I desoldered a component, HY-05 Electro-magnetic sound generator, from a broken motherboard. Its DCV is 3~8V, operating frequency 2400 plus or minus 200 Hz. I can get a small metallic sound with the operating voltage probably because the frequency is wrong. How can I adjust the frequency in the power supply of 50Hz? If the question is bizarre, it may be that the component is just broken.
Electronic – How to get higher frequency from DC power supply
frequencysound
Related Solutions
My answer applies to higher-than-1st-order systems.
There will always be a resonant point even if you can't see it. You need to understand how "poles" work. Take a look at this: -
Even if there doesn't appear to be a resonance in the bode plot there will be a "pole" that is present and this pole represents the resonant frequency even though the "dampening" is causing it not to appear in the bode plot. Here is what a 2nd order low pass filter looks like with varying degrees of Q (where Q = \$\dfrac{1}{2\zeta}\$): -
If you could determine the phase angle where the output shifted by 90 degrees from the input you would find the resonant frequency even if it doesn't appear to have a "peak" in the bode plot.
If you operate the motor at 5/6 of the 60 Hz rated voltage, the motor can be operated continuously at rated torque. The operating speed will be 5/6 of the rated 60 Hz speed and the power delivered will be 5/6 of the rated 60 Hz power. The efficiency, power factor, current and temperature rise will not change very much. The life expectancy will not change very much. The self-cooling capability will be reduced slightly because the rotor fins or shaft-mounted fan will be turning at 5/6 the 60 Hz speed. However, the iron losses will also be reduced due to the reduced frequency and the friction and windage losses will be reduced.
If you don't operate the motor at the proper voltage i.e. 5/6 of rated 60 Hz voltage, the effect will be the same as operating any other motor at the wrong voltage.
Re Comment
The proper 50 Hz voltage for a 220-240V, 60 Hz motor would be 183-200V. A supply that is nominally 220V would be 10-20% high for that motor. Below is a graph showing the major effects.
Image by Ed Cowern
Best Answer
According to the datasheet, you should give it a square wave with a duty cycle of 50% at a frequency of 2400 Hz with an amplitude of 5 V. You could make that with a 555 timer chip, 2 resistors, and 2 capacitors.
More details here.