Advice needed on inverter transformer selection - Page 1
Forum section: electronics / beginners

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:25:24 pm
content: My wife and I are moving to Europe and I'm coming across some challenges.Originally, we were planning on 'getting rid' of most of our electric devices and repurchasing once we were there. This is proving very difficult as our budget is stretched very tight already.There are some items that I'd (my wife) would like to keep since we won't be in a financial position to repurchase. These include: Electrolux vacuum, food processor, stand mixer and a few other high wattage devices.I was hoping it would be feasible to connect these items to an inverter whenever they were needed but I am completely clueless when it comes to these things.I would really appreciate some guidance here on selecting and setting up such a configuration (if I haven't provided enough information, kindly let me know the details you require).Thank you in advance for any help.Best...

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:28:58 pm
content: What about just getting a transformer?

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:32:22 pm
content: Quote from: Dajgoro on August 10, 2013, 05:28:58 pmI'm already doing this for devices rated at 50/60 Hz but I can't run 60Hz devices on only a step-down transformer without damaging the original circuit, motor, etc.

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:35:54 pm
content: What about selling such 60Hz devices on classifieds and buying new ones when you come to Europe?

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:39:04 pm
content: Quote from: Dajgoro on August 10, 2013, 05:35:54 pmToo costly. Resale value compared to new purchase price makes this unrealistic...

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:42:40 pm
content: How much power do you need anyway? Edit:3000W?

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:44:48 pm
content: Quote from: Dajgoro on August 10, 2013, 05:42:40 pmMuch, much more than that. Again, devices such as vacuum, mixer, etc.

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:54:25 pm
content: *I missed the vacuum part, so I edited the post and caused a bit of a mess.Ouch, that is a lot of power.I am not sure that there is a cheap enough solution for that.That is why I suggested reselling the items.Are you absolutely sure that those devices would be damaged when running at 50Hz?If not, maybe you could get a 12V to 110V/60Hz inverter for solar panels, and then just use a regular 230/12V switching circuit.

author: Zero999
author_rank: Super Contributor
timestamp: August 10, 2013, 08:58:16 pm
content: Just use a transformer.A vacuum cleaner will certainly be fine on 50Hz as it'll have a universal motor so would even work on DC if you wanted.The other devices should be fine too as they most likely have brushed motors too but they'll be parallel wound which means they'll run a little slower but have a little more torque because the field current will be marginally higher. I doubt they use induction motors which are uncommon in household appliances because they're so bulky.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 11, 2013, 06:42:58 am
content: Quote from: Hero999 on August 10, 2013, 08:58:16 pmOK, makes sense on paper and forgive me for the tenacity but this could be costly if 'things don't work out' - how confident are you of the longevity of the down-converted devices?Thanks for your input.

author: SeanB
author_rank: Super Contributor
timestamp: August 11, 2013, 07:32:45 am
content: Only items you will have trouble with are washing machines and tumble driers. Washing machines because they will run a little slower and will not spin as fast if they use induction motors ( most non electronic ones, if it whines then it has a universal motor or a BLDC motor) and driers will not turn as fast. Dishwashers will probably work, but will take longer to clean dishes. Simple solution is to not take it and learn how to wash dishes.As to how long they will last how long is a piece of string. Life of appliances is hard to tell except statistically, and often they are designed for a certain lifetime irrespective. You might run into problems with spares and wear items, and they might not work because of vibration during shipping damaging them.

author: G7PSK
author_rank: Super Contributor
timestamp: August 11, 2013, 08:48:34 am
content: I don't know which part of europe you are moving to, but for a vacuum cleaner and a food mixer it is hardly worth bringing it across the pond. An Electrolux vacuum cleaner can be had on Amazon for £40.00http://www.amazon.co.uk/Electrolux-Carvac-Cylinder-Vacuum-Cleaner/dp/B000ND6ZM6/ref=sr_1_11?ie=UTF8&qid=1376210182&sr=8-11&keywords=vacuum+cleanersAnd a food processor for similar price,ww.amazon.co.uk/Kenwood-Compact-FP120-Litre-Processor/dp/B001C3DRDG/ref=sr_1_1?s=kitchen&ie=UTF8&qid=1376210531&sr=1-1&keywords=food+processorsIt will cost £50.00 plus for a transformer which will have to be lugged around the house and you may even end up wanting two or more.Personally I cannot see that it makes any sense to ship your stuff from the US as it will just add weight and bulk to the other things that you really don't want to leave at home.

