Is it because some of the energy is transformed into heat and sound?
2007-11-04 10:00:55 · 7 answers · asked by GK27V6 1 in Science & Mathematics ➔ Physics
Generally, that's right. There are exceptions. Some motors have been made that are 100% + efficient. (u > 0). The Adams Generator for example.
2007-11-04 10:09:27 · answer #1 · answered by AussieGent 4 · 0⤊ 1⤋
There are a number of sources of losses in an electric motor.
Iron and windage are the main ones. The iron becomes a magnet but the polarity is continually reversed. The iron resists this change (lamination's help). The motor needs cooling, this is produced by a fan that requires energy to move air over the motor in addition to other air currents created by rotor parts.
There are also other smaller losses such as resistance and friction losses.
2007-11-06 08:28:52 · answer #2 · answered by Poor one 6 · 0⤊ 0⤋
There's always resistance in the electrical wires (which could be nearly eliminated with super conducting wires). There's nearly always some friction - maybe a magnetic bearing with an enclosed motor in a vacuum would eliminate that, but then you'd have to power the magnet (or it's control circuit) and that would take energy.
2007-11-04 11:12:11 · answer #3 · answered by Doug B 3 · 0⤊ 0⤋
In any machine, there are always some losses of energy to heat generation due to friction and the vibration it may cause.
2007-11-04 10:14:15 · answer #4 · answered by Norrie 7 · 0⤊ 0⤋
Much of the energy is used just to power itself and overcome friction.
2007-11-04 10:07:33 · answer #5 · answered by Bob H 7 · 0⤊ 0⤋
Your answer is correct, but you can add Resistance, Impedance, and Friction.
2007-11-04 10:23:17 · answer #6 · answered by Philip H 7 · 0⤊ 0⤋
Second law of thermodynamics
2016-05-27 08:52:52 · answer #7 · answered by ? 3 · 0⤊ 0⤋