Two 110V Appliances in Series Running Off 230V?

If the 220V is from one line to earth, you are right that some insulation might be insufficient. But if the 220 is +110/-110, it would not be a problem. The resistance/impedance of the two machines would need to be equal in order to divide the voltage equally.

Yeah the 230V is to earth-ish, not split +/- 110V.

Has anyone tried something similar? I would give it a go, but the smoke machines aren't mine to blow...

Yesz. Are the machines with glycol or with CO2 in solid form? Is there electronics

in it or just thermostats and switches?

I read they have displays e.g. The 50/60 Hz difference should not be the problem, for a short time. If any electronics in it just use a transformer.

Probably you meant: my US iron gets EU power this way?

These gadgets also produce birth defects by pregnant women. Glycerol burning - shame!

the difference in frequency will eventually fry any electronics.

It would be a good idea to put a megger meter on the machines to check the insulation before offering their remains to any deity.

I wonder... when the first machine stops running will it isolate supply to the second?

So the insulation on circuits designed for 110V w.r.t. earth is to be stressed to 230V w.r.t. earth? What happens when something can't take it? Will all CR4 users be standing >10m away when it goes BANG?

They're Glycerol smoke machines, and I do think they have some more electronics in besides a simple thermostat.

I think I'm going to end up with a partial open circuit as rakesh_semwal mentioned, which will indeed destroy that machine. So I'd probably end up with more smoke than I wanted...

I could possibly get around it by opening them up and running both off one set of electronics or something, but I'm not going to bother.

I can't see how I'd end up with a closed circuit on any appliance? Would this not just blow the main fuse if any appliance did that?

Mind you I had a few questions from your replies:

Is the different in frequency bad for electronics? How would I go about using a high power diode to solve this? I did a quick google and couldn't find any obvious info.

Finally, I have no idea what the testing required on electrical goods are, but do they run different insulation tests for 110V / 230V items (as opposed to just testing everything to 500V)? Is is quite likely that 110V circuits will short when charged to 230V?

Thanks for your replies anyway!

Is the different in frequency bad for electronics?

Yes. In my less competent days I detroyed sound equipment by dodgying-up a genset to supply correct voltage but incorrect frequency.

How would I go about using a high power diode to solve this? I don't know.

do they run different insulation tests for 110V / 230V items (as opposed to just testing everything to 500V)?

Yes. Insulation testing is done at double operating voltage.

Is is quite likely that 110V circuits will short when charged to 230V?

Likely? don't know. Possible? Yes.

NO, you've already answered why in general it's a bad idea.

Putting two "anything" in series assumes that the two units are identical so you'd get half voltage across each one. In practice, even with no heaters switching, there will be a difference so one will get a higher voltage. (The difference could even be just the differing starting characteristics of the motors).

NONE OF THE ABOVE.

I assumed the worst case, US made 110V gizmos powered from European true 220V. The true 220V can be reduced - rudely - by diodes cutting off half of the wave. Cheap travel converters for hair dryer use do that exactly. The power range is right, the price is right (cheap). Electronic displays draw so little power, their power supplies are normally way oversized, no problem. Test it out.

One such converter for each. No interaction, no problem. Not a beautiful solution, but works. Insulation testing is 1200V -2500V depending on class, ok.

Having read your post with interest, and followed your logic... it is a bad idea on so many levels.

Smoke machines... not something you use in your lounge, maybe in a night club or for a mobile disco???

Apart for the danger/safety aspect of ramming 240 volts into a units designed for 110 volts, and the fire risk to not only the equipment, there is the public safety angle.... please think about that.

I would suggest that find a "Yellow" 240/110v transformer FOR EACH MACHINE, the type used on building/construction sites. Safe, yes heavy, but will do what you want and answer all your problems and worries.

One other thing.. assumption is the "mother of ALL screw-up's".. please read the nameplate on the equipment, don't assume that its 60Hz.. read the label. And if you do connect these two machines to 240v then they will make smoke, but not how you expect them too!

You. are wrong, obviously. If I cut off half of 220V, I get a 110V with a crude waveshape. What part of it is difficult to grasp???

I'm wrong?

which part EXACTLY is wrong?

If the OP was talking about light bulbs. then yes.. but he's not!

what the OP is proposing is downright dangerous.. now which part of that don't YOU grasp?

Or could it be you re looking for an argument.. if so, go stand in front of a mirror, there's a good boy!

NO, I am not picking anything. When you put a diode in the path of a AC waveform, it cuts off the current, when one half of the wave occurs. Capiche?

The remainder is a not so nicely formed half voltage. Capiche?

Any heater or light is happy with that. Capiche?

Any power supply with plenty of reserves is happy with that. Capiche?

And I will stop with the Capiche, when you Capiche it, and behave as a normal human.

Where were diodes previously mentioned? Or partial wave-forms?

"Capiche" is not spelled correctly.

Brich is largely correct, so why did you insult him with this repeated "capiche" shtick?

Hello again. wondered how long it would take....

Question where is this diode you like to talk about?

I understand a lot of things.. but sadly not what you are trying to say...

However it does tell me you have no real practical experience, and would not last in the real world, as you would do yourself a mischief, or worse..

Now as this forum is to offer advice, then please if you have something of importance and is of use to the general topic then I'm all ears and while I admit, and have done on many occasion, I don't know it all, I alway like to learn and like to debate a point.

So stop with the "do you understand " in your poor Italian, go back to your reply to me and say "I don't agree with you because....."

So shall we try again.. only this time be nice.. there's a good boy!

