Surge Protection Considerations

The importance of choosing the right surge protection device during elevator modernisation to reduce unnecessary downtime

by John Mitchell

Advances in elevator technology have been critical facilitators of the high-rise structures that define urban skylines. However, upgrades in elevator safety, robustness, quality, space efficiency and performance are needed to support infrastructure development and meet societal needs. It is important to opt for the right surge protection device (SPD) to reduce unnecessary downtime.

Elevator modernisation can feel like an expensive and time-consuming undertaking. Before embarking on a modernisation project, a thorough survey is undertaken to assess the current performance of the system. Once armed with this information, an assessment of whether a modernisation is necessary and, crucially, whether it makes business sense, can begin.

One of the most important considerations should be the safety of the passengers, maintenance personnel and the lift system. A more modern, safer elevator that complies with the latest standards and offers improved reliability is clearly the desired outcome. However, an important safety consideration that is often overlooked is the effectiveness of the system’s SPD.

Reducing Downtime and Maintenance Costs

Elevators typically have service lives of more than 20 years, but during this time, their performance can decline, leading to increased maintenance costs, increased energy usage and the risk of downtime.

Modernisation can make elevators more energy efficient and reduce energy costs by feeding otherwise wasted energy back into the building whenever the elevator is travelling in an out-of-balance direction, rather than releasing it in the form of heat through braking resistors.

For example, CP Automation’s Magnetek range of elevator products include drives with built-in regenerative technology and also separate regenerative “bolt-on” modules that can be retrofitted to any existing AC drive to produce substantial energy savings — savings which can be calculated using our online Energy Savings Calculator tool.  

However, as the hardware and software used in elevator applications has advanced, this has brought about an entirely new set of problems and maintenance considerations. While hardware and software are more reliable than ever before, they are also highly sensitive to fluctuations in power surges.

High voltage surges are normally covered by surge protectors. However, traditional SPDs do not account for low-level transient surges that can occur countless times a day, exaggerated by variable speed drives (VSD) usage. Don’t let the name fool you — these transient surges in the sine wave are very damaging to electrical equipment, as the additional peaks and troughs in the sine wave cause confusion to sensitive devices and machines.

This can cause recurring random failures, lockups and deprogramming, such as those experienced by human machine interfaces (HMIs) used in destination dispatch systems on each floor. To protect the electrical control system, the VSD and the lift controller from transients, a more sophisticated transient protection system is needed. Downtime and maintenance can be eliminated if the right surge protection, such as SineTamer, is in place.

Crucially, SineTamer’s frequency attenuation network monitors the frequency, not just the voltage. The engineered transient disturbance filter is designed to monitor all 360° of the sine wave, making it capable of detecting rapid changes in frequency. This vigilance, in turn, prevents issues caused by false zero crossings of the sine wave.

When approached carefully, modernisation — partial or complete — can lower repair costs, reduce faults and increase energy savings while improving comfort, efficiency, safety and aesthetics. However, it’s important that facilities managers do not overlook the importance of protecting this sensitive equipment from harmful power surges.