Will This Transformer Do For Tool Purchased In USA? - Page 1
Forum section: electronics / general

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 06, 2012, 07:46:09 am
content: Hello, i have this cordless screwdriver/drill that i bought from USA and want to use it with 220V-50Hz electricity in Israel withthis kind of wall socket(adapter from US plug to Israeli plug i already have). This is what i see on sticker under the bottom of its charger:There is no mention of wattage on sticker, but is there a way tofind out/calculate? Will the following charger be a good fit for tool? I heard that it is better to get transformer with 20% more wattage than tool requires just in case.Thank you.

author: Pentium100
author_rank: Frequent Contributor
timestamp: March 06, 2012, 07:53:52 am
content: Also find out how much an autotransfomer costs. Maybe it is cheaper than a new charger.It seems to me that this charger has some intelligence built in, not just a DC power supply, so it may be expensive.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 06, 2012, 08:11:50 am
content: Quote from: Pentium100 on March 06, 2012, 07:53:52 amIt's not, only over $10.However this one is over $88:

author: sonicj
author_rank: Frequent Contributor
timestamp: March 06, 2012, 08:50:58 am
content: Quote from: Boris_yo on March 06, 2012, 07:46:09 amamps x volts = watts2A x 120V = 240W20% of 240W is 48W so... around 300 Watts would be appropriate.

author: Pentium100
author_rank: Frequent Contributor
timestamp: March 06, 2012, 08:51:43 am
content: Wow, a 300W autotransformer in my local electronics store only costs ~30EUR.Now that I read your post one more time, it turns out that you are asking about an autotransfomer too (for whatever reason at first I believed it was an AC/DC adapter).No, you need the autotransformer to be at least 240VA, because the charger needs 120V and 2A (it probably uses a series capacitor to reduce the voltage resulting in a very low power factor).

author: IanB
author_rank: Super Contributor
timestamp: March 06, 2012, 08:56:08 am
content: Unless it is very inefficient I can't believe that battery charger draws more than about 100 W from the mains, in spite of the 2.0 A written on the label. Perhaps the 2.0 A is the peak surge current for breaker/fuse rating purposes?I would try a 100 W transformer and see what happens. Also make sure it is a proper transformer and not an electronic one. The electronic ones are only for resistive loads like hair dryers and are only rated for short periods of operation.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 06, 2012, 09:44:07 am
content: People tell me they to buy adapter for around $10 for tool from US to work. They say i don't need converter and only adapter. One told me he bought such adapter with input 230v 26VA fore his 20v tool and all works well for him.I need to know what electrician experts on this forum think about this. Thanks.

author: Pentium100
author_rank: Frequent Contributor
timestamp: March 06, 2012, 10:10:07 am
content: Quote from: IanB on March 06, 2012, 08:56:08 amJudging from the warning that the terminals are live and the 2A current rating I think the charger uses a series capacitor to reduce the voltage instead of a transformer. A series capacitor does not dissipate power, but the power factor becomes really low. I attached an example circuit diagram.Because transformers are actually rated in VA (apparent power), you need a transformer that can supply the current even though it does not do any useful work.

author: IanB
author_rank: Super Contributor
timestamp: March 06, 2012, 10:16:48 am
content: Quote from: Boris_yo on March 06, 2012, 09:44:07 amYour DeWalt battery charger has 120 V AC 60 Hz 2.0 A written on it.If you take that at face value you need a voltage converter that can output 120 V at 2.0 A at least, which would be a 300 W voltage converter transformer allowing for a safety margin. You won't buy one of those for $10.You can't simply use a plug adapter with that battery charger as it requires 120 V.The moral of the story is to buy things in Israel designed for use in Israel. Don't buy things from America and try to use them where they were not designed to be used.

author: IanB
author_rank: Super Contributor
timestamp: March 06, 2012, 10:21:47 am
content: Quote from: Pentium100 on March 06, 2012, 10:10:07 amI see that. But it seems like incredibly poor design for something that needs 2-3 A, which is why I had my doubts. But since I don't have it in my hands to take apart, who knows? With the information printed on the label we have to take it at face value.

