With 120 Vac connected to the outside pins as intended, the center pin will have approx 60 Vac with respect to whichever outside pin is the neutral. BUT, this voltage will be at an extremely high source impedance because the internal contact surface area is so much smaller than the outside pins with their "electrodes". If you clip and filter this, you will have a DC level that can drive a MOSFET that can drive a DC relay coil if you have a DC voltage source referenced to the AC neutral. Or, two MOSFETS back-to-back and no filter to drive an AC relay coil.

ak

 

Well if cool with the mods I would start along the lines which AnalogKid suggest. Measure off the sensor to AC neutral and see what you get. Then rectify it and see how that goes. As mentioned it will be a high impedance source. If you can get a good repeating DC voltage after full wave rectification I would divide it if necessary and use it to drive a MOSFET within the rated voltage and have your MOSFET control a relay.

Ron

 

I am amazed such things are legal. I suppose its big advantage is that if it runs out of water while switched on, nothing bad will happen - no water, no heating.

How so, specifically. That basic setup is routine for cheap commercial warm humidifiers - no?

 

How so, specifically. That basic setup is routine for cheap commercial warm humidifiers - no?

Yes. Since the steam generator is enclosed in the overall housing it really doesn't prevent much of a hazard. Yes, also simple and inexpensive or "cheap". It does make steam and in turn increase humidity but hardly high end.

Ron.

 

Yes. Since the steam generator is enclosed in the overall housing it really doesn't prevent much of a hazard. Yes, also simple and inexpensive or "cheap". It does make steam and in turn increase humidity but hardly high end.

Ron.

The water going in and out is going to be live.

 

We have no Idea what the poster is makinging there a steam cleaner that uses this same setup to make steam for cleaning and it's hot enough to burn you bad. I'm just pointing out to be careful the things you think will not hurt you get you faster then anything.

 

I never heard whether he was heating the water or not. I thought it was just level.

 

The water going in and out is going to be live.

I think that is a yes and no. Once the steam leaves the chamber no big deal. I am not sure how the controller PCB handles the drain and fill as to the solenoid when the electrodes are active? The assembly itself is not intended for "stand alone" operation. It has a mating control board. While I have no doubt the thing can be designed around it is also a device which takes advantage of the conductivity of tap water to function. Whatever gets done with the thing will require some thought to preclude certain things happening when they should not happen.

Ron

 

With 120 Vac connected to the outside pins as intended, the center pin will have approx 60 Vac with respect to whichever outside pin is the neutral. BUT, this voltage will be at an extremely high source impedance because the internal contact surface area is so much smaller than the outside pins with their "electrodes".

I don't think it will be such "high impedance." I have done several tests over the years of electricity through water, and found that not much exposed electrode surface area is required to conduct significant current, with average tap water. With heavily salted or brine water, just a few mm of solid copper wire or lead solder can conduct several amps!

 

I don't think it will be such "high impedance." I have done several tests over the years of electricity through water, and found that not much exposed electrode surface area is required to conduct significant current, with average tap water. With heavily salted or brine water, just a few mm of solid copper wire or lead solder can conduct several amps!

With the unit that I linked, when asking about the basic electrode boiler methodology, they note that if steam does not start in 10 min, add a "pinch of salt" (one time only). Also, in troubleshooting when there is too much steam, they recommend that you dilute the tap water with distilled water. This is entirely consistent with what you are saying.

 

I have done several tests over the years of electricity through water,

One actual test result is worth a dozen theories.

 

One actual test result is worth a dozen theories.

With water yes, with large buttons, maybe not so much

 

With the unit that I linked, when asking about the basic electrode boiler methodology, they note that if steam does not start in 10 min, add a "pinch of salt" (one time only). Also, in troubleshooting when there is too much steam, they recommend that you dilute the tap water with distilled water. This is entirely consistent with what you are saying.

Yes conductivity is highly dependent on Total Dissolved Solids. Most tap water is sufficiently "dirty" to be a good conductor.

 

Yes conductivity is highly dependent on Total Dissolved Solids. Most tap water is sufficiently "dirty" to be a good conductor.

Did you get much hydrogen (bubbling) as you heated with 120vAC from electrolysis?

 

Did you get much hydrogen (bubbling) as you heated with 120vAC from electrolysis?

Haha, until this thread I would have never dreamed of applying mains voltage to water (although now I'm unhealthily curious). I was using a 0-30V/4A variable power supply. I don't remember what kind of bubbling I got off straight tap water. But I know that if you throw a few TBSP of salt into a gallon of water, the P/S will go into current limiting around 10V, and yeah, it will give you a spectacular show of hydrogen bubbles. Enough bubbles to light on fire for added excitement. If you're after just hydrogen though, AC isn't the way to go.

 

Haha, until this thread I would have never dreamed of applying mains voltage to water (although now I'm unhealthily curious). I was using a 0-30V/4A variable power supply. I don't remember what kind of bubbling I got off straight tap water. But I know that if you throw a few TBSP of salt into a gallon of water, the P/S will go into current limiting around 10V, and yeah, it will give you a spectacular show of hydrogen bubbles. Enough bubbles to light on fire for added excitement. If you're after just hydrogen though, AC isn't the way to go.

I'm not looking for hydrogen, I'm wondering how the AprilAire model 60 tank in a model 600 humidifier doesn't generate tons of hydrogen at 120VAC.

 

I'm not looking for hydrogen, I'm wondering how the AprilAire model 60 tank in a model 600 humidifier doesn't generate tons of hydrogen at 120VAC.

yeah good question. that seems like it would be a problem.

 

I'm not looking for hydrogen, I'm wondering how the AprilAire model 60 tank in a model 600 humidifier doesn't generate tons of hydrogen at 120VAC.

maybe it isn't explosive when in an atmosphere of steam.

 

Haha, until this thread I would have never dreamed of applying mains voltage to water (although now I'm unhealthily curious). I was using a 0-30V/4A variable power supply. I don't remember what kind of bubbling I got off straight tap water. But I know that if you throw a few TBSP of salt into a gallon of water, the P/S will go into current limiting around 10V, and yeah, it will give you a spectacular show of hydrogen bubbles. Enough bubbles to light on fire for added excitement. If you're after just hydrogen though, AC isn't the way to go.

Also, chlorine gas (Cl2) and sodium hydroxide are the products of electrolysis of salt water. You need more inert ions to make hydrogen. Sulfuric acid or baking soda both work well.

 

maybe it isn't explosive when in an atmosphere of steam.

Not really explosive - more like flammable. Also, diluting it with something besides oxygen is good.