjustable handle and thrust knob

Reference Dimensions in mm Grain

90612N 50x40x50 M
90611N 50x40x50 F

Single-handle grinding stones. The handle is mounted lengthwise.

Grinding stone with adjustable handle Reference Dimensions in mm Grain

90613N 130x80x50 C
90614N 130x80x50 M

Double-handle grinding stones. The two handles are mounted crosswise.

Reference Dimensions in mm Grain

90618N 100x200x80 C
Single-handle grinding stone 90619N 100x200x80 M

Tower-type grinding stones for commutators and slip rings

Reference Dimensions in mm Grain

90635N 20x20x80 C
90637N 20x20x80 M
Double-handle grinding stone 90636N 20x20x80 F
90621N 25x40x160 C
90623N 25x40x160 M
90622N 25x40x160 F
90629N 25x40x280 C
90631N 25x40x280 F
90627N 50x50x200 C
90625N 50x50x200 M
90626N 50x50x200 F
Tower-type grinding stone 90640N 30x30x200 C
90641N 30x30x200 M
 5
Tools for maintenance of electrical machines
Straight-handle grinding stones (two different grades)

Reference Dimensions in mm Grain

90601N 10x12x20 M and F
90602N 10x12x20 F and P
90603N 10x12x20 M and C
Straight-handle grinding stone

Pencil-type grinding stones

Reference Dimensions in mm Grain

90604N 10x15x150 C
90606N 10x15x150 M
90605N 10x15x150 F

Commutator polisher with curved plastic handle

Pencil-type grinding stone

Reference Dimensions in mm Grain

90651N 8x22x17,5 F/P

Brush seaters

Meant for seating carbon brushes, this material does not wear metal much. It must not
be used intensively, unless with a dust collection device.
Reference Dimensions in mm Grain
Commutator polisher
90661N 6x6x120 M (Medium)
90662N 6x12x120 M
90663N 10x10x120 H (Hard/Dur)
90664N 10x10x120 M
90665N 12x20x120 H
90666N 15x30x120 H
90667N 15x30x120 M
90668N 15x30x120 S (Tendre/Soft)
90669N 50x25x120 S
Brush seater
90672N 80x50x150 S

Slotting files

Files designed to chamfer bar edges.

Reference Description
90553N Slotting file without handle

Slotting files
Slotter

Hand tool meant for mica undercutting, burr removal and bar edge chamfering. This steel
tool provides a “V” and a “U” cutting edges.
Reference Description
90554N Three-side slotter with blade
90555N Spare blade for 90554N

Slotter
Flexible abrasives

Fine-grain insulating material, specifically meant for cleaning commutator or slip ring skin
of small machines. It cannot be used as a grinding tool.
Reference Description
90652N 10x12x120
90653N 10x20x120
90655N 15x25x120
90654N 25x50x120
Flexible abrasive
90658N 20x30x200
 6
Tools for maintenance of electrical machines

PORTABLE MICA UNDERCUTTER

Portable mica undercutter

• Compressed air angle grinder, with built-in sound-insulating features and

adjustable air outlet. Very handy with depth adjustment and protective cap for
offhand grinding up to 60 N. Supplied with a spanner set.
• Power: 75 W
• Weight: 180 g
• Couplings: R 1/8
• Air consumption: 0.2 m3/min
• No-load speed: 70,000 rpm
Portable mica undercutter • Supplied without air pack nor connector piece
• Used cutters: Diameter 19 mm and diameter 22 mm diamond discs
Reference Description
90570N Mica undercutter for 19 mm and 22 mm diameter diamond discs

19 mm diameter diamond discs

These diamond discs are adapted to our 90570N portable mica undercutter.
Reference Thickness
90571N 0.5 mm
90572N 0.6 mm
Ø19 mm diamond disc 90573N 0.8 mm
90574N 1 mm

22 mm diameter diamond discs

These diamond discs are adapted to our 90570N portable mica undercutter.
Reference Thickness
90575N 0.5 mm
90576N 0.6 mm
Ø22 mm diamond disc 90577N 0.8 mm
90578N 1 mm

Abrasive strip

This abrasive strip is particularly adapted to on site carbon brush seating. It ensures
a quick and efficient work, with no abrasive grain erosion.
Reference Description
90206N Grain 80 abrasive strip, width 9 cm x 10 m
Abrasive strip

PATINA WAX

Patina wax

Applied to the commutator after a grinding operation, patina wax contributes to a

quick film deposit.

