Mechanical Technology July 2016

Mechanical Technology — July 2016

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Power transmission, bearings, bushes and seals

⎪

OEMS rely

on rotor balancing capacity

eading local repairer of rotating electri-

cal equipment, Marthinusen & Coutts

says its in-house ability to precision

balance rotors to a high accuracy improves

vibration levels, thereby increasing reliabil-

ity while reducing customer maintenance

costs.

Marthinusen Coutts, a division of

Actom, operates the third largest high-

speed dynamic balancing machine in

sub-Saharan Africa. Mike Chamberlain,

marketing executive at Marthinusen &

Coutts, says the advanced machine is in

constant use with local OEMs benefitting

tremendously by having access to an in-

dependent balancing service of this quality

and capacity.

The 32 t Schenck HM7 U/S balanc-

ing machine is located at Marthinusen &

Coutts’ 9 500 m² high tech workshop in

Cleveland, near Johannesburg. The HM7

U/S balancing machine is 9 000 mm long

and has a measuring range between 100

and 5 000 rpm. It has a journal size of

400 mm and a swing of 2 400 mm.

It is fitted with a CAB 920 H measur-

ing instrument with a vector display.

Its state-of-the-art technology makes

changeovers to new rotor types quick and

straightforward.

“The machine facilitates the balancing

of all larger high speed rotors dynamically

at full operating speed and sometimes,

depending on the design of the rotor and

customer requirements, at 10% over-

speed,” Chamberlain says.

All rotors are balanced in-house which

speeds up the process and reduces costs

with the service being available to external

customers on a first come, first served ba-

sis. The machine is operated by one of the

country’s top balancing machine experts

in line with international best practice with

industry standard balancing certificates be-

ing issued for each completed rotor.

The largest rotor balanced at full speed

to date was a 15-ton 4-pole rotor for a

28 MW compressor motor required by a

leading local steel producer.

Marthinusen & Coutts provides this

crucial service to the power generation

industry, balancing both high pressure and

low-pressure turbines. The division has also

partially (low speed) balanced generator

rotors up to 60 MW where the rotors are

subsequently trim-balanced at full speed

on site, once the rotor has been installed.

“It goes without saying that the service

has obvious time and expense advantages

for those making use of it,” Chamberlain

concludes.

Above:

Thome and Schwind high quality fasteners range

from standard types to stainless steel and special nickel

alloy materials for use in extreme conditions.

Right:

Huck

Bobtail lockbolts offer up to 10 times the fatigue strength

of conventional nuts and bolts and are suitable for

heavy duty applications where ultimate vibra-

tion resistance is critical.

The 32 ton Schenck HM7 U/S balancing machine is located at Marthinusen & Coutts’ 9 500 m²

high-tech workshop in Cleveland, near Johannesburg.

makes the bolt self-locking.

Advantages of this re-usable system

include maximum safety when locking

fasteners, easy assembly and disassem-

bly, positive locking at low or high preload

levels and minimum surface marring or

scratching. This system, which has the

same temperature characteristics as a

standard bolt or nut, resists loosening

caused by vibration and dynamic loads

and the locking effect is not affected by

lubrication.

For a permanent, guaranteed clamp

application, BMG recommends Huck

structural rivets and lock bolt solutions

and for extreme temperatures and chal-

lenging environments, the Thome and

Schwind range of specialised fasteners

is recommended.

For high strength challenges, the

Nord-Lock Superbolt multi-jackbolt

tensioner system, with advanced bolt-

ing technology, only requires simple

mechanical torque tools for installation,

eliminating the need for high strength

hydraulic torque tools.

To achieve the optimum

clamp, BMG offers Gedore

mechanical torque hand tools,

as well as Atlas Copco and

Ingersoll Rand pneumatic

and electronic assembly tools,

which use clutch and trans-

ducer technology to measure

and control tightening torque.

It is also possible to record

all joint tightening procedures

performed to ensure optimum

clamp in safety and quality

critical applications.

Other products include hand and

power tools, tool kits, personal protective

equipment, locks and lockouts, lifting

equipment and environmental products.

The range also encompasses measuring

and testing equipment, welding consum-

ables and abrasives, as well as cutting

and workshop equipment.

BMG’s network of over 120 branches

offers a technical advisory and support

service to ensure the correct

product is selected for

each specific applica-

tion. The company’s

advanced fastening

solutions and instal-

lation tools are designed to meet the

requirements of quality and safety critical

installations, also ensuring the best total

cost of ownership.