Q @ amperage difference for WD My Book power adapter

[Slugbait]

The wife lost her power adapter for her WD My Book external drive. The adapter for my older My Book drives works fine with her drive...amperage is 0.7A.

I found an adapter at a garage sale that matches V, Hz and VA. However, amperage is 0.8A.

Is 0.1A difference gonna be OK with her external drive? Does it even matter, or will it fry her external drive?

 

[lakedude]

Output volts must be the same or very similar.

Hz? AC power is 60 Hz in the US but most of these adapters output DC which does not have a Hz rating.

The VA and A of the adapter must equal or larger than the device needs.

In other words the 0.8A will be fine.

One hugely important thing is polarity.

If the adapters are DC you must make sure that the adapters are the same polarity.

If they are not you will need to swap polarity on the garage sale adapter to match the drive.

A brand new My Book adapter is not all that expensive...

http://www.amazon.com/WD1600B014-RN...N-WD1200B014-RNU-WD2500B015-RNN/dp/B0030BBH5I

 

[krnmastersgt]

I don't believe that the drive will draw more than the necessary .8A, a difference in voltage would kill it or just not cause it to work properly but I believe the amperage rating on adapters is typically just the maximum possible draw, not what it will always be running at.

 

[lakedude]

i = e/r

Current (Amps) equals Electromotive Force (Volts) divided by Resistance (Ohms).

If you feed the HD the correct Voltage the current drawn will be determined by the resistance of the drive. You could hook up the drive to a 100 A supply but the drive will only draw based on the above formula.

There would only be a problem if the power supply could not provide the needed current. A higher current power supply will not force more current into the drive, rather the drive will draw what it needs.

Voltage is Electromotive FORCE so too much Voltage could possibly force too much current into the drive.

 

[mfenn]

The wife lost her power adapter for her WD My Book external drive. The adapter for my older My Book drives works fine with her drive...amperage is 0.7A.

I found an adapter at a garage sale that matches V, Hz and VA. However, amperage is 0.8A.

Is 0.1A difference gonna be OK with her external drive? Does it even matter, or will it fry her external drive?

You're fine if the amperage is higher than you need as long as the DC output voltage (and tip polarity if it is a barrel plug) is the same. The Hz rating is probably for the AC input, which isn't relevant as far as the MyBook is concerned. That's presuming of course that the garage sale was in the US, which means that the AC side of the equation will be fine.

 

[Slugbait]

k, thx, I assumed it wouldn't matter. But it's her drive, all her backup pics from the D80 are there, she wanted to make sure. Something about trusting all you damn strangers over my opinion or something...