Mechanical Technology July 2016

Mechanical Technology — July 2016

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On the cover

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tlas Copco is continuing to

expand its premium GA, GA+,

GA VSD and GA VSD+ com-

pressor ranges, most recently

with the inclusion of 200 and 250 kW

VSD (variable speed drive) versions of its

GA oil-injected, screw compressors. “We

had a gap in our VSD range between 160

and 315 kW. We have now closed this

gap with the inclusion of VSD versions for

our GA 200 and GA 250 models,” Van

Wyk reveals, adding: “while VSD com-

pressors are not widely used in mines,

we have seen immediate success with

these energy conscious clients.”

Operating at medium to high pressure

– 5.5 bar up to 13 bar – the GA range

is ideal for the manufacturing sector,

typically energising robots, actuators and

clamps on automatic production lines.

Talking about the role of VSD versions,

Van Wyk explains that if a compressor

can be run at maximum capacity, 24/7,

then the addition of a VSD is not neces-

sary. “But if the compressors are regularly

run at below maximum capacity, then it

is usually more efficient to use a VSD

to match the compressor’s speed to the

compressed air demand,” he explains.

Hence the need for the two new addi-

tions, so that compressors with smaller

motors can be used for 200 and 250 kW

VSD applications. “These additions give

us energy efficient VSD compressor op-

tions spanning the power range all the

way from 7.0 to 315 kW,” Van Wyk tells

MechTech

“By combining a fixed speed compres-

sor with a second VSD compressor, one

can cater for both variable demand and,

at the same time, provide a level of re-

dundancy for situations when one of the

compressors needs to be serviced. And

if full redundancy and variable flow are

required, we recommend two fixed-speed

compressors plus a VSD, with the two

fixed speeds being alternated to supply

minimum continuous demand and the

VSD providing the variable top-up flow,”

he adds.

On the ultra-high efficiency side,

Ackerman says that the permanent

magnet VSD+ range of compressors

is also being extended. “Our GA VSD+

compressors have been completely re-

designed to make best possible use

of Atlas Copco-patented permanent

magnet (PM) motor and drive train

technology.

“When used on a variable speed

application, VSD+ compressors

offer up to 50% better energy ef-

ficiency as compared to their fixed

speed siblings,” he assures.

In addition, permanent magnet

motors and the new compressor

design enable full speed operation at

better efficiencies than fixed speed

equivalents. “The PMmotor enables

a VSD+ compressor to be used at

up to 100% of its rating without effi-

ciency drop off,” Ackerman explains,

adding that the GA VSD+ range

with permanent magnet motors has

been extended to include options of

up to a 75 kW nearly twice the capacity

of the previous largest (37 kW).

Atlas Copco Compressor Technique in South Africa is expanding its offering

of industrial compressors, nitrogen and oxygen generators, air treatment

equipment, blowers and low-pressure compressors to better meet application-

specific needs in the local market.

MechTech

talks to business line managers

Charl Ackerman and Pieter van Wyk.

With the inclusion of VSD versions for its GA

200 and GA 250 models, Atlas Copco has

now closed a gap in its oil-injected screw

compressor range.

Atlas Copco’s GA VSD+ compressors have been com-

pletely redesigned to make best possible use of patented

permanent magnet (PM) motor and drive train technology.

Compressor Technique expands

“This is a game-changing innovation

for general industry. The GA 7-75 VSD+

variable speed drive compressor range

offers improved performance, silent op-

eration (down to 62 dB) and a compact

footprint, thanks to its vertical drive train

design.

“The patent-pending PM motor has

been in-house designed and is directly

coupled to Atlas Copco’s best-in-class

screw element. This technology will set

new standards in the industry for years

to come,” Ackerman believes.

Low-pressure solutions

Also expanding is Atlas Copco’s low-pres-

sure range. “Low pressure compressors

are widely used for wastewater treat-

ment; pneumatic conveying of powders

such as cement or dry food powders;

for iron smelting furnaces; and in the

chemical industry for processes such

as sulfation. Across our ranges, which

include roots and screw type blowers;

screw and centrifugal compressor op-

tions; along with multistage centrifugal

compressors, we have low-pressure solu-

tions from 200 mbar to 4.0 bar delivering

air flows from 20 to 55 000 m

/h,” Van

Wyk notes.

“In the past, we have been weak in

this area. We had a screw (ZS) and a

centrifugal (ZB) offering, but these had

a maximum capacity of 160 kW. Our ZS

offering now goes up to 355 kW, and

these also now include VSD options,”