author: Unknown
author_rank: Unknown
timestamp: March 06, 2012, 10:25:48 am
content: If you take the printed information at face value, you would also have to convert the 50 Hz power to 60 Hz, which is going to be much more complex than a simple transformer. Most devices rectify it anyway and don't care, but it would result in a decrease in charging current of 15% in Pentium100's proposed circuit, and an increase in ripple. I wouldn't expect such a big cap to be cheaper than a transformer either, but who knows.

author: Pentium100
author_rank: Frequent Contributor
timestamp: March 06, 2012, 10:39:57 am
content: Quote from: IanB on March 06, 2012, 10:16:48 amOr figure out a way how to make them work where you live.Quote from: alm on March 06, 2012, 10:25:48 amMotor run capacitors are not very expensive.On the other hand, it could be just a switching power supply (without a transformer). That also can have a low power factor, but probably not THAT low (~0.2).I would take it apart (if possible) and figure out how to modify it to work with 240V. If it really has a CR dropper, then reducing the capacitance could work.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 06, 2012, 10:40:59 am
content: Quote from: IanBWhat i meant adapter which is 230V - 110V, but not converter. At least that is what i was told in local forum. People said i don't need converter, but i need 230V - 110V adapter. I always assumed that adapter is unit that simply adapts abroad power plugs tpo local power plugs and vise versa, but they say it is 230V - 110V which i can only assume it is converter, but it is not, according to their statement.Just want to remind that tool is cordless and works only on Ni-CAD battery so it is battery that needs to be charged through charger.

author: Pentium100
author_rank: Frequent Contributor
timestamp: March 06, 2012, 10:45:01 am
content: Quote from: Boris_yo on March 06, 2012, 10:40:59 amIt is an autotransformer, which is like a regular transformer but it only has one winding with taps. It can step up/down the voltage just like a regular transformer and is cheaper, but does not provide isolation, so the "secondary" is live.

author: G7PSK
author_rank: Super Contributor
timestamp: March 06, 2012, 10:54:11 am
content: If the charger contains a transformer it may burn out on 50HZ as it is rated for 60HZ and at 50 it will draw more current if its a switch mode unit it may be quite happy at 240 volts as these things tend to be made for use anywhere and the only make the pins for the socket different for the various markets.

author: Pentium100
author_rank: Frequent Contributor
timestamp: March 06, 2012, 11:05:44 am
content: Quote from: G7PSK on March 06, 2012, 10:54:11 amIf it were OK at 240V that would be written on the sticker. It can use input capacitors rated for 200V for example and they wuld blow up if connected to 240V.I have two low power devices that are 120V/60Hz and they both work OK on 50Hz. Though you should find out if the device gets too hot when connected to 50Hz.

author: T4P
author_rank: Super Contributor
timestamp: March 06, 2012, 05:36:52 pm
content: Hmm , i wonder what's inside the charger , how does a charger draw more then 240W is beyond me .

author: Pentium100
author_rank: Frequent Contributor
timestamp: March 06, 2012, 11:43:49 pm
content: Quote from: Dave.S on March 06, 2012, 05:36:52 pmI don;t think it draws 240W. It can draw a lot of current if it has a really low power factor. After all, if I plug a 20uF capacitor to 240V it will draw a lot of current, but use almost no power.

author: T4P
author_rank: Super Contributor
timestamp: March 07, 2012, 12:29:07 pm
content: Quote from: Pentium100 on March 06, 2012, 11:43:49 pmMaybe on startup . SMPS can do such shit to energize the caps , it draws a massive amount to energize those low ESR caps.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 20, 2012, 10:06:06 pm
content: Here is what DeWalt support told me:QuoteAre these step down transformer and inverters the ones that cost a lot?

author: T4P
author_rank: Super Contributor
timestamp: March 21, 2012, 01:46:52 am
content: Quote from: Boris_yo on March 20, 2012, 10:06:06 pmNo .

