Alcatel-Lucent 8DG59242AD PFDC20 Power Filter and Distribution Unit – Detailed Specification

The Alcatel-Lucent 8DG59242AD, also known as the PFDC20, is a high-performance DC power filter and distribution module designed for use in carrier-grade telecommunications equipment. This unit serves as a critical interface between the main -48 VDC power source and the chassis or system backplane, providing essential functions including EMI/RFI filtering, overcurrent protection, and surge suppression. Its compact design and robust construction ensure reliable power delivery in central offices, remote shelters, and outdoor cabinets.

The primary function of the PFDC20 is to filter conducted electromagnetic interference (EMI) and radio frequency interference (RFI) from the DC power line, ensuring that sensitive electronic circuits within the chassis receive clean, noise-free power. The integrated EMI filter is a common-mode and differential-mode type, with attenuation of up to 60 dB across the 10 kHz to 30 MHz frequency range. This filtering helps systems meet EMC compliance requirements and reduces the risk of interference with adjacent equipment.

The module includes a 20A hydraulic-magnetic circuit breaker that provides both overcurrent protection and a manual ON/OFF switch for the power feed. The breaker is rated for 20 A at -48 VDC, with a trip curve that accommodates the inrush currents typical of telecom equipment. It is trip-free, meaning it cannot be held in the ON position during a fault condition. A visible trip indicator shows the breaker status at a glance, and the handle can be locked in the OFF position for safety during maintenance.

In addition to the breaker, the PFDC20 incorporates a surge suppression stage using metal-oxide varistors (MOVs) and gas discharge tubes (GDTs) to clamp transient voltages caused by lightning strikes or power switching events. The surge protection complies with ITU-T K.20 and K.21 recommendations, providing robust protection against both common-mode and differential-mode surges up to 4 kV and 2 kA.

The unit is housed in a rugged steel enclosure with a powder-coated finish, measuring approximately 200 mm x 80 mm x 60 mm. It is designed for DIN-rail mounting or direct chassis mounting using M4 screws. The input and output connections are made via heavy-duty screw terminal blocks that accept wire sizes up to 10 AWG, ensuring low contact resistance and secure connections. The terminals are clearly labeled for input (+ and -) and output (+ and -), with an additional ground terminal for safety grounding.

An LED indicator on the front panel shows the presence of output voltage, while a test point allows for voltage measurement without disconnecting wires. The module also includes a remote alarm contact (Form C relay) that changes state when the breaker trips or when input voltage falls below a preset threshold, providing notification to the central monitoring system.

The PFDC20 is designed for continuous operation at full rated current in ambient temperatures from -25°C to +55°C, with derating above 50°C if mounted in confined spaces. It meets the vibration and shock requirements of GR-63-CORE and ETSI EN 300 019. The unit is RoHS compliant and carries CE and UL certifications.

In practice, the 8DG59242AD is typically installed at the top of a chassis or in a separate power distribution panel, feeding multiple chassis or shelves. It is commonly used in Alcatel-Lucent 7750 SR routers, 1850 TSS transport systems, and other carrier-grade platforms. Its filtering capability is particularly important when sharing the DC bus with switch-mode power supplies that generate high-frequency noise.

Maintenance is straightforward – the breaker can be tested periodically by manually tripping and resetting it. The surge protection components are self-healing for most transients, but the module should be replaced if surge counters indicate excessive events. Regular inspection of connections for tightness is recommended.

In summary, the Alcatel-Lucent 8DG59242AD PFDC20 Power Filter is an essential component for ensuring clean, protected, and manageable DC power distribution in telecom environments. Its combination of EMI filtering, overcurrent protection, surge suppression, and remote monitoring makes it a reliable and valuable asset for network infrastructure.