Using Regenerative VSD Braking to improve your energy efficiency

When an electric car brakes, its kinetic energy is converted into electricity and returned to the car’s batteries to extend the driving distance. This same principle, Regenerative Braking, can also be applied to electric motors used in a wide variety of industrial applications where frequent braking is required or when stopping high inertia loads. Examples where Regenerative Braking can be applied include centrifuges and separators used in the dairy industry, shredders and chippers/debarkers for the milling industry, and grinders and presses at ore refineries.

A regenerative Variable Speed Drive (VSD) captures wasted energy and returns it to the network so it can be used by other equipment, offering substantial improvements in energy efficiency, and reducing overall energy costs.

For example, the annual savings of a waste handling crane powered with a 55kW hoisting motor, 9 kW long travel motor and a 4.5kW trolley motor was 15.6 megawatt/hour (MWh) and $2,750 based on the measurements at a customer site. This equates to a 32% energy saving compared to the previously used technology of resistor braking.

With a traditional resistor and mechanical braking methods, excess energy is dissipated as heat, which often requires additional cooling in an electrical room to cope with it. When regenerative braking is used, the braking energy is not wasted as heat and further cost savings can be achieved with reduced cabinet building costs as the installation footprint is smaller due to the lack of need for external braking components.

Ongoing maintenance

All VSDs require regular maintenance and with temperatures increasing, putting more load on the drive’s cooling system, now is a good time to make sure your Variable Speed Drives are in top condition for the summer period to ensure there is no disruption to production.

Key checks include:

• Visual check:
  To make sure the drive is clean; the cooling fan and cooling system are all in good condition. Dust on VSD hardware can cause a lack of airflow, diminishing performance. Dust also absorbs moisture which can contribute to failure. Connections should also be checked as heat cycles and mechanical vibration can lead to sub-standard connection and cause erratic operation resulting in damage to machinery.
• Settings:
  Parameter settings should be checked and recoded so that if there is a failure, the drive can be easily replaced. EAS utilise Drive Software to enable us to upload the correct settings straight back into your drive to get it up and running as quickly as possible.
• Stocktake of spare parts:
  By performing a stock take of the spare parts available we can ensure that any breakdowns can be handled quickly and efficiently. It also gives the opportunity to identify drives where spare parts are no longer available so that a planned upgrade of the drive can be scheduled where it will be least disruptive to production.

EAS are experts in installing and maintaining Variable Speed Drives. We can assist you with your regular preventative maintenance checks, servicing and can provide advice and installation for regenerative braking systems on new and existing VSDs, depending on age and condition.

If you want to know whether a regenerative braking system may be a good option for your plant, or need to schedule in your VSD preventative maintenance checks; get in touch with the EAS team today on 834 0505.