author: Monkeh
author_rank: Super Contributor
timestamp: March 21, 2012, 01:52:27 am
content: A transformer for that is liable to cost more than a suitable replacement charger. I highly doubt the batteries are any different (except their hilarious '20V' ones) to ones from Europe.

author: sonicj
author_rank: Frequent Contributor
timestamp: March 21, 2012, 06:24:00 am
content: Quote from: Monkeh on March 21, 2012, 01:52:27 amthe management dickheads who came up with the 20V Max lineup need to be punched in the face and fired!the success and longevity of the 18V XRP line is their clear competitive advantage over the competition."hey, lets jump on the flatpack bandwagon and f*** over all of long time customers by investing all of our battery advancements in this new incompatible "20V' format and raise the price on all of the old s**t so maintaining old tools no longer looks cost effective." ******bags!-sj

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 21, 2012, 08:55:01 am
content: Quote from: sonicj on March 06, 2012, 08:50:58 amisn't there a power factor in ohm's law for ac or something ?

author: PetrosA
author_rank: Frequent Contributor
timestamp: March 21, 2012, 11:32:08 am
content: Your cheapest option may be to buy just the charger in Israel. You will need at least a 300W transformer for the charger to work. I have a 375W inverter in my truck and you can hear it bog down when a charger goes into charge mode (I have chargers from Hilti, Metabo, Fein and Milwaukee and they all draw a lot of current when charging). Some cycle on and off, putting a heavy draw on the inverter each time. Another option may be to replace the transformer inside the charger.

author: SeanB
author_rank: Super Contributor
timestamp: March 21, 2012, 11:47:13 am
content: There is a big difference between a 220-115 adaptor and an autotransformer. The adaptor is basically a glorified light dimmer, designed to drive 115V resistive loads ( like heaters and clothes irons) with enough power to heat to the same level as if they are plugged into a US socket. They do this by horribly mangling the input voltage, and anything with a 115V transformer on the input will be fried very fast by it. Electronics also will blow up either instantly or in a few minutes.The autotransformer takes 220VAC input, and supplies 115VAC output, giving a good sine wave at 50 Hz ( like the input) that will operate all electronics properly.Using a converter with the charger you have will likely blow up the battery rather quickly, as the fast current spikes will overload both the charger and the battery. It will do a spectacular imitation of a flash bang, complete with the corrosive smoke and flying shrapnel. Not exactly what you want on your workbench, and not good for your underwear either. these chargers run hot as it is.

author: Pentium100
author_rank: Frequent Contributor
timestamp: March 22, 2012, 12:26:12 am
content: Quote from: SeanB on March 21, 2012, 11:47:13 amWow, I'm glad I didn't get one of those when I bought a cheap 220-110 adapter. The one I have is an autotransformer, I don't think my local electronics store even has the electronic ones.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 22, 2012, 02:24:57 am
content: Take it apart. If it is indeed a capacitive charger, you can just replace the cap with one of double the voltage and half the capacitance.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 24, 2012, 10:39:03 am
content: Found this one guys:Is it really up to 450W? Says not to use 30VA on hair dryer (on the picture) and also on the website says not to use hearing devices, electronical devices, home appliances and devices with big motors.Quote from: PetrosA on March 21, 2012, 11:32:08 amIts cost is close to 300W transformer. I think it is better to get transformer since i can use it with something else in the future just in case.Quote from: NiHaoMikeI am not qualified to do such a task.

author: SeanB
author_rank: Super Contributor
timestamp: March 24, 2012, 10:48:44 am
content: Light dimmer with 2 settings - high crisp or low crisp.I found ou the difference with the original Mac where they were originally 115V units, and the supplier gave a small converter with the first units ( and a replacement power supply board 2 months later) instead of a proper transformer. Later they got 230V boards and replaced these all.

