I intend to get a FX888D, but the cost of the 220v version is holding me back in the meantime. So I have a 220v 40w goot soldering iron which plugs directly into the mains. I have read many have successfully hooked it up to a dimmer switch to lower its heating power. I am trying to attempt this using this dimmer which I have on hand http://www.ebay.com/itm/220V-2000W-Speed-Controller-SCR-Voltage-Regulator-Dimming-Dimmers-Thermostat-/291217415557 But when I lower the voltage only slightly, the iron(not the dimmer) starts to produce a buzzing sound. The lower I go, the louder it gets.
I never kept it long enough for it to heat up as I'm not sure if it would pose a safety risk. Anyone knows why is this happening and if there is a way solve this?
Edit: The dimmer mentioned above takes in live and neutral, and outputs via live and neutral, unlike dimmer switches which use live only.
This is happening because of the dimmer switching on the iron part way through a mains cycle. This causes a sudden inrush of current and causes the wires in the heating element to move appart slightly due to the magnetic field they generate. So lots of clicks rapidly every half cycle will sound like a buzz.
You could try a snubber filter to reduce the sudden rush of current. Or live with it, it is not like it is going to explode are anything.
Phew, ok so I know it's not going to explode I tried placing a 0.1uf cap in series with a 100ohm resistor across the live and neutral of the iron. Is it correct? Because the buzzing is present :~
It is vital that your cap is rated for the mains you have. So in the UK it would be at least 240V AC rating on the cap. Also the resistor has to have enough wattage to take the current.
Is the buzzing any less?
Have you seen this?
With such a light load you might have to up the components a bit.
The buzzing is from an inductor in the dimmer physical vibrating. No snubber on the iron will stop this. In fact, adding capacitance across the iron may make the buzz worse, as the inrush of current is higher as the capacitor charges.
Buzzing in a dimmer may be caused by overloading or running close to its limits, unlikely in this case, or simply by a cheap dimmer.
As stated, the noise results when the triac switches on later in the cycle, causing a spike in current.
You may try soaking the inductor through with epoxy or superglue.
Grumpy_Mike:
It is vital that your cap is rated for the mains you have. So in the UK it would be at least 240V AC rating on the cap. Also the resistor has to have enough wattage to take the current.
With such a light load you might have to up the components a bit.
Indeed, the cap I used is rated at 250v for AC, and a 1W resistor. The buzzing intensity remains the same. I also tried 0.47uf and 220ohm resistor, appears no difference :~
polymorph:
The buzzing is from an inductor in the dimmer physical vibrating.
Sorry if I didn't mentioned clearly in my original post, the buzzing is coming from the soldering iron itself. I am 100% sure as I very clearly hear the sound from it. When I set the dimmer to allow max voltage, the buzz is gone. Only when lowering the voltage the sound is apparent.
polymorph:
What? I think you have some threads cross-connected.
No it is you. There is no inductor in an SCR dimmer. Read the first post, see the link to what he is using.
The other thing you can do is to use a zero crossing SSR and pulse it with an on / off PWM signal but at a time in the seconds region. Due to the long thermal time constant a slow PWM is perfectly acceptable. You can make the PWM controller for the SSR with just a NE555 timer chip.
Actually, there are inductors in a lot of Triac dimmers. They are there to reduce RFI. I was unable to view eBay at work, so I didn't see that this particular one does not.
In any case, it sounds like the heating element itself is vibrating, can't really epoxy that. You could add an inductor to the circuit to slow that sharp rise which is the likely cause of the buzzing.
polymorph:
In any case, it sounds like the heating element itself is vibrating, can't really epoxy that. You could add an inductor to the circuit to slow that sharp rise which is the likely cause of the buzzing.
Sorry... we are not all experts at everything in lif
With a soldering iron heater??
What epoxy can stand that sort of heat!
That is what you said. I don't know why you quoted another thread by someone else. My comment specifically said epoxy the inductor, not the heating element.
It was my mistake in not noticing that he'd specifically said it was the iron, not the dimmer that buzzes. But I never said to epoxy the heating element.
I tried placing a 0.1uf cap in series with a 100ohm resistor across the live and neutral of the iron. Is it correct? Because the buzzing is present :~
