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Voltage level of Rectifier for Telecom use

  1. Nov 21, 2013 #1
    Hi everyone,
    anybody knows what's the general voltage level that we use for the rectifier in telecom power supply.

    According to the user's requirement, it says:
    a) AC to DC Converters: Minimum 8000W @ -48V
    b) DC to DC down Converters: Minimum 2000W @ +24V (Optional)

    1) The system must be capable of supplying a minimum load of 6000W at a nominal voltage of -48V (Positive Ground). In addition the system must have a minimum of 2000W redundancy.
    2) The system shall be capable of supplying a minimum load of 1000W at a nominal voltage of +24V (Negative Ground). In addition a minimum of 1000W redundancy must be catered for. (Optional)
    3) The DC supply must consist of suitable components configured to provide (N+1) redundancy. In the (N+1) configuration the “N” = total load required plus charge (under normal operations) while the “+1” caters for redundancy in the event of module failure. Modules must be ‘hot’ swappable, soft starting, and load sharing.
    4) The Power System shall offer duel stage Low Volt Disconnecting devices in High and Low Priority groups to prevent any damage to batteries.

    The Low Priority: 75% of total Battery Capacity
    The High Priority: 25% of total Battery Capacity

    i.e. Low priority circuits will shed at a higher voltage level than High priority circuits. These voltage disconnect values will be determined by the user. When AC voltage is restored, the LVD-disconnect devices will automatically reconnect to restore system mode and charging.

    AC Distribution Requirement:
    1) The Power System must provide for AC input to the system. The system shall cater for a three phase supply and be easily adaptable to accept single phase supply as well.
    2) A triple pole isolator shall be provided to disconnect the system from the supply. Each rectifier will have its own individual circuit breaker.
    3) The AC distribution shall be suitably enclosed to prevent any accidental electrocution whilst working on the system.
    4) All cabling shall enter and exit through the top of the indoor cabinet
    5) All cabling shall enter and exit through the bottom of the outdoor cabinet

    DC Distribution requirement:
    The Power System must provide for the following DC load connections as a minimum:

    1) One -48V, 63 Amp High Priority disconnect circuit breaker
    2) Three -48V, 63 Amp Low Priority disconnect circuit breakers
    3) DC to DC down convertor input protection circuit breakers
    4) Two 32 Amp DC to DC down convertor output circuit breakers
    5) Four auxiliary -48V, 10 Amp circuit breakers

    These load disconnect voltages are user settable and dependant on battery technology. As a standard we have specified that the rectifiers supplied have the following base settings:

    6) Boost voltage = 2.40 volt per cell, i.e. 57.6 volt for total battery
    7) Normal float = 2.23 volt per cell, i.e. 53.52 volt for total battery
    8) Low priority disconnect (BTS) = 2.10V per cell, i.e. 50.40 volt for total battery
    9) High priority disconnect (Transmission) = 1.83V per cell, i.e. 43.92 volt for total battery

    According to my boss experience, it says normally we will use 24V, 48V or 60V for DC
    rectifier, so which level is the best for my case and give me the kindly reason/working
    principle behind. Thanks :)
  2. jcsd
  3. Nov 21, 2013 #2


    User Avatar

    Staff: Mentor

    Welcome to the PF.

    Your post makes no sense as written. "Rectifiers" are diodes, but you are using the term more like "power supply". Could you please check your translation and clarify?

    And the power levels you are quoting are more like you would encounter at a central switch building, supplying many telephone circuits. Can you please clarify why you are asking these questions? What are you trying to do?
  4. Nov 22, 2013 #3
    Hi Berkeman,

    Well, i think it is not so easy to post all the details of the document in the forum. So, can you please kindly pm your e-mail to my forum account so that we can discuss through e-mail, or even skype. Thanks.

    To let you have a better understand of the information,
    please check the files attached. Thanks.

    As a sales support and electrical engineer, i need to decide how many rectifiers do i need for the
    project with what kinds of the technical specifications.

    According to the quotation from some suppliers , they say we need 1 set of the DC-DC rectifier.
    So, I am not really sure according to the user requirement as I am so green in the company.

    Note, 48V is the output level of the rectifier (compulsory)

    Attached Files:

  5. Nov 22, 2013 #4


    User Avatar

    Staff: Mentor

    I'll look more at your attachments a bit later. For now, we hold conversations in the open forums so that everybody can benefit from the discussion.

    Also, your use of the word "rectifier" is incorrect. Please use the term "power supply" instead. Thanks.
  6. Nov 26, 2013 #5
    alright, thanks.
    Actually, that's the voltage level of "Power Supply" instead of "Rectifier" for telecom use.
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