Before an electrical or electronic device can go on sale, it must undergo legally prescribed tests and be classified as electromagnetically compatible. This also applies to motors for ebikes and pedelecs. The decisive factor is whether, for example, they comply with the threshold values required for CE certification within corresponding basic product and technical standards. In future, the Chinese motor manufacturer Bafang will be able to carry out such tests for its products in its own laboratory.
Science in the service of industry
At the beginning of the month, the manufacturer announced that a dedicated EMC laboratory had been officially opened. Here, motors and their components can be tested for electrical compatibility. During the two-year construction period, Bafang said it had invested about 1.44 million euros at its headquarters in Suzhou near Shanghai. Various measuring facilities are gathered on an area of about 120 square metres, from which especially the development of new products should benefit. In addition, Bafang expects further positive effects:
- improved quality and efficiency across the company
- lower costs for complex EMC pre-testing and CE certification of components
- accelerated research and development processes
In a next step, Bafang would like to have the new laboratory accredited by the China National Accreditation Service for Conformity Assessment (CNAS) and further advance quality management. The new opening fits seamlessly into an already quite extensive research infrastructure of the manufacturer. It operates similar facilities where research is conducted into the environmental compatibility of products, mechanical reliability, the product ageing process and acoustics.
View into Bafang’s new EMC test laboratory
What disturbs or is disturbed?
Whether an electric or electronic device is electromagnetically incompatible plays an important role in the context of ebikes and pedelecs. After all, in addition to the motor, there are numerous other such components on such bicycles that can interfere with each other. This happens when a device conducts its voltage or current. This is called electromagnetic interference. In an EMC laboratory, it can be determined how robust devices are in relation to their electromagnetic environment, i.e. whether they themselves cause interference and are disturbed.
In order to get to the bottom of these phenomena, the Bafang EMC laboratory has, among other things, a semi-absorber chamber, also called a semi-anechoic chamber and abbreviated as SAC. This room is equipped with absorbers or absorbent materials on the walls and ceiling. The floor, on the other hand, is covered with particularly conductive and electrically interconnected solid metal plates. This has the great advantage that this chamber can be walked on directly. It is suitable for testing the immunity to interference. Another part of the EMC laboratory is a shielded room specially made of metal panels and integrated shielding seals, called EM Shielding Room.
EMC tests also for complete bikes
For bicycle manufacturers, a project like this one from Bafang brings some relief when building an ebike. They can assume more reliably than before that these components will not cause electromagnetic problems during integration. However, as stipulated in the DIN EN 15194:17 directive, this does not exempt bike builders from further EMC testing. Instead, the ebike system as a whole must comply with the standards. This includes chargers, batteries, displays, lighting, any sensors installed, as well as all cables, switches, controllers and voltage converters. Usually, bicycle manufacturers do not operate their own laboratories, but cooperate with specialised testing institutes for these analyses.
The bicycle manufacturer Rotwild works together with Hansecontrol Zertifizierungsgesellschaft mbH in Hamburg for the EMC tests of its bikes.
Pictures: Bafang Electric (Suzhou) Co., Ltd.; ADP Engineering GmbH
