Where does the power increase come from by increasing frequency from 50 to 60hz?

http://www.engineeringtoolbox.com/affinity-laws-d_408.html

in this link we can see on the graph that the increase in speed of a pump's impeller causes the pump to 'push' a liquid with more power at a higher pressure..

now when you change the current frequency of a pump from 50 to 60 the speed increases by 20% so this would mean according to the graph that the pump will push with more power..this means that this increase of power is coming from the motor driving the impeller...how does the increase in frequency cause an increase in power consumption by the motor? does it make it pull more current from its ource or a higher voltage? i know power=lVcos0(frequency is not in the formula)..Where does the power increase come from by increasing frequency from 50 to 60hz?Notwithstanding the rambling and rather academic dissertation by HASD, who seems not to have read the question, the situation is quite simple.



Assuming, as would often (but not always) be the case, that a motor can still operate normally and safely at the higher speed (60 Hz), then it would react fully automatically to any increase in its torque (as applied by the load) by simply drawing more current from its supply. As you correctly remark, frequency doesn't come into it. What the frequency basically does is determine the speed.



A motor itself is not able to alter the voltage with which it is supplied so its reaction is confined to drawing more current as its torque increases. It is the user who has to provide a suitable voltage for the motor and although most motors might work well at 60Hz on the same voltage as at 50, the ideal voltage would usually be higher by about 20%. If the user makes some or all of the voltage change, then the current change demanded by the motor will be correspondingly less.



I take the opportunity to recommend Alfonso to go back to school for while! There's an awful lot about electricity that he hasn't grasped very well. Meanwhile humanity would be better served by his silence.Where does the power increase come from by increasing frequency from 50 to 60hz?Uh.... No.

20% increase, must be living in dreamland. the example shows a 10% increase, and there's nothing in that link about increasing frequency.

If the frequency goes up to 60HZ it also means an increase in power being supplied to the motor, because the electricity is arriving more rapidly than before.

The power is averaged out instead of using peak voltage,so if power comes in more rapidly the averages will be higher.It's higher because less time is spent at zero and the peaks are coming in more frequently. it's kinda hard to show this without an example if a sine wave.

AN increase in power speeds up the motors turning rate, which gives more horsepower (voltage and current rates are moot points, they are both higher).Where does the power increase come from by increasing frequency from 50 to 60hz?The link you posted only seems to mention the obvious, namely the faster you turn the pump, the more power that must be used.



Now, what is NOT mentioned in the link is what is driving the pump. It could be a hand crank, a gasoline-powered engine, or an electric motor.



So... you seem to be interested in the case of driving the pump with an electric motor. Furthermore, you mention 50Hz vs 60Hz, which implies you are dealing with an AC system.



AC motors work by creating a rotating magnetic field in the stator. By switching from 50Hz to 60Hz, you are making this field turn faster.



If you use a synchronous AC motor (which is not common), then the motor MUST keep up with the rotating magnetic field (or the motor would quickly burn out).



On the other hand, it you use an AC induction motor (more common), the rotor is free to slip relative to the rotating magietic field, so (depending on the load), the switch from 50Hz to 60Hz may not change the speed much at all. If the load is very light then it will change by the 20% you mentioned.



An AC motor running at no-load is not really using much power at all even though it is spinning rapidly. As the load is increased (as will occur in the case of your pump), then the induced magnetic field in the rotor slips relative to the rotating field of the stator. It is the phase difference between the two that defines how much power is consumed (ignoring the losses due to the resistive component of the motor coils and magnetic hysterisis).