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6 EMC GUIDELINES

The following guidelines are intended to help vehicle manufacturers to meet the requirements of the EC directive

Electromagnetic Compatibility. The SuperSigma2 controller range is designed to meet EN61000-6-2 (industrial

immunity), EN61000-6-3 (residential emissions, Class B).

Any high speed switch is capable of generating harmonics at frequencies that are many multiples of its basic operating

frequency. It is the objective of a good installation to contain or absorb the resultant emissions.

All wiring is capable of acting as a receiving or transmitting antenna. Wiring should be arranged to take maximum

advantage of the structural metal work inherent in most vehicles. Vehicle metalwork should be electrically linked with

conductive braids.

6.1 Power Cables

All cables should be routed within the vehicle framework and kept as low in the structure as is practical – a cable run

within a main chassis member is better screened from the environment than one routed through or adjacent to an

overhead guard. Power cables should be kept short to minimize emitting and receiving surfaces. Shielding by the

structure may not always be sufficient – cables run through metal shrouds may be required to contain emissions.

Parallel runs of cables in common circuits can serve to cancel emissions – the battery positive and negative cables

following similar paths is an example.

Tie all cables into a fixed layout and do not deviate from the approved layout in production vehicles. A re-routed battery

cable could negate any approvals obtained.

6.2 Signal Cables

All wiring harnesses should be kept short. Wiring should be routed close to vehicle metalwork. All signal wires should be

kept clear of power cables or made from screened cable. When using screened cable, make sure only to earth it to one

point! Control wiring should be kept clear of power cables when it carries analogue information – for example,

accelerator wiring. Tie all wiring securely and ensure wiring always follows the same layout.

6.3 Controller

Thermal and EMC (emissive) requirements tend to be in opposition. Additional insulation between the controller

assembly and the vehicle frame work reduce capacitive coupling and hence emissions but tend to reduce thermal

ratings. A working balance needs to be established by experiment. The complete installation should be documented, in

detail, and faithfully reproduced on all production vehicles. When making changes, consider their effect on compliance

ahead of any consideration of cost reduction or other “improvement”.

DMC SuperSigma2 QRM User Manual

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