PWRCO - eNET REMOTE POWER FEEDER

The ENET PWR2CO remote power feeder complies with the relevant safety standards (IEC-60950-21 / ITU-K.50) for remote-feeding of the telecommunication equipment in the access network, the equipment which is not placed beyond the public network interface, and is not expected to be accessed or handled by the customer:

 Voltage and current limits

This Recommendation defines two methods for safe powering of telecommunication systems over the network. They are both based on IEC/TR2 60479-1 [5]. The first method limits the voltage so that the insulation or the resistance of the body limits the current conducted by service personnel to tolerable levels. The second method limits the current of the remote power feeding circuit so that higher voltages can be allowed.

Method 1: Voltage limited RFT circuits

This method is defined as the RFT-V circuit in Annex A. 

Under normal operating conditions, a RFT-V circuit shall comply with all of the following requirements: 

a) the steady state open circuit voltage from each conductor to earth that is supplied to a telecommunication network shall not exceed: 

• 140 V d.c.; or

• 200 V d.c. if the short circuit current is limited to 10 mA d.c.; 

b) the maximum power that can be delivered to any load connected to the telecommunication network shall be limited to 100 VA after 1 s (steady state condition in operation);

c) the steady state current that can flow into the telecommunication network shall comply with clause 6.3 of IEC 60950 [2].  

Method 2: Current limited RFT circuits

This method is defined as the RFT-C circuit in Annex B. 

Under normal operating conditions, a RFT-C circuit shall comply with all of the following requirements: 

a) the steady state current that can flow from the RFT-C circuit supply equipment into the telecommunication network shall not exceed 60 mA d.c. under any load condition; 

b) the steady state current that can flow from one conductor of the RFT-C circuit supply equipment through the telecommunication network to earth shall not exceed 2 mA d.c.; 

c) if the voltage rating of the wiring of the telecommunication network is specified, the supply voltage shall be limited to this value or to a maximum value of 1500 V, whichever is lower; or 

if the voltage rating of the wiring of the telecommunication network is not specified, the supply voltage shall be limited to 800 V between conductors of the telecommunication network. 

ENET PWR2CO 2-CHANNEL REMOTE POWER FEEDER 

In the subrack version, each 2-channel remote power feeder module is inserted in its own 19“ subrack. Placed near a DSLAM, the subrack, with the capacity of 10 modules (20 channels), feeds 20 ENET multiplexers. All the wiring, for -48V power supply, a twisted-pair to the eNET-8R+ ADSL PGS, and a twisted-pair to the DSLAM, are done on the back side of the subrack.  

The state of each channel is indicated by 4 light-indicators: two indicate voltage presence, and the other two indicate faults ( overcurrent and discharge to earth) 

The twisted-pair voltage and the maximum current comply with recommendation ITU-K.50. The lower class of the line voltage can be used (≤140V) because the ENET is a low-power device (<10W). In case of any line faults, the feeder immediately cuts off the line voltage; and when the normal line condition is attained, the feeder automatically restores the line voltage again. 

The remote feeding twisted-pairs have a two-stage overvoltage protection: 

The power feeder input voltages: 

·        Nominal -48 VDC

·        Input range -40.5 VDC to -57 VDC

·        Maximum input voltage -72 VDC 

The input circuit on each power feeder module is fitted with a fuse and, against transmission or reception of noise, an LC filter circuit. 

In the rack version of the feeder, the module of the standard hight (1U) is inserted into a 19" rack. The rack version is suitable for smaller concentrations of modules and does not require subracks. All the wiring is done on the back, but the indicators and the power switch are placed on the front side. The functionality of both versions (rack or subrack) of the remote power feeder is the same. 

Each power channel (in both versions) is addressable; therefore, it can be integrated in the management system. This integration is based on an added management module with a serial link to the power feeder and an Ethernet link towards the mangement system. The management system checks the functionality of each channel and controls its voltage level.

                    

          

 

 

 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
           
       
         
               
     
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