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Thread Number: 38506
/ Tag: Brand New Vacuum Cleaners
using a transformer to use a 240 volt central vacuum on a 120 volt outlet |
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| Post# 409562 , Reply# 1 5/18/2019 at 16:03 (1,797 days old) by vacuumdevil (Vacuum Hell ) | ||
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| Post# 409563 , Reply# 2 5/18/2019 at 17:08 (1,797 days old) by constellation86 (Roy, UT) | ||
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Short answer is no. The reason some central vacuums use 240 volts is that household 120 volt outlets can not deliver enough wattage. The maximum wattage a 120 volt 15 amp outlet is 1800. If you are lucky drawing more than this will trip the breaker if not it could start a fire. | ||
| Post# 409568 , Reply# 4 5/19/2019 at 01:19 (1,797 days old) by MadMan (Chicago, IL, USA) | ||
Does your apartment have a 240v stove/range outlet? Or an electric dryer outlet? Because those would be my go-to. Failing that, one of those transformers is an option.
However, as already said, you're only gonna get 1800W out of a typical 15A circuit, and that's assuming NOTHING else on that circuit is drawing juice. If you overload it and trip the breaker, you trip the breaker. That's what they're there for. There's no more fire hazard than there is normally (ie, old building with old wiring), so don't worry about that. Possible problem #2, you're looking at American to European step-up transformers. The rest of the world (foolishly) chose to use 50Hz instead of 60. I can't find any info on those converters as to frequency. I'm *assuming* it's just a giant transformer inside, which would output the same Hz as is input. Which would be good for your purposes of using 240v American appliances. But if by some chance it was a digital converter, it might output 50Hz, which would not work with most central vacs, as they usually have induction motors (which depend upon the correct frequency). Now the real question is what is the amp or watt rating of the 240v appliance you're thinking of using? Remember that Watts = Volts * Amps, so 7.5A * 240v = 1800w = 15A * 120v. Basically watt rating is independent of voltage. Oh also. If you're clever, and I feel like I saw this mentioned in another thread not long ago, you can find two outlets on separate phases in your apartment, and with a little ingenuity (and a trip to the hardware store) you can wire up a 240v outlet. Basically, half the circuits in your place are on one phase, and the other half are on the other. Two phases together make a whole 240v circuit. However, I wouldn't hardwire anything like that, but as a temporary thing, like an 'extension cord' that you unplugged when you finished using it, would be fine. Then, in theory, using two 15A circuits, you could create a 15A @ 240v circuit. Again, with no other loads. Actually, this would probably be easier, cheaper, and even safer than using a converter. Because, again, a converter puts the whole load on one breaker, and would then be limited to half the current draw as the other way. Speaking of wiring, at least the first converter uses a universal outlet for the output, which would support using a normal US 120v plug. I'm fairly certain most central vac units would not even have a plug, being hardwired. But that's easily wired to a cord and plug. When you start getting into stuff like using a 120v plug for a 240v appliance, I would really make sure you label everything, so nobody does anything stupid. Not that plugging a 240v motor into 120v would do much. You know what you need to do? You need to find the breaker box for your apartment and look inside it. Maybe snap a pic for us. Sometimes the handwritten labels would tell you enough. ie, one of them says 'dryer' or 'stove.' But yeah, definitely also let us know the power ratings of the stuff you wanna use too. | ||
Post# 409577 , Reply# 6 5/19/2019 at 08:47 (1,797 days old) by n0oxy  (Saint Louis Missouri, United States) |
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the transformer may not work According to the specs, the voltage is 240 and the amp rating is 15.50, I'm thinking it would overload a regular outlet, I just wonder what kind of plug it uses, unless it's designed to be hard wired, I will include a link to the unit itself. Mike CLICK HERE TO GO TO n0oxy's LINK | ||
| Post# 409578 , Reply# 7 5/19/2019 at 10:44 (1,796 days old) by sptyks (Skowhegan, Maine) | ||
Actually... A transformer with no load attached draws very little current. I found this statement on Wikipedia:
"Since the secondary of the transformer is open, the primary draws only no-load current, which will have some copper loss. ... Since no current passes through the secondary windings, no magnetic field is created, which means zero current is induced on the primary side."
Therefore since the current rating of the central vacuum you want to connect to the transformer is 15.5 amps @240volts and since the total amperage drawn on a 120 volt circuit would be approx. double what is stated on the vacuum's information plate. In this case: The central vac is rated 15.5 amps@240 volts, then the total amps drawn from your 120 volt outlet would be slightly more than 31 amps@120 volts which will prohibit usage of a step-up transformer in this case.