Allrigt. I try again. You are a nice guy.

A series diode cuts off the current in a half wave. The result is a mangled half voltage waveform, nonetheless, half power.

Since, that is your aim, plug them in, and be happy.

Allright??

sorry, your latest statement make no sense whatsoever.. unless someone can explain it to me other than you!!

What diode?

And another questions.... is English your first language?

Were you intending to reply to me? Where I said (further down):

"Although by cutting off half the wave, it will have the effective voltage in terms of power, but peak voltage will still be twice as high (1.41*230 compared to 1.41*110). Thus this doesn't solve insulation issues."

Tim..

methinks you'll not get an answer, the only real way of getting 110volt is to use a transformer to reduce the voltage.

I think our friend, (loosely used term) is somewhat aggressive, going on his past posts, and will start an argument in an empty room.

I'm sure it has annoyed him with the comments informing you its not a good idea, in the humble opinion of the many, to connect your units in series, whereas he feels he has the answer to your problem, all be it a theoretical one.

Be safe, as I'm sure you will be! unlike someone else that springs to mind!

Thanks for the replies. I probably wasn't clear enough in my last post when I said I'm not going to go ahead with it.

However the idea still raises some questions that I have. And will educate me!

@Chook, just regarding yours and leveles answers on insulation tests, they are conflicting. This is probably due to different standards, but I was just hoping you could confirm that some appliances are indeed only tested to twice rated voltage?

@JRaef, I was expecting a normal shutdown, and if it was indeed a true open circuit I see no problem with this other than both machines shutting down at the same time. My concern is that one machine may simply isolate the heater element for example, frying the rest of the electronics in that machine due to the unbalanced resistance. This is why I'm not going ahead. With regards to using 50Hz on a 60Hz motor, I mentioned I'd not be running these at full load, thus eliminating the overheating issue that could occur.

Secondly you mention short-circuit, as did rakesh_semwal earlier. I don't see how any appliance would ever have a designed short-circuit??

@leveles, ah thanks for explaining how a diode could be used, it puzzled me for a bit. Although by cutting off half the wave, it will have the effective voltage in terms of power, but peak voltage will still be twice as high (1.41*230 compared to 1.41*110). Thus this doesn't solve insulation issues. I'm guessing you were aware of this as you mention insulation testing is done to 1200V+, is this true of (most) appliances?

@brich, at the risk of sounding defensive... I assumed 60Hz as firstly this is common for 110V appliances, secondly, and more importantly, this is the worse case scenario. My mains power is 50Hz. If the machine was 50Hz it would only work better / more safely. Also I was never intending of using these in a public setting. A transformer would be a worthy investment if that was the case.

I do not have access to the standards for the next 10 days (sorry for that, but not sorry for being on a somewhat ill-defined holiday) but I am reasonably sure that Australian Standards for appliance testing specifies double operating voltage for insulation testing - AS/NZS 3760: In-Service Safety Inspection and Testing of Electrical Equipment (AS = Australian Standard, NZS = New Zealand Standard). So single phase appliances and equipment are "meggered" at 500 Volts, and three phase equipment at 1000 Volts.

Thanks for that info!

I looked into it a bit more and did see it say 500V & 1000V depending on the phase. Something I found interesting is that apparently a basic Megger test will not satisfy the 3760 standard because some switches will only turn close when the appliance is on, so the Megger test isn't really testing the whole appliance. This make sense.

However, apparently a PAT tester is used, which powers on the appliance and then tests for leakage current to determine resistance at the rated voltage. This seems flawed as from my understanding because: internally a live wire may be too close to a grounded part of the appliance (surely this is the main reason for insulation tests?), but just far enough that the air doesn't reach breakdown voltage at 230V, however it would if the wire moves a tiny amount. The PAT test will still measure a very high resistance, but one slight bump will cause the appliance to fail dangerously. A Megger test would have picked this up.

Hmmm getting a bit side tracked here. I might leave it at that for questions.

The switches are designed to interrupt 110v. If you ask them to deal with 230v you'll have some very unhappy switches.

In USA, Residential power is generally supplied by 2-phase (220V) and a neutral will be provided from midpoint tap of the same two phases of a three phase Delta connected winding.

This makes supply voltage as

• 1. Two Phases as 220V
• 2. Neutral Voltage is obtained by between Midpoint tap of two adjacent phases is 110Volt(Exactly half Voltage) and midpoint will not move much as in the case of Y-connected Neutral due to difference loading of currents in phases..
• 3. Frequency is 60Hz

This kind of power supply is mostly available in USA. As they do not give important to cost but system.

If your system is 230V & 50Hz, then theoretically you may connect two machines of 110V in series but practically you will face the followings:

1. 1. Two machines subjected to over voltage. 230v can have voltage fluctuation of +5% to-5% from the Electricity supplying Co. The System voltage will be maximum at+5% that is 230x (1.05)=241.5V. Assuming they share equally 241.5volt. Each machine is subjected to 9.77 %( 0.5x (241.5-220) x100/110) higher voltage than it is rated.
2. Second problem is the frequency 50Hz. By connecting 60Hz motor to 50Hz power supply, speed of the fan motor will be less. Hence the speed of the fan motor will be (50x100/60) %=83.33% only. This less speed of the fan will not be sufficient to remove the heat generated inside the machine thereby overheating will take place and damages the electronic circuit inside the machine.

Therefore never try to connect the machine to electrical supply other than its rated voltage and frequency.

Mushtaq Hussain-India