220v to 110v transformer - Page 1
Forum section: electronics / general

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 02:27:50 pm
content: Sup guys, today i just bought a transformer for my Hakko FX-888D which converts 220VAC to 110VAC. The hakko manual says that it needs 120V however the transformer outputs 110V and i capable of providing 100W. Is there any problem with this 10V difference?Here is an image of the unit:You guys having more experience than me how does it look? Is that how a trsnformer should look like?

author: corrado33
author_rank: Frequent Contributor
timestamp: April 20, 2015, 02:51:22 pm
content: There's no problem with the 10V difference between the output of the transformer and what the haxxo "wants."Anything that's passed any sort of certification will be able to run on anything around 110V (barring some electric motors), as that's the voltage most of us have in our outlets (in the US.) It all depends on how far you are from the circuit breaker and whether or not you're using one leg from 3 phase power or not.In other words, you'll be fine.

author: Rufus
author_rank: Super Contributor
timestamp: April 20, 2015, 03:12:43 pm
content: The mains in Greece is nominally 230v anyway isn't it?

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 03:17:46 pm
content: Quote from: Rufus on April 20, 2015, 03:12:43 pmYes. It ranges from 220 to 240

author: Zero999
author_rank: Super Contributor
timestamp: April 20, 2015, 03:21:47 pm
content: The transformer's case should be earthed of course and it's good idea to check the continuity to be sure.The frequency is also slightly lower in Europe and the lower voltage will make it easier on the Hakko's transformer.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 03:36:15 pm
content: Quote from: Hero999 on April 20, 2015, 03:21:47 pmHow can i earth the case?The transformer has this crapy plug

author: corrado33
author_rank: Frequent Contributor
timestamp: April 20, 2015, 03:45:30 pm
content: Quote from: FlevasGR on April 20, 2015, 03:36:15 pmPhysically? Take a wire, attach it with a nice star washer to the case, then attach it to a long metal pole and hammer the pole into the ground. Then it has been "earthed."Alternatively, (If and only if you know what you are doing.) connect it to the earth wire in your walls... (carefully.) (However, I do not know if where you are HAS earth wires in the house wiring.)

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 03:49:50 pm
content: Is there any problem if i live it like that? Since i will have only the Hakko on what can go wrong?

author: Zero999
author_rank: Super Contributor
timestamp: April 20, 2015, 03:57:45 pm
content: It's nothing to do with the Hakko. The problem is the transformer could develop a fault and its case could become connected to the phase conductor.The correct solution is to change to a three core cable and three pin plug.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: April 20, 2015, 03:59:27 pm
content: Quote from: FlevasGR on April 20, 2015, 03:49:50 pmOh boy, now ya done it. You just asked the infamous question.On a more serious note if you dont ground the case you can get a build up of charge, which can then discharge upon someone touching it.As said directly above me while I was typing this.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 04:10:55 pm
content: Every wall socket on my house has an earth connection. If i do what corrado33 said with the 3 core wire and then attach the ground wire on the case would be okay? I was thinking to buy a big project box and a US wall socket and connect them all together.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 05:02:50 pm
content: Quote from: FlevasGR on April 20, 2015, 04:10:55 pmThis is what i'm talking about:

author: SeanB
author_rank: Super Contributor
timestamp: April 20, 2015, 05:28:42 pm
content: Just be careful in that the transformer will have one output connected to the one line lead, so the output could be 110VAC with the one lead connected to neutral, or 110VAC with the one side riding on 220VAC.

author: corrado33
author_rank: Frequent Contributor
timestamp: April 20, 2015, 06:09:31 pm
content: Quote from: Hero999 on April 20, 2015, 03:57:45 pmYes, this is the correct solution. While what you have above would work fine, the correct way to do it is to switch both the input and output 2 core wires to 3 core wires and connect the earth ground (of both input and output) to the case on the inside of the device with a star washer. It would also be the cleanest in my opinion.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 06:17:15 pm
content: Quote from: corrado33 on April 20, 2015, 06:09:31 pmThis is what i want to do. I just seperated the wires on the "DaveCAD" to make it easier to see. I hope nothing explodes...

author: Zero999
author_rank: Super Contributor
timestamp: April 20, 2015, 06:23:57 pm
content: Quote from: SeanB on April 20, 2015, 05:28:42 pmThat will only be the case if it's an autotransformer. It's quite likely though it's an isolation transformer. This is easy to test by checking the continuity between the primary and secondary.: if it's an isolation transformer, it'll be open circuit.

