Can American (120v 60hz) electronics, power tools run on 100v 60hz (Japan)?

[TheNiceGuy]

I'm looking at importing some stuff to use here in Japan. For example, a Bosch 1000w rotary hammer drill. Will the lower voltage have any real-world effect?

 

[dave_the_nerd]

In the case of the hammer drill or most power tools? Yes - an AC motor designed for, say, 115v AC will lose about 20% of its peak power running on 100v. (Rough math - I just remember something about it being a square of the voltage, and not linear with the voltage.) Most consumer electronics use AC/DC converters and can input pretty much anything. (A typical laptop charger accepts 100-240v, 50-60Hz.)

Most tourists don't really notice the different and will tell you that you don't need a converter because their laptop and electric razor worked fine. But if you're running power tools you'll probably want a step-up/down transformer. Make sure you get one that's rated (wattage) for the tools you'll be plugging into it.

 

[TheNiceGuy]

Wow 20% sounds like a lot. A reliable Transformer capable of running 1000+ Watts is pretty expensive, and may be a pain the ass.

 

[dave_the_nerd]

Wow 20% sounds like a lot. A reliable Transformer capable of running 1000+ Watts is pretty expensive, and may be a pain the ass.

There's a lot of math.

http://aceee.org/files/proceedings/2001/data/papers/SS01_Panel2_Paper27.pdf

But as near as I can decipher, you'd probably see a noticeable ding in the awesomeness of the tools.

If you don't want to get a transformer (and, FYI, my blender is a 1500w unit, so...) is there a problem with the tools available locally? It's not like nobody Japan makes stuff - there's gotta be tools designed for local power, right?

Or are you only there for a little while?

 

[TheNiceGuy]

Thanks. Someone mentioned that real-life house US power actually can fluctuate down to 100 V, and appliances are made to account for that. Is that true? That would be ideal if I could just use the tool as is. The linked Transformers had very mixed reviews, it sounds like they're easy to break and you need double the rated how are you going to be using. I haven't priced out proper transformers, but I imagine they are outrageously expensive.
The selection of local tools is limited, and they are always more expensive than the American counterparts. Often even when you add the cost of shipping and duty. In some cases they're not available at all.
For example, I want to buy this model:
http://www.amazon.com/gp/aw/d/B000B...=_SL500_SR100,64_&refRID=0VPTZ81NWNW66ADA9T89
The closest thing available here is an older weeker model lacking some features and it's more expensive. The US one even throws in a free grinder while they're at it.
https://www.amazon.co.jp/gp/aw/d/B0...=_SL500_SR100,75_&refRID=XXZ5TF38RB4832CT7T9Y

There must be a backstory, as it gets a bit weird. For example there's a lot of Japanese brand tools being sold in the States that you can't buy in Japan. There's also some locally made tools that you can't buy elsewhere. For example, someone is importing these reconditioned Hitachi air nailers from the states , Changing the fitting size to fit the local coupler, and selling them for more than you can buy them you in the states. The cost/selection gap is so big, I'm actually gonna buy one of these.

 

[PowerEngineer]

What Dave has said is correct. The amount of real power that can be delivered to a load goes up/down as the square of the voltage. On that basis, a voltage drop from 120 volts to 100 volts lowers the delivered power by 30%.

Yes, it's true that the voltage you actually get at a socket can vary over a range from 100 - 120 volts; it's (mostly) affected by how much demand is being placed on the feeder that you and your neighbors are sharing. The higher the loads, the higher the currents, and the greater the voltage drop from what's at the substation. There are control schemes for tap changers and shunt capacitors that help keep voltages reasonably close to 115 volt target, but it's inexact. People nearer the substation will generally have higher voltages than those connected towards the ends of a feeder.

I'm guessing that the same will be true of voltages in Japan; 100 volts will be the maximum but actual voltage will be less than 100 volts.

Besides this theoretical limit on power delivery, lower voltages also cause problems for induction motors (like those used in power tools). Low voltages increase current draws and therefore cause more heating, and the motor is easier to lock up (i.e. stop turning) under load. You can also run into these same problems when using long and/or small extension cords.

I don't know what part of Japan you are living in, but you should also double check the 60 Hz. The (southern) western parts of Japan are 60 Hz, but the (northern) eastern parts of Japan are 50 Hz. A motor designed for 60 Hz will run at 5/6 speed on 50 Hz (and see a little more heating too).

https://en.wikipedia.org/wiki/Electricity_sector_in_Japan#/media/File:Power_Grid_of_Japan.svg

If I were you, I'd see if anyone else has tried using US market tools and what their experience has been.

