Switch on by Using the Terminal Strip vs. Using the Switch on the External Hard Drive

Discussion in 'Apple' started by Joe, Feb 19, 2011.

  1. Joe

    Joe Guest

    I recently got an external hard drive, an OWC Mercury AL-Pro. It has an
    external power supply - from the size of it, I thinks it's a switch-mode.

    The only power switch is on the hard drive enclosure itself, not on the
    power supply.

    I have the thing plugged into a terminal strip that has individual
    switches for each outlet.

    Does it make any difference to use the switch on the terminal strip for
    the on-off switch and leave the switch on the enclosure always on?

    I'm thinking that maybe the switching power supply might put out a pulse
    at turn-on, and so it might be better to have the switch on the
    enclosure off until after the power supply has been turned on.


    --- Joe
    Joe, Feb 19, 2011
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  2. Joe

    Guest Guest

    no, but make sure you unmount the drive (or shut off the computer which
    unmounts all drives) before turning the drive off from either switch.
    Guest, Feb 19, 2011
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  3. Joe

    isw Guest

    The external power supply block will consume some power (but not much),
    whenever it is plugged in, even if the switch on the drive is off. If
    you turn off the AC, it will draw zero power.
    It would be a very poorly designed unit if it did anything like that.

    isw, Feb 19, 2011
  4. Joe

    Davoud Guest

    I did the same thing for years with an OWC drive that was not
    convenient to reach--turned it off at the power strip. I never had a
    problem. Just be sure to dismount the volume as you would any external
    volume before turning off the juice.

    Davoud, Feb 19, 2011
  5. Joe

    Fred Moore Guest

    That never stopped LaCie (or others) from making crappy power supplies.
    OWC seems a decent brand, so you're probably safe.
    Fred Moore, Feb 19, 2011
  6. Joe

    isw Guest

    I have no experience with their gear, but my understanding is not that
    the supplies put out "pulses" of any sort, but were simply unreliable
    and failed quickly. Big difference.

    The nature of switch-mode power supplies is that when powered up, they
    "sneak up" on the intended voltages, sort of like cranking the volume
    control after you've turned on the radio, just until it's loud enough.

    isw, Feb 19, 2011
  7. Joe

    Fred Moore Guest

    I basically agree with your point. However, _any_ time a power switch is
    closed on a live line, there is a switching transient. How potentially
    dangerous it is depends on many things, including the baseline voltage
    and current load, the capacitors downstream, any inductors upstream,
    whatever buffering components have been added, and how fragile the
    connected equipment is. Cheap power supply designs are more likely to
    let damaging transients through.
    Fred Moore, Feb 20, 2011
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