Running a ~5V rated servo off an Arduino 3.3V pin?

Hey guys,

To cut a long story short, I've been running this servo using the 'Sweep' sketch that's one of the standard Arduino sketches.

What I don't understand is, when I decide to run the device using the 3.3V pin instead of the 5V pin - I notice that the servo runs virtually identically whilst utilising less voltage. When I use a multimeter to distinguish how much current is being drawn... (before I continue, I understand a multimeter isn't ideal - and that large fluctuations are often seen, but it's a rough guide)... I notice that during rotation the device can draw 40-60mA, and when it reverses the direction of rotation it can draw up to 140-160mA. Current drawn also seems to be roughly the same regardless if the servo is powered by 3.3 or 5V.

Does anyone have an explanation for this? I understand that servos use DC motors to convert electrical energy to mechanical energy - and this could explain my question, however there isn't really a decrease/increase in current when voltage is changed (which you'd normally expect a DC motor to behave). I apologise if this is an incredibly noob question.

Do you get the same variation in current when using 5v?

It is not recommended to power a servo from either the 5v or 3.3v pin.

...R

Robin2:
Do you get the same variation in current when using 5v?

It is not recommended to power a servo from either the 5v or 3.3v pin.

...R

For both voltages the current drawn does normally fluctuate between 30-60mA, unless the servo's rotation begins reversing. However during normal, smooth rotation, the servo draws roughly 45mA +/- 5mA when it supplied power from both the 3.3 and 5V pin.

I'm assuming drawing 50mA from the 3.3V is the accepted limit? (as per http://arduino.cc/en/Main/arduinoBoardUno)