Epcos has developed an innovative solution for EMI suppression in DC motors in motor vehicles. The company's new CombiSuppressor comprises a film capacitor and a multilayer ceramic varistor connected in parallel in a plastic case. This packaging technology offers mechanical protection for the components and facilitates automatic picking and placement.
The B32529-V (RM 5) and B32521-V (RM 10) series are designed for operating temperatures from -55 to 125°C. The capacitors are characterised by high pulse load capability of up to 250 V/ms and meet ISO 7631. These components are available for operating voltages ranging from 22 to 45 V d.c. and threshold voltages of the varistor from 44 to 90 V. Their capacitances cover a range from 0,47 to 2,2 mF. All types have a leakage current of less than 50 mA.
Many top-range vehicles now employ over a 100 electric motors, all of which must operate interference-free in a sensitive environment. In order to eliminate electromagnetic interference directly at the motor - and thus to assure interference-free operation of all other electronic units in the vehicle - significantly more EMI suppression components must now be built into the same space compared with the requirements of just a few years ago. The CombiSuppressor has the functionality of two components in a single package and so offers significant benefits in space required, placement costs and logistics expenditures. Typical applications include windshield wipers, electrical seat adjusters, electrical windows, electrical sun-roofs, petrol and oil pumps as well as central locking systems.
Film capacitor alternative
As an alternative to the film capacitors, Epcos has also extended its range of super high-capacitance varistors (SHCVs) and is now offers the SHCV SR6 series in case size 1206. SHCVs are leaded components combining a multilayer varistor with a multilayer ceramic capacitor for overvoltage protection and radio interference suppression. Like the CombiSuppressor, the SR6 series was also specially developed for interference suppression in DC motors. With this, the requirements for improved technical properties such as constant capacitance with X7R ceramic, an extended temperature range from -55 to 125°C, significant miniaturisation of standard EMC components, and cost reduction is achieved.
SHCV SR6 types are currently available with ratings of 220 nF/14 V and 470 nF/35 V as well as 1 mF/20 V and 1 mF/35 V.
| Tel: | +27 11 458 9000 |
| Fax: | +27 11 458 9034/5 |
| Email: | [email protected] |
| www: | www.electrocomp.co.za |
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