Would a US dishwasher work on 220v with a transformer?

September 21, 2009 1:03 AM

Bringing a US Dishwasher to a 220V-powered country, providing I have a well rated transformer will there be any issues? Bonus points for FUD-less answers :)

So assuming I have a sufficiently-well rated transformer, know about the 50/60hz difference and adaptor I need due to the plumbing using different sized pipes...

Will there be any issues? Do US dishwasher manufacturers make assumptions about how hard/soft water is? Does anyone know if modern dishwashers would be affected by the frequency difference?

Has anyone tried to use a US dishwasher with a transformer and ran into issues or lack thereof?

* Pointing at manufacturer's recommendations isn't too helpful - KitchenAid specifically state that their 110V mixers don't work with 220V transformers, yet I've used one with a transformer for years with no ill effect.
** I've checked prices and even with the cost of shipping it makes sound financial sense to import one from the US.

posted by shimon to home & garden (17 comments total)

People do it all the time but there is a huge issue of practicality here. What country and are you renting or buying? Because I suspect there may be a host of other issues besides "will it work" that you have not considered.
posted by DarlingBri at 1:13 AM on September 21

"Do US dishwasher manufacturers make assumptions about how hard/soft water is?"

Not usually, they just have a requirement for sufficiently soft water in the installation manual and are quite happy to recommend the installation of a water softener.

"Does anyone know if modern dishwashers would be affected by the frequency difference?"

The kind of A/C motor (IE: Cheap) used in dishwashers probably aren't going to be hurt by running at 50Hz instead of 60Hz. However they are going to be running ~10% slower and that will mean reduced jet pressure and spray arm velocity which will affect the wash action. Whether that will be a noticeable difference is going to vary wildly depending on the unit and the end user. Maximum drain lift will also be reduced. Also any timer devices taking a reference from the line frequency (like electric motor driven timers) will run slower and therefor whatever they control will run longer.
posted by Mitheral at 1:33 AM on September 21 [1 favorite]

A mixer is an intermittently loaded device... the usual interval of use is such that any adverse consequences have less time to impact the motor. Also, the motors themselves are not AC motors, but are DC motors with circuitry in between the mains and the motor to regulate speed. This could be as simple as a phase angle triac driver with a bridge rectifier on the output, and the speed control is the phase angle adjustment. With this scenario, the frequency is much less of an issue. Drawing a conclusion about dishwasher operation based on mixer success is technically unsound.

The motors in a dishwasher are almost certainly different... AC induction motors. They run constant speed and are likely connected directly to the mains and they run for much longer periods of time in normal operation. They will also run at at different speed at a different frequency. As frequency decreases, the voltage should decrease, too. If you decide to run the unit on lower frequency, decrease the target voltage of the motor to 5/6 (i.e. 50/60ths) of the name plate voltage (i.e., 120v becomes 100V). If the machine cycle is determined by a motor driven timer, the unit will run longer, too. (A 1 hour cycle would be 1.2 hours long.) If the unit is driven by a microcontroller-based circuit, this may not be the case, depending on how the unit keeps track of time. In the old days, 60 Hz from the power lines might have been used to run a clock routine. (I've done that in software before). These days, it's less common, so the run time might be unaffected.

For the headaches, I'd personally buy one there and resell it when done. If it's that expensive to buy one over there, then the resale value should be pretty good, too.

Any design is an exercise in trade-offs. Baseline assumptions about the operating environment inform a multitude of decisions. You are second guessing some really smart folks who have evaluated many scores of components in a product, and it is unlikely that an off-the-cuff, layman's field mods would yield the anticipated performance, reliability, and safety of the designer's decisions.

Here is some motor info for you to chew on while you ponder the wisdom of doing this.
posted by FauxScot at 1:45 AM on September 21

If you are going to do this, don't forget to mount the transformer such that a worst-case kitchen flood poses no danger.
posted by fatllama at 2:13 AM on September 21 [1 favorite]

Nthing the 50/60 hz issue. Ever taken a hairdrier to a country work on a different voltage system? They either run noticably slower and cooler or sound like a bee trapped in a biscuit tin. Cheap dishwashers are a few hundred dollars or equivalent - spend the money to avoid this headache.
posted by SueDenim at 2:45 AM on September 21

Most dishwashers include a heating element. Heating elements chew up lots and lots of electricity. That transformer is going to have to be pretty grunty; might weigh damn near as much as the dishwasher.
posted by flabdablet at 2:48 AM on September 21

Is there a particular reason you want to do this? are you rather fond of your dishwasher?
posted by mary8nne at 2:56 AM on September 21

If you are moving to the UK keep in mind that the people you can hire to install it will be completely unfamiliar with it. Given that they often suck at installing dishwashers with familiar features I'd be very concerned.

Also you could invalidate your home insurance.

