I was disassembling a fan to reverse engineer its electronic humidity control and experimentally put some capacitors in series with the fan to slow it down.
No series cap 242V 14.5W 90mA (0.66PF)
220nF the fan struggled to turn - 95V 1.5W 22mA (0.27PF)
470nF the fan ran at about 1/3rd the power - 157V 5.5W 51mA (0.43PF)
1uF the fan ran at SUPER TURBO POWER! - 300V! 24W 120mA (0.8PF)
I'm guessing I may have hit a perfect inductor/capacitor combo to result in such a dramatic result by somehow creating a phase shift that added to the supply voltage.
It's not something I've come across before, and makes me realise that in the wrong situation this could cause weird problems with equipment.
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No series cap 242V 14.5W 90mA (0.66PF)
220nF the fan struggled to turn - 95V 1.5W 22mA (0.27PF)
470nF the fan ran at about 1/3rd the power - 157V 5.5W 51mA (0.43PF)
1uF the fan ran at SUPER TURBO POWER! - 300V! 24W 120mA (0.8PF)
I'm guessing I may have hit a perfect inductor/capacitor combo to result in such a dramatic result by somehow creating a phase shift that added to the supply voltage.
It's not something I've come across before, and makes me realise that in the wrong situation this could cause weird problems with equipment.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- https://www.bigclive.com/coffee.htm
This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators
I Was experimenting with this fan and found an interesting thing. The reason I had the fan was to take the humidity Center out of it and just reverse engineer it. But watch this. I've got the fan connected to the hoppy and I'm going to plug the hop in and this meter is showing the voltage across the fan.
but I've got a capacitor here and it's not in circuit yet so let's take a look at the fan before we add the capacitor. It's going to get noisy. sorry, you're going to get lots of pushing noises. There's a fan so it comes up to speed and it settles down at 89 milliamps and 14.5 Watts Okay, it's showing Mains Voltrast at 241 roughly.
so that's 88 milliamps, 290 milliamps, and 14 and a half. Watts Watch this. I'll unplug it making sure I don't put my fingers intent in the process, move the capacitor. the capacitor is now in series with it and the meter is still measuring the voltage across the fan.
and I plug it in now and all. Hell, let's loose. Super Turbo Uh 24 Watts From 14, it's up to 240 milliamps and it's showing 305 volts across the phone. I shall unplug it because the phone will not be happy at that.
So the fact that this capacitor is here in series with an inductive load it must be the there must be something happening that is effectively causing a phase shift that is somehow boosting the voltage. and I can't quite get my head around that. If you have any thoughts on that, let me know in the comments down below.
What capacitor should I use to reduce the power by 50%
If you want to investigate further and get a good idea of what's going on, the instrument for that is the scope. Preferably one that's at least got two channels. And i strongly suggest that the fan (or the hopi) be plugged into an isolation transformer!
This does work, tried it.
Just make sure to put a bleeder resistor parallel to the capacitor if you use this regularly.
Hook this up to a smart meter , letโs see if the smart meter records more power used with the cap ?
It will depend on the amount of capacitance added. The most reasonable explanation is resonance. Perhaps the capacitance was just right to resonate with the inductance of the motor at 50 Hz (from the plug and 240V I assume this in in UK). Try to add another capacitor, it might go even faster or slower depending on the exact inductance and its corresponding impedance…
and would this work on any fan? I'm assuming AC only and not DC
Serial resonance, thats why we don't compensate PF to 1 but 0.98 or close
If it is working with PWM, is not it normal when you place a capacitor which extends the width of pulse, so the current, so the speed?
I just tried that… interesting. Old gutted space-heater that I'm using as a fan in a small window to suck air out of the basement to keep air circulating. About 11W and 0.74 power-factor before. 1uF cap did nothing, and the fan wouldn't even start moving. Ordered a 10uF "starter" cap, woohoo! Zipped up to about 20W and 0.90 power-factor. If I throw on maybe another coupla uF I might get even more. Tempted to get another starter cap for 20uF total and see what happens. As long as the voltage above the cap doesn't exceed 400V, I'm gold.
someone tag ElectroBoom
Inductor + Capacitor = Resonance
Circuit got closer to rezonance
angle between current and voltage
Now let's see if electroboom make this experiment go BOOM
that called resonance
You need electroBoom to answer this
I Thought it was crazy that this fan was using 14 watts (normally), but then i did research and found out that fans use more a lot more power than I expected.
I'm curious why your country is using 240V. Instead of 120V. Why would they not split The phase. In the breaker. And distribute one twenty throughout your house. I don't know, it just seems a lot safer. To use a lower voltage in residential areas.