author: jamesp15
author_rank: Regular Contributor
timestamp: March 24, 2012, 05:00:54 pm
content: This is NOT my post/pictures, but I found pictures of the inside of the charger if it may help anyone.http://dewaltownersgroup.com/index.php?topic=869.0If anyone needs more detailed pictures, I can take one of my own apart and take some.

author: T4P
author_rank: Super Contributor
timestamp: March 24, 2012, 05:39:17 pm
content: Looks like it's a switchmode PSU ( Why do some people think it's not isolated ? )And the 350W rating only lasts for a few microseconds while charging the input caps .

author: IanB
author_rank: Super Contributor
timestamp: March 24, 2012, 06:09:10 pm
content: Quote from: Boris_yo on March 24, 2012, 10:39:03 amThat is an electronic travel adapter. It can only be used for short periods to run hair dryers or travel irons or electric cup heaters, things like that. It cannot be used for any electronic device, nor can it be used for long periods. It can't be used for your battery charger.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 31, 2012, 06:22:36 am
content: Quote from: IanB on March 24, 2012, 06:09:10 pmThanks IanB for information. Can you advice on this one?http://www.dealextreme.com/p/600w-aquarium-intermittent-timer-switch-adapter-blue-ac-220v-2-flat-pin-plug-122564

author: Unknown
author_rank: Unknown
timestamp: March 31, 2012, 06:53:02 am
content: Quote from: Boris_yo on March 31, 2012, 06:22:36 amI can! Try reading the item title. Only transforming that will do will be transforming connected 110V gear into smoke!

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 31, 2012, 08:33:05 am
content: Here is what i found today about DeWalt charger:http://dewalt-uk.custhelp.com/app/answers/detail/a_id/753Is it that bad to use transformer? Does that mean the only way out is to buy original appropriate charger for my country?

author: Unknown
author_rank: Unknown
timestamp: March 31, 2012, 08:45:27 am
content: Quote from: Boris_yo on March 31, 2012, 08:33:05 amNo! Nothing wrong with using a CORRECTLY RATED stepdown transformer apart from it being more cumbersome. The device you posted last WAS NOT a transformer!QuoteNo!

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 31, 2012, 11:29:23 am
content: Quote from: Uncle Vernon on March 31, 2012, 08:45:27 amNo need to shout Vernon. Patience is a virtue.I did not assume the last device to be a stepdown transformer. I was referring to DeWalt's explanation about chargers. Additionally, do you think purchasing stepdown transformer instead of original charger will make more sense because transformer can be used for other purposes as well?

author: Unknown
author_rank: Unknown
timestamp: March 31, 2012, 01:05:34 pm
content: Quote from: Boris_yo on March 31, 2012, 11:29:23 amYes there is! I have enough years up to be entitled to be short. Equally I could reply no need to ask the bleeding obvious!QuoteA virtue indeed, but a virtue tested by repetition.QuoteThen why the hell was it included in the discussion?QuoteWhere the hell did DeWalt make reference to dubious Asian timer switches?QuoteThat depends entirely upon your intended use. If the tool is carted about like most are with the charger in a heavy duty case then having to carry/remember an additional heave stepdown TX will soon become a right pain. If the charger livesin the shed/garage then it won't be much of a problem. Your step down needs to be sufficient for the start-up and running current demands of your charger.No one can tell you what set of compromises will workbest for you, that's a choice you have to make for yourself. What works for someone else may not be your best option.If you want my opinion I'd by the local charger to be sure not to add yet another annoyance to my day, for someone else one a tight budget a TX and USA charger may be the answer to their prayers. Ask for support by all means but remember when you are asking for opinions everyone has one, some people have more. Only opinion that will matter to you in the end is your own.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 31, 2012, 01:57:49 pm
content: Quote from: Uncle Vernon on March 31, 2012, 01:05:34 pmBecause i thought this one would work for me.Quote from: Uncle VernonQuote from: Boris_yoI have posted link to DeWalt's information webpage about using US chargers in UK.