Our rental lease here actually contains a clause prohibiting us from starting the dishwasher or laundry washer and going out.
posted by srboisvert at 3:01 AM on September 21

What about space considerations? I live in Paris and have never seen a kitchen with enough depth under the countertops to support an American dishwasher, but I suppose this problem is specific to large cities in certain European countries.

Also, you didn't mention which country you're in.. but European dishwashers (and toilets, and showers, and all other water-consuming items) tend to be super-efficient. Therefore, I would be concerned about excess water consumption, as well as making sure the drainage pipe can support it (although admittedly I'm not a plumber).

As for hard/soft water: As long as you can buy water-softening tablets where you live, this shouldn't be an issue.
posted by helios at 4:36 AM on September 21

I can't find a straight answer as to whether or not the UK is one phase/neutral or two phase 240 and would suggest finding something from the UK that's dead (but with an OK motor) and putting that in the thing, but there is also that heating element to contend with. The heating element will draw the lion's share of the power, btw.

Not sure what country you're looking at, but we have pretty much the same range of water hardnesses within the US as the rest of the world. Burton on Trent's water is about twice as hard as St. Louis'. Plzen in the Czech Republic is about a zillion times softer. (Guess whose beer style we're copying?)
posted by Kid Charlemagne at 5:13 AM on September 21

helios is right - you might have size issues. For example, USA appliances are different sizes to standard EU kitchen units: http://en.wikipedia.org/wiki/Dishwasher#Size

Not to mention shipping costs. Those things are heavy.
posted by DangerIsMyMiddleName at 6:31 AM on September 21

Wouldn't the cost of an appropriate transformer be more than a whole new dishwasher?
posted by gjc at 6:40 AM on September 21

On the transformer side -

I futzed around with all sorts of dinky transformers in the uk.

Most of them were too small to run anything beefy.. Until I went to a builder supply store. They sold a worksite transformer. 3200watts, designed to run 110v power tools. It was a BEAST and only cost 50gbp (it was slightly used). I had to wire in a custom plug since it was a 16A worksite plug to power stuff, but it worked like a champ.

The problem with pairing it with a standard transform is that anything that moves or heats spikes voltage. And most of the normal boring transforms can't deal with it and the fuse goes.

The worksite ones are made for bigger stuff.
posted by Lord_Pall at 8:24 AM on September 21

I did almost the opposite about 5 years ago, throwing a 220v clothes washer onto a 120v US circuit. No US manufacturer makes a good washer/dryer and the euro brands are $$$$ in the US, so I imported.

1) Don't. Honestly, don't. Take a good look at what's available in the country you're moving to. Most American appliances are rubbish and are priced appropriately. The only reason I imported my washer & dryer was that I couldn't find what I wanted in the US.

2) OVERsize the transformer. Not quite as critical with a dishwasher as a clothes washer due to the constant duty cycle of a dishwasher vs. intermittent of a front-load washer, but well worth it. Let's be honest, we're already pushing things hard as it is.

3) Frequency doesn't seem to matter all that much. Yes, motors will run slower if they're AC motors. Fortunately my washer was all DC motors so no speed difference that I've noticed. In your case you'd be going to a slower speed so in theory the motor would run somewhat cooler. DC motor probably would be a good idea, but I don't know of any US manufacturers who use them. A few of the Euros do.

4) Pick a simple machine, but not a cheap machine. You want something you can work on if need be, but also something that won't need repair (few bells & whistles). Let's face it, you're going to be on your own when it comes to repairs and parts. OR try to find a machine that uses similar/same parts as what you have available in your new country. My Gorenje washer and dryer have many parts in common with the domestic Bosch Axxis units. Not 100% parts match, but close enough that I could make it work in an emergency. Pick up spare parts of anything you think you might need.

5) Plumbing connections WILL be different. The civilised world uses metric, the US is stuck in ancient imperial units. Make sure you can get ahold of the appropriate adapters or make the hoses yourself before undertaking this endeavour.

6) Helios brings up an excellent point -- water consumption & disposal issues. American appliances use gobs of water and electricity compared to their euro counterparts. My washer uses ~14 gallons of water at its maximum settings. The American washer I ripped out used 62 gallons. I'm not sure the plumbing in my old London flat would have been capable of handling such a volume of water being dumped into it.

7) Never trust this arrangement. Realise that you've created a bastard child and treat it as such. This equipment wasn't meant for this. After 5 years with my washer, I still won't run it if I'm not planning on being around it.
posted by OTA at 9:00 AM on September 21

(ota... motors will run hotter unless the voltage is scaled down for the reduced frequency. )

I'm totally with you on the 'buy local' advice, though.
posted by FauxScot at 9:19 AM on September 21

One point to consider should you choose to do something like this, is that you will need a 50Hz transformer.

A transformer rated for 60Hz and run at 50Hz will get hot.
posted by HiroProtagonist at 10:03 PM on September 21

More good advice here.
posted by flabdablet at 4:41 AM on September 22