author: amyk
author_rank: Super Contributor
timestamp: August 11, 2013, 12:13:24 pm
content: Quote from: Hero999 on August 10, 2013, 08:58:16 pmSome newer/higher power ones use BLDC, which is also OK as they have an SMPS input stage.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 11, 2013, 05:38:37 pm
content: Thank you all very much for the assistance!Quote from: SeanB on August 11, 2013, 07:32:45 amI meant life expectancy running outside of recommended specification (ie 50Hz instead of 60Hz). I'm not planning on bringing a dishwasher, lol but fair enough - also, a sincere thank you for jumping into the thread.Quote from: G7PSK on August 11, 2013, 08:48:34 amI wish it was that easy. The vacuum in question is an older model (made before Electrolux took the downward spiral and original cost was $3000); the mixer is one of the larger model made by kitchen aid ($600), food processor, etc. Cost of shipping is almost negligible as we're using a container service for our entire household (it'll cost pennies to add these items). Again, thank you very much for your help.Quote from: amyk on August 11, 2013, 12:13:24 pmGood info, thank you!I was considering using this model:http://www.amazon.com/buyVoltageConverters-Voltage-Converter-Regulator-Heavy/dp/B003UQMDWY/ref=sr_1_9?s=electronics&ie=UTF8&qid=1376242301&sr=1-9&keywords=step+down+transformerand only running one item at a time.BTW, it looks like the highest wattage item I have is 2000 watts.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: August 11, 2013, 06:17:01 pm
content: Hey OPussually . you should run 50Hz devices on 60Hz ( I personally ren at 400Hz ! and the power factor was increased by few digits ! ) , the problem is that you got 60Hz stuff , in that case you only gonna lower the efficiency of the device ..playing with mains is not A game hence I won't tell you what just went into my mindthat "5000" device firstly pop the " chinese " and then ... well I don't gonna trust these figures due to my bad experience with them , they simply are piss of junk witch should be thrown to the occian ...this 5000 figure may be reveal as 1 third of that ... in that case .. you where screwed ...please read the comments below , as you may find out , at 140$ ... my brain has some great difficulties figure out how *true* 5KW device can be sold ..Plus , I didn't saw any frequency conversion spec in that listing . If you did . please forgive me . if you didn't ... watch out for these things ...My 2 Cent ..

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 11, 2013, 08:02:11 pm
content: Quote from: eevblogfan on August 11, 2013, 06:17:01 pmNo, I don't really expect 5KW out of these things (I assume that's max surge value); I'll be running a max of 2KW at a time out of the transformer. Also, you are correct, there is no frequency conversion happening there (I would imagine that there's no way on the planet to get a 5KW inverter for ~$150, lol.I agree about the Chinese devices - do you have a better suggestion for the step-down?

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 11, 2013, 08:08:53 pm
content: Or maybe this one:http://www.bhphotovideo.com/c/product/889533-REG/TOPOW_TOPOW_AVR5000_Step_Down_Transformer.htmlEDIT: Actually, I'm really liking this one (simply due to the weight):http://www.samstores.com/productdetails.php?pid=1011&gclid=CL6JnYWa9rgCFcqf4AodhxgA5g

author: bookaboo
author_rank: Frequent Contributor
timestamp: August 11, 2013, 11:05:49 pm
content: There's no way on earth that the amazon unit is a 5000w inverter at $144.00, not even the cheapest chinese "modified sine" inverter is that price... it looks like thats just a transformer so you are still stuck with the frequency.For a low end 5000w inverter you are looking at £500 and I wouldn't recommend most of those for constant use, I haven't actually seen any "good low end" units in that wattage.You could go for a PSW7 type which are decent quality but horribly inefficientThe right inverter would be something like a Victron, but that's going to be £2000-£2500 and even the best inverter can go bang.Plus you have to consider battery packs etc.The only thing that *might* work is if you picked up a second hand industrial UPS type unit.But as others have said I'd really look at a simple transformer, if you can research the specs of your units or contact the manufacturer and ask them straight if the frequency is important. If its not you might even be able to have someone modify the units (i.e new internal transformer or if you are really luck just rewire the taps).I'll also say that I'd sell and buy new.1) by adding layers of technology (even transformers) you make it more unreliable2) You might have difficulty finding spares in EU for old USA items when they units need service3) Your original units were expensive, but Id just buy lower spec over here... unless your doing something commercially you probably dont need super spec appliances. You might even turn a profit on this.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 11, 2013, 11:35:34 pm
content: @bookaboo:No, that is not an inverter - just a step-down transformer. My question (has trancended to) which transformer (rather than which inverter). Thanks for your input.