The only way to go in this case would be to connect it in parallel to your electric stove's 240 volt outlet.
This post was last edited 05/19/2019 at 11:05 | ||
| Post# 409581 , Reply# 8 5/19/2019 at 16:49 (1,796 days old) by MadMan (Chicago, IL, USA) | ||
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tolivac - 480/277v is for industrial use and big buildings, no apartment building is going to get that (unless it's a huge building, and even then, there would be a secondary transformer or something to provide normal 120/240 to each apartment). Also residential consumers almost never get 3 phase power. And even if they did, the circuits for the normal house stuff would still be on 2 phase. In other words, no residence is going to have access to 277v.
n0oxy - Nevermind the plug, you can always change it. But yeah, 15.5A at 240v is 31A at 120v, so it's not happening with the transformer thingy. However, using the two-outlet system I described, you *might* get away with it. Because the amp rating is a maximum rating, and typically describes the current draw at startup. So you might yet get away with using two totally unloaded circuits, and say, make sure the hose is open to suck air in during startup. Still, that's a maybe. Where's the pic of your breaker box? | ||
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Post# 409582 , Reply# 9 5/19/2019 at 17:10 (1,796 days old) by bagintheback (Flagstaff, Arizona) |
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Probably not a good idea
Check to see how much amperage you can draw on the circuit first; most are 20-30 amps. 30amps*120volts is only 3,600 watts, so 5000 will not work even if nothing else is connected to the circuit.
I'm installing a NEMA-30 in my garage to charge an electric car soon. We've been pulling >12amps from a standard 120 outlet and the outlet is starting to look burnt. The cord feels like it could melt soon. So from personal experience, limit any load to 12amps max per outlet. Like others mentioned, it's not worth risking a fire over. | ||
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Post# 409607 , Reply# 13 5/20/2019 at 18:46 (1,795 days old) by n0oxy (Saint Louis Missouri, United States) |
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another option I think this is similar to what I linked to in my previous post, I just wonder if those central vacuum units have a 15 or 20 amp plug. Mike CLICK HERE TO GO TO n0oxy's LINK | ||
| Post# 409617 , Reply# 14 5/21/2019 at 01:45 (1,795 days old) by MadMan (Chicago, IL, USA) | ||
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n0oxy - Stop worrying about the plug. Plugs can be changed to whatever you want and won't cost you more than $5 and a trip to home depot. It's the least of your concerns.
Now, that thing that they want $200+ for is exactly what I described in my previous post. You could make that yourself for $50 or less. It's just two extension cords wired into a box with an outlet on it, nothing else is needed. Maybe scroll up and actually read my comments about it? >_> | ||
| Post# 409661 , Reply# 16 5/21/2019 at 23:54 (1,794 days old) by MadMan (Chicago, IL, USA) | ||
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If you pay your own electric bill and have your own meter and breaker box, there's a 99% chance you have 2 phases in your apt. However if you're on old-fashioned fuses, there is a possibility you've only got one phase, mostly depending on the age of the fuse box, but it would have to be ancient.
Also, I don't know the severity of your impairment, but you could always ask someone to assist you with - at minimum - replacing the plug on the central vac. :/ | ||
| Post# 409667 , Reply# 17 5/22/2019 at 09:29 (1,794 days old) by Blackheart (North Dakota) | ||
Twin turbo | ||
| Post# 409693 , Reply# 20 5/22/2019 at 21:38 (1,793 days old) by MadMan (Chicago, IL, USA) | ||
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First off, remember that ordinarily there is a paired breaker (two breakers that have their levers connected with a bar across them) on the absolute top, usually separated from the rest of them - that one is the main breaker for everything. Anything that's 240v, like the air conditioner, will also have a paired breaker, probably that's the big one you're referring to.
Three breakers for a 2 bed 1 bath apartment isn't that far fetched. Of course that does kind of mean that if you wanted to use the two circuit method, you would need to unplug or turn off just about everything in your apartment to use the central vac. The good news is that if you have the central air running from your breaker box, which is very likely, you have 240v available. So there's that. | ||
| Post# 409715 , Reply# 22 5/23/2019 at 22:30 (1,792 days old) by MadMan (Chicago, IL, USA) | ||
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First off, if you have ANYTHING 240v running off of your breaker box (like central air) you automatically know for sure that you have the 2 phases.
