Do all 3T external drives have a separate power supply?

[Metspitzer]

Do all 3T external drives have a separate power supply?

I have a 300G Seagate and a 300G WD external drive and neither of them
have a power supply. I am looking to get a 3T drive and the few I
have looked at have external power supplies. I am guessing they all
have one because they all need one. Correct?

 

[Charlie Hoffpauir]

Do all 3T external drives have a separate power supply?

I have a 300G Seagate and a 300G WD external drive and neither of them
have a power supply. I am looking to get a 3T drive and the few I
have looked at have external power supplies. I am guessing they all
have one because they all need one. Correct?

Some external drives, based on an internal 2 1/2 inch disk (primarily
a laptop disk), do not come with external Power supplies because the
power from the USB port is sufficient..... (although some of them come
with a special USB cable that allows you to take power from two USB
ports). Some external drives are based on a 3 1/2 inch disk (normally
a desktop disk). AFAIK all of these need an external PS. I've not
heard of any 3 TB 2 1/5 inch disks, so I'm guessing that 3 TB drive is
based on a 3 1/2. and so will require a PS. My thinking is that the
need for a separate PS is based on the physical size of the disk, ie 2
1/2 or 3 1/2, not the actual capacity.

 

[Flasherly]

Do all 3T external drives have a separate power supply?

I have a 300G Seagate and a 300G WD external drive and neither of them
have a power supply. I am looking to get a 3T drive and the few I
have looked at have external power supplies. I am guessing they all
have one because they all need one. Correct?

How else could its fan inside work?

 

[Paul]

Do all 3T external drives have a separate power supply?

I have a 300G Seagate and a 300G WD external drive and neither of them
have a power supply. I am looking to get a 3T drive and the few I
have looked at have external power supplies. I am guessing they all
have one because they all need one. Correct?

2.5" drive
Power: 5V @ 1A spinup, 5V @ ~200ma read/write
Somewhere in that ballpark.
Sometimes requires a two-headed USB cable, on the enclosure,
to get sufficient spinup current.

3.5" drive
Power: 12V @ 0.6A, 5V @ 1A, rough figures.
There is no 12V on a USB cable.
Therefore, an adapter provides the 12-13W of power needed.
There is a fair spread of total power numbers, and some drives
need about half that amount of power. But still, need
a source of 12V. The 12V runs the motor, and might also
help power the actuator arm.

Optical drives have variants as well. Laptop optical drives
use 5V only for power. Desktop optical drives use 12V and 5V,
with power numbers that can be higher than a hard drive.
This leads to the same kind of observations, as in the
hard drive examples (laptop drive doesn't need the adapter
and runs off USB bus power).

The largest 2.5" hard drive, might be 1TB. Whereas
the 3.5" desktop hard drives, are available up to 4TB size.

HTH,
Paul

 

[Loren Pechtel]

Do all 3T external drives have a separate power supply?

I have a 300G Seagate and a 300G WD external drive and neither of them
have a power supply. I am looking to get a 3T drive and the few I
have looked at have external power supplies. I am guessing they all
have one because they all need one. Correct?

2.5" drives can run off two USB ports.

3.5" drives can't.

AFIAK the biggest 2.5" drive is currently 1tb.