author: bookaboo
author_rank: Frequent Contributor
timestamp: August 12, 2013, 09:03:58 am
content: I guess something like this appropriately sized may do.http://www.amazon.co.uk/3-3KVA-Transformer-Power-Tools-Heavy/dp/B007WRTKLY/ref=sr_1_3?ie=UTF8&qid=1376298000&sr=8-3&keywords=110v+transformerVery popular over here for construction work.I remember my uncle bringing all sorts of 110v stuff home from USA and we ran it on these (mostly horrible Christmas decorations which was his big thing!)Maybe someone better versed in transformers can confirm if there's a big variation in efficiency between different types.

author: G7PSK
author_rank: Super Contributor
timestamp: August 12, 2013, 09:14:06 am
content: Any equipment with a plain induction motor that is designed for 60Hz will quickly overheat and burn out at 50Hz, I know this from personal experience universal motors will be OK.

author: richard.cs
author_rank: Super Contributor
timestamp: August 12, 2013, 12:05:56 pm
content: 60 Hz induction motors (and transformers, etc) can be run on 50 Hz safely provided the voltage is also lowered in proportion. A 120V 60Hz motor run on 100V 50Hz will see the same peak current flow and flux density as in its origonal aplication and will not overheat. Power output will be reduced but whether this matters really depends on the aplication and how marginal the design was to start with.US washing machines tend to be induction motors with many different windings for different speeds. European ones tend to be universal motors. So far as I'm aware vacuum cleaners (made after about 1950) are all universal motors.

author: Zero999
author_rank: Super Contributor
timestamp: August 12, 2013, 03:54:08 pm
content: Buy a 110V transformer which should be enough of a voltage drop, if you're worried.That cheap Chinese converter is a greater liability than a frequency reduction.Most inverters you get are modified sinewave, unless you pay more, which will shorten the life of any frequency sensitive equipment more than the change from 60Hz to 50Hz will.An auto-transformer could be used because it will be half of the size of an isolation transformer.Non of the appliances you've listed are likely to use induction motors which tend to be the most fussy. The vacuum will even run of 120VDC so isn't a problem. The food processor will have parallel field brushed motor so just run a little slower, due to a slightly higher field current.

author: M. András
author_rank: Super Contributor
timestamp: August 12, 2013, 04:11:50 pm
content: Quote from: eevblogfan on August 11, 2013, 06:17:01 pmi bet its an overrated transformer nothing else even for that its too cheap

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 12, 2013, 05:12:38 pm
content: Hey guys, thank you for all the help. I don't think anyone noticed but after the initial advice on not using the inverter, I turned the discussion into which step-down transformer would work well. Once again, the items I linked were for transformers, not inverters.Sincere thanks to all that responded; if anyone has any more transformer recommendations I'd be happy to hear them.Best.

author: richard.cs
author_rank: Super Contributor
timestamp: August 12, 2013, 05:26:48 pm
content: Quote from: StubbornGreek on August 12, 2013, 05:12:38 pmI would second what bookaboo said about the 110V building site transformers. They're not that expensive new or used, available in a selection of sizes, and are likely to last forever. I suspect all but the most cheaply built 120V 60 Hz stuff will be OK on 110V 50 Hz, and certainly wouldn't die instantly. You could just power stuff up and see if it gets unusually warm, if it does then use a very small bucking transformer (say a 240V to 10V with a secondary of a couple of amps wired in antiseries with the 110V output) to loose another 10 Volts or so.Could you perhaps post a full list of appliances you want to use with any information you know about them and we'll do our best to say fine/maybe/no and maybe give you a few things you could check/test to confirm.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 13, 2013, 06:40:08 am
content: Quote from: richard.cs on August 12, 2013, 05:26:48 pmNo worries, richard.cs. I feel that I have a better handle on my needs now. Thank you for jumping into the thread.