author: SeanB
author_rank: Super Contributor
timestamp: April 20, 2015, 07:09:11 pm
content: The one shown is an autotransformer, there are 2 varieties I have met. the first is a 220v winding with a centre tap, and the other is a 55VAC, 110VAC,55VAc winding variant. The first will either have the one side at neutral or line voltage and the other wire 110V offset from that, the second will always have 55VAC on one leg and the other at 165VAC, giving 110VVAC between them.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 08:59:40 pm
content: I'm confused nowWith a short answer can i do what i described or i will burn my house down?

author: corrado33
author_rank: Frequent Contributor
timestamp: April 20, 2015, 09:11:10 pm
content: Quote from: FlevasGR on April 20, 2015, 08:59:40 pmYes. What you have should work fine. In fact most newer versions of what you have are probably wired like you have. They were just discussing the possible differences of what's inside the transformer.

author: Zero999
author_rank: Super Contributor
timestamp: April 20, 2015, 09:53:14 pm
content: Quote from: SeanB on April 20, 2015, 07:09:11 pmHow do you know the one shown is an auto transformer? Do you have x-ray spectacles or something?It's more likely it's an isolation transformer, especially given its size which is quite large for an autotransformer, which would be half the size for the same power rating and the fact the connections to the primary and secondary are on opposite ends of the case.Quote from: FlevasGR on April 20, 2015, 08:59:40 pmWhat you've drawn is fine.In addition to that, if it's an autotransformer, it's important you've got polarity of the the phase and neutral correct on the primary, otherwise the secondary will float at 220V.An auto transformer only has one winding. The neutral should be connected to the common connection which goes straight through to the load. If the phase is connected to the common instead, the voltages on the secondary will be 220V (which should be 0V) and 330V (instead of 110V). This wouldn't blow up the soldering iron but it would put extra strain on the insulation and could pose a shock risk if something goes wrong inside the iron.On the other hand, if it's an isolation transformer it will have two separate windings, so polarity of the connections is not critical.It should be obvious whether you've got an isolation transformer or an autotransformer when the cover is removed. An autotransformer will only have three connections to the windings. An isolation transformer will have four connections: two for the primary and two for the secondary. This is assuming of course there aren't any other taps or windings for different voltages.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 20, 2015, 10:40:30 pm
content: Since it has this plug which is easy to reverse the polarity each time and since its a plug and play system is there any posibility to be an autotransformer? I could mesure it to see the output voltage. I haven't done that mostly because i'm scared as hell when im probing mains

author: Zero999
author_rank: Super Contributor
timestamp: April 21, 2015, 07:52:38 am
content: There is no need to probe the mains. With the transformer unplugged, measure the resistance between the one of the pins of the US socket and the mains lead. Hopefully it'll read open circuit.Ideally if you fit a three pin plug, you won't be able to reverse the polarity.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 21, 2015, 01:42:14 pm
content: I mesured the resistance. It's an open circuit but the resistance changes depending on which pin i connected the proble of the multimeter. One pin gives 0? and 6? and se second pin gives55? and 49?

author: SeanB
author_rank: Super Contributor
timestamp: April 21, 2015, 06:52:19 pm
content: It is an autotransformer with the one side of the 110V output connected to the line, and the other side of the 110V connected to the centre tap. thus depending on how you insert the plug it will either be 110VAC floating on 220VAC or 110VAC referenced to ground. Will work with the soldering station but just do not think that the output is only 110V, it is going to be as dangerous as 220V mains.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 21, 2015, 09:19:38 pm
content: Quote from: SeanB on April 21, 2015, 06:52:19 pmOfcurse i know it's as dangerus as the 220v. So i dont have to worry in which way i will plug the station right?

author: babysitter
author_rank: Frequent Contributor
timestamp: April 22, 2015, 05:04:12 am
content: Take care of the "polarity" - I nailed a autotransformer into a 110V device to run it in germany but I always check the "polarity" of the unpolarized Schuko plug. When your autotransformer gives you 110V and 220V on the "hot" wires, you have the correct voltage between the hot ones, but one with 220V against PE - which might be too much for the isolation.

author: FlevasGR
author_rank: Regular Contributor
timestamp: April 22, 2015, 05:13:40 pm
content: Quote from: babysitter on April 22, 2015, 05:04:12 amIn case the polarity is wrong i can always probe it with a multimeter to check the voltages right?

author: babysitter
author_rank: Frequent Contributor
timestamp: April 23, 2015, 04:33:32 am
content: Yeah, just check the output of your autotransformer vs. earth, it shall be 0V and 110V relative to ground. You might mark your relevant mains sockets and plugs accordingly, normally it should be the same direction in the house. Put the mains plug so that the common connection of the autotransformer connects to the neutral wire which should be 0V against earth.If you are afraid of exploding multimeters - like almost everybody here - use a contactless voltage probe to find the hot wire.

author: Zero999
author_rank: Super Contributor
timestamp: April 23, 2015, 07:39:24 am
content: Just fit a three pin which you should do anyway to provide an earth connection and problem solved.