author: G7PSK
author_rank: Super Contributor
timestamp: March 31, 2012, 03:16:02 pm
content: If you want to use the US charger and are thinking of buying other US tools why not not get a suitable US inverter and run the unit of that. You will then be able to run the charger mobile and getting a suitable 12 Volt source is a lot easier for charging the unit at home.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: March 31, 2012, 03:22:34 pm
content: Quote from: G7PSK on March 31, 2012, 03:16:02 pmYou mean i could use US tools around the world with inverter and appropriate wall socket adapters? What is the difference between transformer and inverter by the way?

author: Monkeh
author_rank: Super Contributor
timestamp: March 31, 2012, 03:24:51 pm
content: Oh, jeez...Just go buy the proper charger already.

author: G7PSK
author_rank: Super Contributor
timestamp: March 31, 2012, 09:31:08 pm
content: I meant the type of inverter that is used in Vehicles or campers etc input 12 volts output 120 volt 60HZ

author: Unknown
author_rank: Unknown
timestamp: April 01, 2012, 01:03:00 am
content: Quote from: Boris_yo on March 31, 2012, 03:22:34 pmGoogle is your friend!http://www.google.com.au/search?q=What+is+the+difference+between+transformer+and+inverter&ie=utf-8&oe=utf-8&aq=t

author: Unknown
author_rank: Unknown
timestamp: April 01, 2012, 01:24:39 am
content: Quote from: G7PSK on March 31, 2012, 03:16:02 pmEr Price? That and you now have two extra pieces of crap to cart about. A hefty mains powered supply? and a 300W plus inverter.QuoteThis assumes the OP is a driver or owner of a motor car and travels sufficient distance to sufficiently charge the tool batteries. If not you again back into a mess of trouble with run down vehicle batteries etc. Running a vehicle just to charge batteries is not exactly efficient. And yes I know a vehicle isn't the only source of suitable 12VDC. You could also carry a compass, a solar panel, a charger regulator, and an inverter, to charge the tool batteries. (don't count on doing too much work with it at night or on cloudy days) Hey you could even carry a suitable windmill.All of which leads back to suggestions such asQuote from: Monkeh on March 31, 2012, 03:24:51 pmIf you want to use the US charger you need at least a 350VA rated transformer, no amount of wishing or magic is going to change that. The DeWalt advice refers mostly to complying with nanny state workplace legislation than with a transformer being able to operate correctly.eBay will have hundreds of enclosed 350W+ rated 240 to 110V stepdown transformers listed at any possible moment. Just have a safety check done on anything of dubious origin done before plugging it in.On evaluation of all factors the advice offered above by Monkeh is probably the best you can get.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: April 11, 2012, 10:20:53 am
content: Found these which look compact. Check out the wattage they provide:300W:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110754892289&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en1600W:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360439792248&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en1600W:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290681129168&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en2 last ones are cheaper, look smaller and have 1600W compared to large step down transformers which cost lot more and range from 150W - 500W that i saw.

author: G7PSK
author_rank: Super Contributor
timestamp: April 11, 2012, 10:36:16 am
content: Quote from: Boris_yo on April 11, 2012, 10:20:53 amNone of those are transformers. What you need is a transformer not a power adapter rated at least at 600 VA to allow for power surge on switch on. The primary rated at your home voltage and the secondary at 115 volts. one of these would do the trickhttp://www.ebay.co.uk/itm/New-110v-1-5Kva-Site-Transformer-output-x2-110v-16amp-/200597563607?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item2eb48be8d7#ht_1848wt_1185there are lots more on ebay what you need to type in for your search is "site transformer" any one will do as long as it has a large enough rating in other words above 600VA so the 1.5 KVA will work a treat but in all probability you might as well go fo a 3.5 KVA as you will get it for the same price.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: April 11, 2012, 11:23:17 am
content: Site transformer is needed if i work with power tool. Why would i need such big stuff for little cordless charger?Why this won't do:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360441048199&ssPageName=ADME:X:RTQ:US:1123#ht_3746wt_937This is similar but it clearly states that it is for DeWalt charger, although 200W:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130501941239&ssPageName=ADME:X:RTQ:US:1123#ht_3747wt_937Finally this is original charger but used however and intended for use in 220-240 electricity standard countries:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251030363583&ssPageName=ADME:X:eRTM:US:1123#ht_500wt_954

author: T4P
author_rank: Super Contributor
timestamp: April 11, 2012, 11:37:56 am
content: Those "compact" things are just glorified light dimmers . It's been said before .

