Re: [CAD_CAM_EDM_DRO] Re: ...power...

At 10:56 PM 2/14/02 -0000, mariss92705 wrote:

>NCS,
>
>I guess it's my fault I haven't made my point clearly. Let me try
>again, using the "there is no such thing as a free lunch" method.
>
>Motors generate mechanical power. Dyno test data I have for a 4A, 3V
>double stack 34 motor (M092-FD08) is 108 Watts mechanical at 60VDC,
>or a little over 1/7 HP. While it is generating that power, it
>consumes 159W of electrical power for an efficiency of 108/159 or 68%.
>
>Let's get back to the 159W. Where does it come from if not the power
>supply? If you have 3 motors, then you will need 477W total. At
>60VDC, 7.95A is needed to deliver 477W.

Oops! You are correct, and I am wrong.

Indeed, if being wrong was an Olympic event, I think even the French judge
would
award me the gold! :-)

>You say 0.5A at 60VDC is fine. That is 30W. How do you get 108W motor
>shaft power while heating the motor with an additional 51W from a 30W
>supply? Remember, there is no such thing as a free lunch ;-/

I guess what I *meant* to say, was that all *other* things being equal
(same speed, load, etc),
if you double the supply voltage the current drawn would be halved.


- Dom