Reference Description
Patina wax
90202N Wax stick
 7
Tools for maintenance of electrical machines

TOOLING KITS

Maintenance kit

This kit includes a selection of tools meant for maintenance and repair specialists in
charge of slip rings, commutators and carbon brushes.

Reference N° Description
90201N Complete kit including following tools:
90285N 1 Insulating probe
90286N 2 Facom LED lamp
90287N 3 Set of gauges
90288N 4 Graduated rule
90554N 5 Slotter
90651N 6 Commutator polisher with curved plastic handle
Maintenance kit 90668N 7 Brush seater

Maintenance tool case

It includes a set of grinding stones and slotters for the preparation of all types of
commutators and slip rings.
Reference N° Description
90205N Complete carrying case including folllowing tools:
90607N 1 Two-grade combination grinding stone
90655N 2 Flexible abrasive
90665N 3 Brush seater
90605N 4 Pencil-type grinding stone
90623N 5 Tower-type grinding stone
90553N 6 Slotting file
90554N 7 Slotter
90601N 8 Straight-handle grinding stones
90651N 9 Commutator polisher with curved plastic handle
Maintenance tool case 90612N 10 Adjustable handle grinding stone
90285N 11 Insulating probe
90287N 12 Set of gauges

 Do not hesitate and contact us to find out

more about our other maintenance tools and
measuring devices. Mersen can also provide
you with various types of technical training
and motor maintenance services.
 Ask for our « Maintenance of carbon
brushes, brush-holders, commutators and slip
rings » guide
 AE-Services/tools-catalogue-EN-1502
Tools and Devices for maintenance of electrical
machines
Mersen Services, servicing your electrical rotating machinery
For any technical expertise, maintenance or training, Mersen experts offer their extensive knowledge,
years of experience and global reach, linked with a reactive proximity service.

 On-site service calls throughout the world

 Commutation expertise
 Measurements and diagnostics
 Support services on a daily basis
 Phone technical assistance
 Technical literature on line of our site www.mersen.com or on request (infos.amiens@mersen.com)

Mersen provides training courses for maintenance of electric motors. For over 25 years, more than 3,000
technicians have been undergone training, either at our facility of theirs.

 Diagnostics
 In situ commutator, slip ring and brush-holder refurbishment:
• Surface re-conditioning
• Mica undercutting (commutators)
• Bar edge chamfering (commutators)
• Helical groove edge chamfering (slip rings)
• Out-of-round machining
• Carbon brush pressure measurement
• Proposal of suitable carbon brush grade
• Redesign of the complete carbon brush, brush-holder and commutator / slip ring system
• Installation of features to improve the performance of your machines (remote carbon brush wear monitoring,
dust extraction solutions...)
• Retrofit solutions
 Support services on a daily basis

A GLOBAL PLAYER
Mersen is a Global Expert in electrical specialties and graphite-based materials.

The specifications or data contained in present catalogue are only given for information and do not create any undertakings whatsoever. Any copy, reproduction or
translation, either partially or fully, of these information is subject to the Mersen’s prior written consent.
In addition, due to the continuing improvement of techniques and change of applicable standards, Mersen is entitled to modify at any time the characteristics and
specifications of its products as described in present catalogue.

Contact: infos.amiens@mersen.com / 03 22 54 46 62
www.mersen.com