Help me understand optical drive power requirements

vbimport

#1

Hello,

I am trying to understand what the power ratings printed on optical drives mean. For example, the recent Plextor PX-891SA lists a power rating of DC 5V-1.5A / DC12-2.5A next to the serial number. What do these values mean? I think I understand the voltage rating, but I am not so sure about the amps.

Is that the power drawn by the optical drive? Or perhaps the maximum power that is safe to operate the drive?

This question has come to my attention as I am trying to find an external enclosure for my optical drive. I notice, however, a lot of external enclosures include a power output of DC12V-2.5A…which has me wondering if this is enough power to operate my drive…


#2

Hi,

this is the maximum electrical current the device can draw by design. To properly operate a certain drive, a power supply unit capable of delivering these currents at all given voltages is needed.
In case of the Plextor you mentioned, the power supply unit must be able to deliver 2.5A@12V PLUS 1.5A@5V.

Michael


#3

[QUOTE=mciahel;2722737]Hi,

this is the maximum electrical current the device can draw by design. To properly operate a certain drive, a power supply unit capable of delivering these currents at all given voltages is needed.
In case of the Plextor you mentioned, the power supply unit must be able to deliver 2.5A@12V PLUS 1.5A@5V.

Michael[/QUOTE]

Hello Mciahel,

Thank you for your helpful reply!

That is sort of what I was thinking it meant. So looking at external cases, I notice this one by cooldrives http://www.cooldrives.com/alpo5inexfia.html has an AC adapter that outputs DC 5V-1.5A / 12V-1.8A. Similarly, this enclosure from OWC http://eshop.macsales.com/item/OWC/MRSFW8U3/ lists an output supply of DC 12V-2.5A.

Based on my understanding of the listed Plextor power rating, these enclosures would not be able to power the Plextor optical drive as they don’t provide enough current (not to mention the bridge chipset + fan must require some current as well). The strange thing is that I contacted both these companies and was told by their tecnical support that their enclosures would work with all SATA Plextor and Lite-On drives.

So maybe I don’t understand the enclosure AC adapter power rating?
What am I missing here?:doh:


#4

First of all they will always say it’s compatible, until it isn’t. This has to do with certain standards. They will always say they are approved for that standard.

Second of all it is a maximum rating. Your drive probably will not eat 2.5 Amps away, but it might. It is rated for that.

Long story short: Just agree you can return the external case with a full money back warranty if it will not work.


#5

Mr. Belvedere,

Thank you so much for your help!
I think it all makes sense now.

I guess I will go ahead and order the enclosure and just keep an eye out that the drive is able to reach full speed, use light scribe etc. before the return period is up.