|In today's power drive installations leakage currents are a hidden and ignored risk. Leakage current can cause RCDs (residual current device) to trip resulting in frequent system shut-downs. The LeaXield active filter module from EPCOS is a completely new solution for the minimization of earth leakage currents in such applications. The LeaXield module compensates leakage currents up to 1000mA and functions in frequencies ranging from 4kHz to 500kHz.|
The LeaXield active filter module is connected between the RCD and the EMC input filter of the converter in standard three-phase industrial power grids and does not require an additional power supply. LeaXield detects the common-mode currents on the load-side via a current sensing transformer. An amplifier generates an inverse of the leakage currents and feeds them to the power line via a capacitor network. This produces almost complete cancellation of the leakage currents.
LeaXield can also improve the EMC performance of power drive systems in the range up to around 500kHz. The new active filter module achieves typical common-mode attenuation values of up to 30dB at 4kHz, 40dB at 10kHz, and 15dB at 150kHz. The module can be retrofitted into existing converter-based installations in order to improve their EMC and the RCD compatibility of the power drive system.
• Compensation of earth leakage currents up to 1000mA
• Voltage range: 360VAC to 520VAC
• 3-phase industrial power grid
• Maximum power current: 150A (max.)
• Integrates amplifier, current transformer and power supply unit
• Improved common-mode attenuation in the frequency range from 4kHz to approx. 500kHz
• Requires no additional power supply
• Dimensions: 258x80x100mmRemarks:
• LeaXield is designed to attenuate common mode current disturbances from 1kHz and above. Attenuation is 20dB at 1kHz, 30dB at 4kHz and 40dB at 10kHz
• LeaXield is designed not to interfere with the power frequency current components (50Hz, 150Hz). Therefore the RCD operates as normal in response to power frequency fault earth current, including that generated by contact from persons.
• LeaXield is presently constructed for 3 phase 3 wire usage. In the future it is planned to adapt it for 3 phase 4 wire and single phase applications.
• LeaXield does not compensate DC leakage current.
• LeaXield is capacitively coupled to the power line. The reason for this is solely to provide an injection path for the compensation current.
• It is intended that LeaXield will be able to be certified to the LV and EMC directives together with the complete system.Main applications
• Power drive systems with frequency converters and long motor cables