Second, when you say 'large breaker' do you mean a double or paired breaker? One which is two breakers that have their switch levers connected with a bar across them? It should seem like two separate breakers with one very wide lever. Now the single outlet you say is on the 'large breaker' in the dining room, would that outlet happen to be under the windows? If so, there's a very good chance that was originally meant to be a 240v outlet for a window air conditioner on a dedicated circuit. If it is indeed on a paired breaker, all by itself, that hints that it likely still has the wiring in the wall for 240v. It would be a simple matter for someone with electrical skills to wire it back to being a 240v outlet, and that would solve your problems. Even if it is a 15 amp circuit, it would probably manage the central vac without tripping the breaker. And you could have the breaker changed to a 20 amp one, provided the wires feeding the outlet are big enough. Then you could just hook up a very long cord to the central vac unit you want, and plug it into the dining room outlet whenever it's cleaning time. | ||
| Post# 409716 , Reply# 23 5/23/2019 at 22:32 (1,792 days old) by MadMan (Chicago, IL, USA) | ||
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| Post# 409738 , Reply# 26 5/24/2019 at 13:17 (1,791 days old) by luxflairguy (Wilmington, NC) | ||
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Mike! Don't run a-foul of your landlord or management company on this! Check with them first! Greg | ||
| Post# 409755 , Reply# 27 5/24/2019 at 22:03 (1,791 days old) by MadMan (Chicago, IL, USA) | ||
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Mike, if the outlet in the dining room is under the windows I can almost guarantee that it was once a 240v outlet. In that case, rewiring it to be 240v again is a simple affair, perhaps a 5 minute job, would be equally as safe and effective a solution as running a whole new line, and shouldn't cost you much at all.
However, I'm still betting that you do have an outlet for an electric dryer or stove, given those apparently unused large breakers you described. Checking behind the stove wouldn't be a bad idea. Having an electrician visit your home, or at least someone moderately familiar with electrical work, would also be a good idea. Describe your situation to them and mention all I've said here. | ||
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Post# 409789 , Reply# 29 5/26/2019 at 00:23 (1,790 days old) by tolivac (Greenville,NC) |
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Was the dining room outlet used to run a 240V AC unit at one time-from another resident that lived in that apt? | ||
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Post# 409890 , Reply# 30 5/28/2019 at 21:16 (1,787 days old) by n0oxy (Saint Louis Missouri, United States) |
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having an outlet installed I'm not sure whether it was ever used for a window air conditioner, but my landlord said that if I want to have a 240 volt outlet installed it's fine with her. Mike | ||
| Post# 409897 , Reply# 31 5/29/2019 at 00:25 (1,787 days old) by MadMan (Chicago, IL, USA) | ||
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Post# 409924 , Reply# 32 5/29/2019 at 21:03 (1,786 days old) by n0oxy (Saint Louis Missouri, United States) |
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outlet I looked behind the stove, there is nothing there, my stove is gas. I think I have decided which company here I will ask to see if it's possible to have an outlet installed, and the first thing I'm going to ask them to check is that outlet in the dining room. As you said, why install an entire new circuit if we don't have to? Mike | ||
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Post# 411098 , Reply# 33 7/2/2019 at 11:43 (1,752 days old) by n0oxy (Saint Louis Missouri, United States) |
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update So, I'm hoping to get my 240 volt outlet installed July 31, if it's possible. Really excited, then I can get some 240 volt super duper central vacuum beasts. Mike | ||
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Post# 412480 , Reply# 38 8/7/2019 at 08:39 (1,717 days old) by n0oxy (Saint Louis Missouri, United States) |
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got my Drainvac Twin Turbo Got my first 240 volt central vacuum unit yesterday, in a word it's awesome. The outlet I had installed definitely works, I plan on testing it with the quick 220 volt power supply tonight. What a beast! | ||
| Post# 412490 , Reply# 39 8/7/2019 at 11:56 (1,716 days old) by MadMan (Chicago, IL, USA) | ||
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| Post# 412533 , Reply# 41 8/9/2019 at 00:44 (1,715 days old) by MadMan (Chicago, IL, USA) | ||
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Dude, tons, TONS of older apartments and houses have added-on dedicated outlets for window air conditioners. It's extremely common, especially in Chicago, a place that's temperate with hot summers. And especially on buildings that have been fitted with central air conditioning, those outlets are almost always converted to 120 volts since they are no longer needed. The fact that it was below the window in a main room like the dining room, and since you also said it was on its own breaker, it was a dead giveaway.
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