Page 32 - Industrial Technology July 2021

MACHINE BUILDING

GUIDANCE ON GEARS

GEARS & GEARED MOTORS
5 QUESTIONS TO ASK BEFORE

YOU BUY A GEARED MOTOR

he global geared motor market is expected to
reach approximately $32.9 billion by 2025. But,
before plant operators and mechanical engineers
Tinvest in the latest geared motor technology, what
are the key purchasing considerations? Here, Marek
Lukaszczyk of gearbox, motor and drive manufacturer
Weg, explains five questions to ask before you buy a
geared motor.
Gears are among the most important components in
many drive trains in industry. They are primarily used in
combination with an electric motor to set machines and
systems in motion and keep them moving. Due to the
large number of geared motors available on the market,
there are countless technical characteristics that can be
used to assess the quality, reliability and cost-benefit ratio
of a geared motor. So, where do you start?

1. Does the geared motor offer an optimal cost-benefit
ratio? Naturally, a gear unit with a good cost-benefit ratio
will be preferred to a gear unit that performs very well but
is too expensive to run. Maintenance costs are an
important segment of lifetime costs. If a gear unit is
particularly robust and dependable, it results in less call
outs and has a positive effect on system availability.
Lifetime lubrication for example, is a good low- well as the type of shaft seal rings and shaft material, higher cost, they have clear cost savings and
maintenance indicator that could make a huge difference should be considered depending on where the unit will be environmental benefits in the medium to long term. In
in cost of ownership. used. fact, energy costs account for approximately 90 per cent
It’s also important to consider the technical While there is no one size fits all response to this of the total life cycle costs of geared motors.
requirements of the application, as if these are not question, the more clearly defined the initial specification, Modern gear units are ultra-efficient: Only about 1.5
optimally met, this can incur additional long-term costs. the less modifications required. per cent of dissipated power is assumed for each ratio
Factors such as power, speed and torque are fundamental stage. With a good gear unit, the developers will have
to any application, and directly affect the size and costs of 3. How can I identify a good gear unit? When purchasing analysed and optimised potential sources of dissipation,
a geared motor. If for instance, the combination of motor geared motors, certifications are important, especially for example, by reducing the gear splashing losses.
and gear unit is incorrectly selected, energy efficiency is when they are destined for worldwide use. For example, Combine gear units offering efficient power transmission
significantly reduced, which will have a negative effect on the CE marking is mandatory for Europe and proves that with IE3 or IE4 mounted motors for the ideal solution.
the cost-benefit ratio. the product meets the applicable design requirements.
In addition, the versatility of the unit must be 5. Is my manufacturer’s global supply chain and service
2. Which gear unit best suits my application? In industry, considered. There is no global standard line voltage and it reliable? Finally, if your equipment unexpectedly fails, the
gear drives are primarily used. These include helical gear, can vary significantly depending on the country fast delivery of spare parts is crucial to avoid unnecessary
bevel gear, parallel shaft gear and worm gear units, which concerned. A versatile unit will cover the line voltages in downtime. Efficiency in the supply chain shouldn’t be
make up the majority of all installed gears, with planetary use in the major global markets (110–690 V – 50/60 Hz), ignored at the procurement stage. When faced with the
gears used to a lesser extent. Design differs depending on meaning that they can be used worldwide with simple decision between an inexpensive gear unit, which cannot
the application in which the geared motors are to be used. voltage switching. be delivered quickly and a slightly more costly unit with a
All application conditions need to be taken into This reduces the expense considerably, as many reliable and rapid global service network, the latter offers
consideration. These include space requirements, drive asynchronous motors are very limited in terms of voltage a better cost-benefit ratio. The former could result in
output, drive control and other ambient conditions. To switching due to their winding design. Weg’s EUSAS productivity losses not only to the company, but also its
make the right choice, it should also be clear what loads motor is a good example of a versatile option that can be customers, which could have negative implications for the
the gear unit will be exposed to in the specific application. used in Europe, USA and Asia. company’s reputation.
The spatial conditions of the application and the It’s only when these characteristics are considered
installation dimensions of the geared motors are key 4. Is the gear unit energy efficient? Efficiency is a very together that a plant operator or mechanical engineer
factors, especially when retrofitting. Design specifications important factor – both for environmental and financial can truly make the best purchasing decision.
such as different coating systems, the protection class, as reasons. While energy efficient products may have a MORE INFORMATION: www.weg.net

32 INDUSTRIAL TECHNOLOGY • July 2021