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What voltage and frequency are they rated ? Is this RMS Sine or low-duty-cycle pulsed ??
If you think of them as mega-tweeter loudspeakers, power handling etc may suggest driving them independently. 50 Watt RMS modular amps with sub-HiFi-grade THD are not expensive. Matching stereo PSUs, typically 28~36 Volts, are often available from same suppliers. You will have to fit a sizeable heat sink to each channel, devise a compatible signal source...
Driving them with a 'boost-type' power inverter would be a more elegant solution.
Some ultrasonic cleaners are using multiple transducers to increase the total power and achieve a more uniform intensity distribution in the cleaning container. I guess they are more often using parallel connection (lower voltage, less sensitive to resonance frequency difference), but series connection is possible in principle.
Do you mean that if a use 5 transducers rated 100w and connect them in parallel I can achieve 500w total power? I'm still new to all these. please help me. TIA.
If the rating is 50W per transducer...then this is independent of serial or parallel connection.
But total power is the sume of each single power.
Thus 5 x 100W = 500 W.
If you connect them in series you need to increase the voltage.
If you connect then in parallel you have will see increased current.
Because of each transducer has it's own impedance and resonant frequency ... a parealel connection is preferred.
With a series connection they electrically influence each other .. usually in a negative way.
I plan to build a 100w drive circuit. Would that be enough to drive two 50w transducer connected in parallel or do I have to drive them with separate drive circuit?
Common transducers (PZT) are operated close to their resonant frequencies by the driver. In other words, they form a part of the feedback loop. So the five transducers may have close frequencies but they may not be exactly identical.
It will be good to have independent drivers for all the five. But are you planning to place all the five on one vessel? You need to be careful because all of them will be oscillating at the same frequency but they will deliver less power individually.
Also try to see the vibration modes on the plate. Look for nodes and antinodes.
I'am trying to build a small ultrasonic cleaning tank (20 Liters). I have now in my possession 5 ultrasonic cleaning transducers they are also multi-frequency transducers and rated 50w each. I was wondering if I can drive these transducer with only a single drive circuit with 300w rating without any issues whatsoever.
I'am trying to build a small ultrasonic cleaning tank (20 Liters). I have now in my possession 5 ultrasonic cleaning transducers they are also multi-frequency transducers and rated 50w each. I was wondering if I can drive these transducer with only a single drive circuit with 300w rating without any issues whatsoever.
Looong answer: Plan the position of the transducers (easier said than done). They should be coupled by the vibration mode of the vessel. Symmetrical arrangement is essential.
I believe it is better to connect the transducers in parallel and watch out the driver for overheating. I doubt you will get full power from the transducers individually but this is an experiment worth trying...
Load on the transducers can decrease the Q and that may increase the power delivered.
The transducers in my possession are multi-frequency 28khz/40khz/122khz. I'm not sure what does these frequency means. Do you think these are resonant frequencies?
Below is a recent discussion about a similar topic. See my post with a schematic of an H-bridge which automatically detects the resonant frequency of a series LCR. It is not guaranteed to match your own project but the principle of operation could be useful.
If you were to drive two or more transducers in series then you must also multiply the supply voltage (possibly to 1 kV or higher). This gets unwieldy. I believe you should drive them in parallel, at a single frequency. If you use a driver for each transducer then they will be out of sync, sometimes sending pulses into the water out of phase with each other.
Like a piezo alarm sounder, the efficiency falls off rapidly beyond the resonant region. How rapidly depends on the transducer's 'Q'. I know crystal oscillators etc may be 'pulled' a bit from their natural frequencies, tweaking their tuning. This is probably not a good idea when you are pumping 40-some Watts into each transducer.
If the transducers are nicely bonded with the cleaning vessel, they will have a rather low Q. You can put all of them in parallel in the feedback loop and the driver will select the optimum frequency automatically and deliver the max power.
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