Good luck!

 

[MrTeal]

What Dave has said is correct. The amount of real power that can be delivered to a load goes up/down as the square of the voltage. On that basis, a voltage drop from 120 volts to 100 volts lowers the delivered power by 30%.

Yes, it's true that the voltage you actually get at a socket can vary over a range from 100 - 120 volts; it's (mostly) affected by how much demand is being placed on the feeder that you and your neighbors are sharing. The higher the loads, the higher the currents, and the greater the voltage drop from what's at the substation. There are control schemes for tap changers and shunt capacitors that help keep voltages reasonably close to 115 volt target, but it's inexact. People nearer the substation will generally have higher voltages than those connected towards the ends of a feeder.

I'm guessing that the same will be true of voltages in Japan; 100 volts will be the maximum but actual voltage will be less than 100 volts.

Besides this theoretical limit on power delivery, lower voltages also cause problems for induction motors (like those used in power tools). Low voltages increase current draws and therefore cause more heating, and the motor is easier to lock up (i.e. stop turning) under load. You can also run into these same problems when using long and/or small extension cords.

I don't know what part of Japan you are living in, but you should also double check the 60 Hz. The (southern) western parts of Japan are 60 Hz, but the (northern) eastern parts of Japan are 50 Hz. A motor designed for 60 Hz will run at 5/6 speed on 50 Hz (and see a little more heating too).

https://en.wikipedia.org/wiki/Electricity_sector_in_Japan#/media/File:Power_Grid_of_Japan.svg

If I were you, I'd see if anyone else has tried using US market tools and what their experience has been.

Good luck!

Running at 100V/50Hz would probably be better than 100V/60Hz anyway, since you should be reducing the voltage to an induction motor as you decrease frequency to keep the flux density the same.

@OP, unless you're planning on moving to a 120V/60Hz country, it would probably be best to just purchase tools rated for your country. The plugs in Japan are also ungrounded, so you'd have to make an ungrounded cheater cable which isn't necessarily advisable especially on tools that aren't double insulated or could be used in wet conditions. It will be tool dependent, but some things like air compressors might even have a hard time starting when cold due to the much lower starting torque. They might still work, but you won't be getting the performance you paid for. If you do want to play around with it, keep in mind you don't need a full isolation transformer to power your tools. You can buy cheap 30A variacs on eBay that would do what you need. Still not sure it's worth hauling that all around, but you could give it a try.

If you can get away with it, cordless tools might actually be your friend here since most of the new Li-Ion chargers should be universal input and a battery doesn't care what voltage and frequency your grid is.

 

[TheNiceGuy]

Thanks. I actually just checked my wall outlet with my VC97 electrical checker. It's reading 103.5 - 103.7 volts off a few outlets.
What does the 110/120 volt rateing mean on US appliances?
I looked around the Internet quite a bit, and there was mixed anecdotal unconclusive reports on use. Some of it appears to have come down to the hertz ( I'm 60 Hz which is good]. A couple guys said they are using a variety of music studio equipment from the states and had absolutely no problems. Another guy in the 50 Hz zone was running an arc welder which was behaving poorly and went back to normal when he got a converter. 50hz Hair curler bad. Power saw reported ok. Razor ok. Etc.
I'm thinking I'll just bite the bullet and not risk it since I can't return any of the stuff.

 

[TheNiceGuy]

Mr teal, I just saw your post, I had forgotten about the grounding issue. So appliances made for Japan will have special stuff to make up for the lack of a ground plug?
The battery thing is a good idea. I've actually got a decent multipurpose battery charger I hot wired into a PSU.
It's funny, some appliances actually are sold here with a physical 50/60 Hz switch on the outside that you can select depending what Area of the Country you live in.

 

[MrTeal]

Mr teal, I just saw your post, I had forgotten about the grounding issue. So appliances made for Japan will have special stuff to make up for the lack of a ground plug?

Well, not just Japan. Grounded devices with the three prongs have the ground connected to the metal case. If a wire breaks free and touches the outside of the case, it shorts to ground and blows the breaker. The trend is that more and more devices are double insulated and don't require a ground prong on their plug. They have additional insulating material to ensure that even if an exposed wire breaks free, it can't touch the chassis and make it live.

The possible danger comes if something is designed to use the ground as a safety, and then you clip it off or use a cheater. If something does go wrong, you could end up with 100V on the case of your tool and not be aware of it until you touch it.