Converting 110V for 220V Appliance and Phase Distribution

[erinspice]

I'm considering purchasing a 220V treadmill, but live in the United States where I will have to use a transformer to convert the 110V to something the treadmill can handle. Do I have to worry about phase distribution differences between my power going in and my appliance, or will the transformer do that? How would that work?

 

[berkeman]

In most areas of the US that I'm familiar with, your service is actually 220V. That's what most clothes driers run off of, for example.

You should have a licensed electrician wire a 220V outlet for the treadmill. The two 110Vrms "Hot" wires that come in from the street are 180 degrees out of phase -- they make 220Vrms differentially, and are used individually with respect to "Neutral" to make the two 110Vrms circuits that are used in the rest of your house.

Since the new outlet is an electrical upgrade (and not just a repair), you will most likely need to get a building permit from your city, and have the work inspected when it is done. That's no big deal, and is meant to protect you and the future owners of the house. If you have a licensed electrician do it, the building permit and inspection are generally included.

 

[erinspice]

Thanks. Yes, we do have 220, but there is only a jack in the laundry room which isn't nearly big enough for a treadmill. I'm trying to get away with not having to put another 220V jack in another part of the house. That would be ugly. Plus, I have a 2 year old and having a 220V jack where she could reach would be more dangerous.

 

[berkeman]

Well, the treadmill that I have at home is 110V, but it requires a well-powered outlet. I guess treadmills take a lot of power.

You could in principle use a 2:1 stepup transformer to provide the 220Vrms for the treadmill, but before you do that, please look at the treadmill's input power specs (or input current, if they rate it that way), and look at the current available on your 110Vrms circuits near where you want the treadmill. The 2:1 transformer will require over twice the treadmill's 220Vrms input current rating, since there will be some heat losses in the transformer. Once you've figured out the size of the transformer required, and figured out if you have enough current available in one of your existing 110V outlets, then you can decide whether you would prefer to have an electrician run a 220V line and install another outlet. You might want to call an electrician in the Yellow Pages to see if you can get a free estimate, or if you would have to pay some for it.

The reason the treadmill is asking for 220V input is to stay efficient in its energy useage. You will be better off from an efficiency standpoint, and also from a balanced load standpoint (concerning unbalancing the load presented to the 220V feed to your house) if you can stay with 220V all the way.

Welcome to the PF, BTW.

 

[erinspice]

Thanks. I'll probably just end up getting a 110V treadmill. It's not as nice, but it sure would be less of a hassle!

 

[NoTime]

Look at the power requirements of what you intend to buy.
Check if it says separate circuit required.

If a treadmill requires 15 to 20 amps at 110v, then you will need a separate circuit installed anyway as there will not be enough power available in the average room circuit to run the treadmill.

A 110v to 220v transformer will require somewhat more than double the current the 220v treadmill requires.
So if the 220v treadmill says 10 amps then the transformer requires about 22 amps. You would not be able to plug this in a standard room wall socket.

220v outlets are often used for large window airconditioning units. They look very similar to a standard 110v wall socket. Not like the 30amp outlets used for dryers in the laundry room.

An electrician should be able to help with appearance and safety concerns.

 

[Panda]

Plus, I have a 2 year old and having a 220V jack where she could reach would be more dangerous.

I have a 6 month old and a house which is fully 240V but there is no danger. 110V can be just as dangerous to a child as 220V and it is more likely to burn your house down so it's swings and roundabouts. Just make sure you take standard child precautions with all electrical outlets.

1. Make sure you use outlets where the live pin is shielded and cannot be access unless a proper connector is put in the socket. This is standard in the UK, and I have seen them used in the US.
2. If your 2 year habitually sticks things in sockets after giving them a good slap (oooppps should say that ;-)) get socket shields which plug into the socket covering up all inlets. These are very common in the UK, I assume you can get them in the US.

 

[Adder_Noir]

Sounds to me like you really will need a new circuit run in. I'd also try and get the transformer fitted as close to your intake as possible because the 110V side of the power will need a very large cable to get the required power to the transformer that the 220V rated treadmill will draw. You don't really want these large cables to have to be run through your house due to cost, disturbance and installation difficulty issues. Better to have the smaller 220V cables run through your premises to your appliance. In the UK we have 240 cables run through our houses as standard. It's only recently the law has even stated that they must be protected by conduit or trunking too. In the past the accepted method was just to clip them to the wall.

Also bear in mind your transformer will not be 100% efficient. Which will further increase the cable size needed.