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 13, 2015, 12:42:17 pm
content: After 4 weeks its finally here!So i took apart the transformer to see if its an autotransformer or a normal transformer. Here you can see the pics:

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 13, 2015, 01:53:36 pm
content: 1) Most certainly replace the input cord with a proper grounded version, and connect the green-wire safety ground firmly to the transformer core using one of those bolts in the corners. This protects you from any possible fault in the "pre-owned" transformer.2) It appears from the resistance measurements that you have an auto-transformer, and not an isolation transformer.3) I am assuming that your country uses that goofy symmetrical mains plug that allows you to plug it in either way around.4) The combination of (2) and (3) above means that the OUTPUT of the auto-transformer has indeterminate potential from the "neutral" terminal vs. ground.5) Assuming your soldering station is fitted with a North-American style NEMA mains power plug/cord.The NEMA standard assumes that the round pin is connected directly to green-wire safety ground. Clearly this should be a direct extension of the green-wire safety ground from the mains source that supplies the step-down auto-transformer.It also assumes that the "neutral" (old school: white, euro: blue), wider blade is at essentially "ground" potential. In practice, it may be a volt or two above ground, but the neutral wire is actually connected to green-wire ground back at the circuit-breaker distribution panel.The "hot" or "live" or "phase" pin (old school: black; euro: brown) is at the rated mains voltage which is typically between 110 and 120V AC @ 60 Hz.Because of (2) and (3) above, that means that you have no assurance that the NEMA "neutral" pin is really at near-zero volts. Because if you plug in the 230V mains plug "backwards", then the voltage on the "hot" and "neutral" NEMA pins will be backwards. Now in a proper, modern, grounded or double-insulated gadget, maybe that won't make a significant difference.But CERTAINLY you want to make sure that the green-wire safety ground is passed all the way through from the mains wall-socket all the way into the soldering station.It is also not clear whether the solder station is "hard-wired" for use at 60 Hz, or whether it will work OK at 50 Hz? They could have designed it to work properly at either supply frequency. This very question has been discussed several times in these forums, but I can't remember ever seeing definitive reports of compatibility (or not) with 50 Hz.So why does it seem so popular to use 115V 60Hz Hakko gear in 230V 50Hz territories? Don't they make proper 230V 50Hz models?

author: IanB
author_rank: Super Contributor
timestamp: May 13, 2015, 01:58:30 pm
content: Quote from: Richard Crowley on May 13, 2015, 01:53:36 pmThey do, but it seems that the usual selling price is twice as much in 230 V territories

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 13, 2015, 02:25:11 pm
content: If that is a 2-prong output plug on the 110V side, I would disconnect and even remove it. It would NOT be safe to plug in a proper modern grounded load (like the Hakko soldering station) to an ungrounded socket of indeterminate polarity.

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 13, 2015, 02:46:53 pm
content: Quote from: IanB on May 13, 2015, 01:58:30 pmExactly. The 220v version i way more expensive and harder to find.Pretty much i'm gonna return this uint back and get a proper converter.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 13, 2015, 03:41:33 pm
content: Quote from: FlevasGR on May 13, 2015, 02:46:53 pmYou probably have your government(s) (including the EC) to thank for that.Between trade tarrifs and "certification", etc. that probably accounts for the significant price difference.It is hard to imagine that the 230V version is any more expensive to actually make than the 115V version.QuoteYou could make that one work.I would replace the input cord/plug and the output connector.I would also install a light or buzzer or something to alert you that it was plugged in "backwards" because of your goofy symmetrical euro-plug.For better or worse (you can argue both ways) it appears from previous similar discussions that the Euro-standard is to treat both of the main power pins as "hot" and assume that they are BOTH 100s of volts above ground. Which I believe is the argument for the symmetrical plug.

author: IanB
author_rank: Super Contributor
timestamp: May 13, 2015, 04:24:43 pm
content: Quote from: Richard Crowley on May 13, 2015, 03:41:33 pmEven in the UK where Live is 240 V above Earth and Neutral is tied to Earth at the supply, devices with the standard three pin grounded plug are still expected to treat L and N equally and provide full isolation/insulation for both.

author: Zero999
author_rank: Super Contributor
timestamp: May 13, 2015, 05:18:48 pm
content: Quote from: IanB on May 13, 2015, 04:24:43 pmYes, however protection devices such as fuses should always be on the live side whenever possible.In this case it's even more hazardous since a 110V device may not have the same standard of insulation as something designed for 230V operation.