author: Boris_yo
author_rank: Frequent Contributor
timestamp: April 11, 2012, 11:42:03 am
content: Quote from: Dave.S on April 11, 2012, 11:37:56 amRight, but manufacturers must state so because i hear a lot of people constantly running into shocks, fires etc. as they are misled. In fact people are being misled because seller wrote in description that this "dimmer" (2nd link) fits DeWalt charger.What do you think about used charger by the way (3rd link)? Worth the risk? eBay does not offer life insurance yet by the way.

author: T4P
author_rank: Super Contributor
timestamp: April 11, 2012, 11:47:09 am
content: Quote from: Boris_yo on April 11, 2012, 11:42:03 amUsed charger ... err ... hurr ... durr ... that seller has 99% rating

author: G7PSK
author_rank: Super Contributor
timestamp: April 11, 2012, 12:38:40 pm
content: Those things are only good for resitive loads for a minute or two like hair dryers and shavers etc. Your charger is either an inductive or capacitive load, I have one of those things that I bought when visiting the US as a curio and it is not much more than that. You must either get a European charger or a proper transformer or bin the power tool any thing else is asking for grief.

author: T4P
author_rank: Super Contributor
timestamp: April 11, 2012, 05:30:45 pm
content: It's a switching supply inside so the 200W only lasts for milliseconds while the Low ESR Caps charge up .

author: Boris_yo
author_rank: Frequent Contributor
timestamp: April 11, 2012, 06:24:44 pm
content: Quote from: Boris_yo on April 11, 2012, 11:42:03 amQuote from: Dave.S on April 11, 2012, 11:47:09 amCan you explain please? Is that good or bad in your opinion? I have seen sellers with 92% rating but compared to them, 99% is almost perfect.

author: T4P
author_rank: Super Contributor
timestamp: April 11, 2012, 07:18:42 pm
content: Go ahead and if anything goes wrong do the paypal thing .

author: SeanB
author_rank: Super Contributor
timestamp: April 11, 2012, 07:53:04 pm
content: The power supply is a simple step down converter, using an output that is connected directly to the rectified mains input. Best is to use an isolating transformer, the site transformers are common enough in Europe on work sites, so these will do the job. Voltage converters will make a lovely smoke generator.

author: T4P
author_rank: Super Contributor
timestamp: April 11, 2012, 08:05:40 pm
content: Quote from: SeanB on April 11, 2012, 07:53:04 pmNo .http://dewaltownersgroup.com/index.php?topic=869.0A site transformer is an extra load , he'd better get a used 220V dewalt charger instead .

author: IanB
author_rank: Super Contributor
timestamp: April 11, 2012, 08:18:29 pm
content: Quote from: Dave.S on April 11, 2012, 08:05:40 pmThe site transformer will be more generally useful for any other 120 V items that may also need power. The 220 V DeWalt charger would be more compact, but will be confined to just the one use.

author: G7PSK
author_rank: Super Contributor
timestamp: April 11, 2012, 09:00:05 pm
content: If you go round the larger building/construction sites you may be able to pick up a site transformer for free or a drink, many of them get condemned by the site safety officer due to the spring loaded socket caps getting knocked and broken nothing wrong with the transformer but no socket cap and they get slung into the skip.

author: T4P
author_rank: Super Contributor
timestamp: April 12, 2012, 08:43:02 am
content: Quote from: IanB on April 11, 2012, 08:18:29 pmCertainly yes . Big 'n heavy and he can put a heck more things then just a dewalt charger .