FEATURE DRIVES, CONTROLS & MOTORS KEEP THE NOISE DOWN!
In the medical industry, low noise machinery can help comfort the patient; and in the home or car, quiet products give the impression they are high quality, high performance. Dave Walsha, commercial development officer at precision drive system supplier EMS, explains why specifying quiet micromotor systems can be beneficial for the application
M
otors are used to power many everyday items and, unless you can hear them, they tend to go unnoticed. In the home, a noisy
fridge, may give the impression it’s not working properly; and a noisy motor on disability aids such as a stair or bath lift may result in the user thinking the equipment is struggling. On vehicles, add-ons such as motorised
sun roof shades and automatic passenger assistance steps, require minimal sound to convey high quality. Then, in offices, motor noise is an important consideration where there are rooms filled with equipment such as computer fans, air conditioning units and printers. In the medical industry, meanwhile, equipment powered
by quiet motors – including ventilators – helps to put the patient at ease and enables them to be treated more comfortably.
CONSIDERING THE MOTOR SYSTEM Keeping a motorised appliance quiet requires careful consideration of the motor system as a whole, including the motor and associated gearbox. Within the motor, changing the bearing material and shape – such as upgrading to a high-quality steel, deep groove, ball bearing – can be beneficial. Designers need to ensure the internal rotor is well-balanced. Aligning the
centre of mass as close to the geometric centre as possible can significantly lower noise by reducing vibration. As motor noise is kinetic energy wasted as sound energy, using a high efficiency motor will also lower sound levels. Engineers must carefully consider noise during the whole design process
MEETING THE ECODESIGN DIRECTIVE
In the summer of 2021, the new Ecodesign Directive comes into force throughout Europe and the energy efficiency of standard asynchronous
motors will need to continue to be improved. To help, Lenze has compiled easy-to-understand basic information as well as a complete checklist for OEMs and machine operators. The company is also launching a new motor platform – the
m500 series – and will be introducing an intelligent web-based planning and conversion tool. Designed to be future-proof as a drive solution, the m500 motor platform is primarily intended to be combined with Lenze gearboxes from the g500 family and the i500 inverter series. Savings in energy consumption of 20% to 50% can be achieved in the drive system, depending on the machine type and the specific requirements. According to the company, the greatest potential can be
exploited if the drive dimensioning and motion profiles correspond to the actual process requirements. The use of inverters to adjust the power or feeding the brake energy into the DC link are further possibilities for optimisation.
Lenze 32 JUNE 2020 | DESIGN SOLUTIONS
www.lenze.com DRIVING EFFICIENT TEA PRODUCTION
Withering is the process used to dry tea leaves and the quality of the tea will mainly depend on this. Fans are used to remove moisture from the black tea leaves, drying them 40-50% during a 12 to 18-hour period – and in Sri Lanka nearly 50% of energy consumption is due to this. The fans would run at a constant speed, blowing air through dampers to dry the
leaves and these dampers would be manually controlled to adjust the airflow. However, in 2018, hundreds of Invertek’s Optidrive Eco drives were installed and commissioned in many tea plantations throughout the country as part of NAMA, a project led by the Sri Lanka Sustainable Energy Authority, under the direction of the Ministry of Power and Renewable Energy, and the United Nations Development Programme, to reduce greenhouse gas emissions through greater efficiencies. The new drives meant the airflow could be controlled more accurately and efficiently
by varying the fan speed rather than adjusting the dampers, considerably reduced energy usage, with energy savings of around 20-25%. In this application, the Optidrive Eco VFD’s have IP66 enclosures for maximum protection against dust and the water. According to tea manufacturers, the introduction of the
VFDs has not only reduced energy costs but increased the quality of the tea leaves. VFDs are also being introduced to other parts of the tea
manufacturing process, including controlling furnaces and the amount of energy they produce.
Invertek Drives
www.invertekdrives.com
of a gearbox in order for it to produce minimal sound. Adjusting the tolerancing of the gearbox to minimise pitch, tooth profile, lead and runout errors ensures precise alignment of teeth for lower vibration. In addition, reinforcing the gearbox housing to increase stability can alter noise levels by minimising vibration. Trialling a more viscous lubricant can reduce friction, but it’s important to ensure the
lubricant is compatible with the motor. Once the motor system has been built, it must be analysed for sound using an accelerometer, with repeated prototype testing and refinement.
To meet application demands, EMS not only manufactures a range of motor systems, but offers a bespoke design service to suit specific requirements. Motor systems can be catered to
low noise requirements from concept to production. While micromotors won’t produce volcanic levels of noise, they can still
be problematic. By taking a considered approach to the design process, and using an accelerometer for refinement, motors can keep the noise down.
Electro Mechanical Systems
www.ems-limited.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