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 13, 2015, 05:34:01 pm
content: Sure enough i'm not a professional but why the hell do we have 220V and 110V? Both work equaly good in every country like USA for the 110 and europe for the 220 so why is that voltage difference? We could all use 110 and live happily ever after.

author: helius
author_rank: Super Contributor
timestamp: May 13, 2015, 05:42:27 pm
content: The difference is historical, but one benefit to higher voltage mains is lower losses (or, smaller diameter cables for the same loss). Another is a stronger magnetic field in small induction motors, which gives them more power.

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 14, 2015, 09:32:12 am
content: I found this crap for 35 euros.Specs:300W 220V AC TO 110V AC And vice-versaInput Voltage AC 110/220VFuse protectionRed LED // Kick-ass feature....Built-in Voltage selectionInput plug: ET. AT. BS. SAAIt looks okay but you're the experts here

author: deian
author_rank: Newbie
timestamp: May 14, 2015, 10:18:29 am
content: I just bought a Hakko 888 from batterfly, and I made a comparison with tequipment. I paid 33% more(~45$) mainly due to 24% VAT in Romania. And that is without considering shipping, but my consolation is that I won't be messing around with step-down converters. We have this kind of converters at work and they are getting very hot.Good luck with finding one that works for you!

author: george graves
author_rank: Super Contributor
timestamp: May 14, 2015, 10:35:43 am
content: Quote from: FlevasGR on April 20, 2015, 05:02:50 pmI totally approve of this new DaveCad Lite. Well done.

author: nanofrog
author_rank: Super Contributor
timestamp: May 14, 2015, 01:24:50 pm
content: Quote from: FlevasGR on May 14, 2015, 09:32:12 amIt'll do the job (grounded =).Shouldn't run hot either at only 80W max drawn from it.

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 20, 2015, 02:58:58 pm
content: It came. However its not grounded on the back. Is it safe to plug the soldering station?

author: nanofrog
author_rank: Super Contributor
timestamp: May 20, 2015, 03:05:02 pm
content: Quote from: FlevasGR on May 20, 2015, 02:58:58 pmNot quite sure what you mean (ground screw, ... ?).Is the power cord you plug into the wall grounded?Photos should help.

author: Asmyldof
author_rank: Regular Contributor
timestamp: May 20, 2015, 03:05:20 pm
content: If you want a grounded iron (many, if not most, people do for ESD reasons), you'll need to apply ground to it yourself.Other than that, not having a ground internally connected, if it's rugged plastic on the outside, don't worry too much about that.

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 20, 2015, 03:10:00 pm
content: Quote from: nanofrog on May 20, 2015, 03:05:02 pmHere ya go:

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 20, 2015, 03:13:34 pm
content: What does "not grounded on the back" mean?What is a photo of the TOP of the unit supposed to show us?Can't really tell from your ambiguous photo whether the plug is 2-pin symmetrical, or 3-pin grounded?

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 20, 2015, 03:23:24 pm
content: Quote from: Richard Crowley on May 20, 2015, 03:13:34 pmThe plug which goes to the transformer is not grounded.The plug is 2pin symmetrical

author: Tandy
author_rank: Frequent Contributor
timestamp: May 20, 2015, 03:26:54 pm
content: I'm surprised that the soldering station is voltage specific. These days most equipment is universal.

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 20, 2015, 03:30:51 pm
content: Quote from: Tandy on May 20, 2015, 03:26:54 pmYeah i know. And it was harder to get the 220V verion of the fx-888d

author: IanB
author_rank: Super Contributor
timestamp: May 20, 2015, 03:57:16 pm
content: Quote from: Tandy on May 20, 2015, 03:26:54 pmThe FX-888 has a regular iron cored transformer inside it, no SMPS. Also, presumably for cost reasons, the transformer does not have multi-voltage taps. Each unit is specific to the region where it is sold.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 20, 2015, 03:59:14 pm
content: Quote from: Tandy on May 20, 2015, 03:26:54 pmI opened up my FX-888D and it looks like the mains power input PC board was originally made for 115/230V transformers, but they are using only single-winding transformers, so the dual-voltage parts of the board are unused. Strange.

author: FlevasGR
author_rank: Regular Contributor
timestamp: May 20, 2015, 05:27:00 pm
content: Everything worked fine! I'm soldering right now a board i'm making and the iron is pretty good. Day and nigh compared with my 5$ iron...