What type of transformer is this? How to find replacement? - Page 1
Forum section: electronics / repair

author: Jay112
author_rank: Regular Contributor
timestamp: June 26, 2021, 02:27:22 pm
content: This is for the control box for a pipe camera. Something was constantly blowing the 1-amp fuse on the input to the transformer. I disconnected everything from the output of the transformer to see if the transformer itself was blowing the fuse, and the fuse was still blowing, so there seems to be a problem with the transformer. As for the coils I'm getting 75 ohms on the blue/output side, and 11 ohms on the red/input side.The first picture is of the actual transformer, and the 2nd picture is a Google Translate of the text on the transformer.My question is: How is it labelled as 220v for both input AND output? What is it doing in that case?I tried searching for the model number but couldn't find anything that matched. So I'm wondering if I can find a replacement from a different manufacturer, but I don't know what to look for when the voltage on both input and output are the same.Thanks!

author: bdunham7
author_rank: Super Contributor
timestamp: June 26, 2021, 02:50:25 pm
content: What power source were you running it on when it started to blow fuses?

author: themadhippy
author_rank: Super Contributor
timestamp: June 26, 2021, 02:52:08 pm
content: QuoteTry isolating transformer,also instead of 30 watts 30VA might get more results

author: Jay112
author_rank: Regular Contributor
timestamp: June 26, 2021, 02:54:22 pm
content: I'm using the step-up transformer (120-220v) that came with the unit from the manufacturer. It's been running fine for over a year like this. The fuse first started tripping after the camera's cable ended up getting a hole in it while it was under water.Edit: sorry, this was in response to bdunham7

author: themadhippy
author_rank: Super Contributor
timestamp: June 26, 2021, 02:58:35 pm
content: Quoteseems a bit of a daft solution when a single 120-220v transformer would do the job,as long as its an isolating type and not an auto transformer

author: Jay112
author_rank: Regular Contributor
timestamp: June 26, 2021, 03:00:13 pm
content: Quote from: themadhippy on June 26, 2021, 02:58:35 pmIs it possible they do it like this because it was meant primarily for a non-USA market?

author: Ian.M
author_rank: Super Contributor
timestamp: June 26, 2021, 03:02:51 pm
content: That looks like it could be a split-bobbin isolation transformer. 220V in, isolated 220V out, and its only good for max 136mA. It also looks like its overheated enough to partially melt and distort its bobbin, which, if its load is some sort of wide input range switched mode PSU, could be due to running it on 115V which would double the current. A loose connection to your step-up transformer, disabling its boost, could also be the cause

author: Jay112
author_rank: Regular Contributor
timestamp: June 26, 2021, 03:04:05 pm
content: Sorry if this is a dumb question, but since there isn't actually any voltage change, then technically is it okay if I find a transformer that's even higher than 220v rating, as long as it can still handle around 30 watts? I'm having trouble finding a 220v-220v 30va, even when searching for "isolation transformer". Digikey didn't have any that were 220v-220v.

author: Jay112
author_rank: Regular Contributor
timestamp: June 26, 2021, 03:05:56 pm
content: Quote from: Ian.M on June 26, 2021, 03:02:51 pmI didn't notice at all that it was visually overheated. Thanks for all of the information. It's fused with only a 1-amp fuse, so the current draw you listed sounds logical.

author: bdunham7
author_rank: Super Contributor
timestamp: June 26, 2021, 03:25:54 pm
content: Quote from: Jay112 on June 26, 2021, 03:04:05 pmYes, you can use a 230VAC, 240VAC or something like that. You could also use a 240/120 VAC stepdown transformer in reverse and skip the external step-up transformer. If your existing step-up transformer is isolated (it probably isn't, unfortunately) you could use that.This should work if it fits:https://www.mouser.com/ProductDetail/Hammond-Manufacturing/185D230?qs=atHKiefXm7SM0lx%252BZUpNSQ%3D%3D

author: Jay112
author_rank: Regular Contributor
timestamp: June 26, 2021, 07:33:52 pm
content: This should work if it fits:https://www.mouser.com/ProductDetail/Hammond-Manufacturing/185D230?qs=atHKiefXm7SM0lx%252BZUpNSQ%3D%3DThank you very much!! The only other options I had seen were from China.

author: Jay112
author_rank: Regular Contributor
timestamp: July 03, 2021, 03:02:32 pm
content: Can you please look at this diagram and tell me which of the 2 secondary connection types I should choose if I'm running it at 230v? I'm curious to learn what are the differences between the series/parallel wiring. Is it just that the parallel is for 115v and series for 230v?

author: bdunham7
author_rank: Super Contributor
timestamp: July 03, 2021, 04:02:04 pm
content: What do you mean by 'running it at'?If you want the input or supply to be 230V (not sure why you would in NA....) then you put the primaries in series as shown.As for the outputs, I don't see voltages listed so I'd want that before advising what to do there.If this is exactly the 185D230 model that I posted before, and you want to have 115VAC in and 230VAC out to your device, then you would use the primary connection as shown on the left and the secondary as shown on the right.

author: Jay112
author_rank: Regular Contributor
timestamp: July 03, 2021, 04:15:12 pm
content: Quote from: bdunham7 on July 03, 2021, 04:02:04 pmThank you for responding. Yes, this is the 185D230 model. As a reminder, I'm doing 230VAC in and 230VAC out, and using it only for isolation.Do you think it's strange the way they wrote the diagram, without listing any output voltages? How do you think I should wire the secondaries if I have 230VAC in?

author: bdunham7
author_rank: Super Contributor
timestamp: July 03, 2021, 04:23:48 pm
content: For 230VAC isolation only, you use both connections as shown on the right. The reason they don't list secondary voltages are that the 185 series is made with a variety of output voltages and the diagram covers all of them.

author: Jay112
author_rank: Regular Contributor
timestamp: July 03, 2021, 04:24:48 pm
content: Quote from: bdunham7 on July 03, 2021, 04:23:48 pmThank you!!

author: Ian.M
author_rank: Super Contributor
timestamp: July 03, 2021, 06:20:28 pm
content: OTOH it may well be possible to wire the new transformer to run from 115V, replacing both the bad transformer and the external stepup transformer. If the stepup transformer *only* feeds this unit, and *nothing* taps off 230V mains power before this transformer, you could use the 115V primary wiring diagram, swap out the fuse for a 2A one and put a US plug on the lead.

author: james_s
author_rank: Super Contributor
timestamp: July 03, 2021, 06:26:59 pm
content: Quote from: Jay112 on June 26, 2021, 03:04:05 pmA higher voltage transformer is better to a point, it will be less likely to saturate. With a 1:1 turns ratio you will have a 1:1 voltage ratio, the upper limit is the voltage at which the iron core starts to saturate and then it will get very hot. It would not surprise me if the original fault is due to running a 220V rated transformer that was probably built very marginally with less than the ideal amount of wire and iron in it on 240V.

author: fzabkar
author_rank: Super Contributor
timestamp: July 04, 2021, 06:49:51 pm
content: If the 120V-220V step-up transformer provides the required isolation, then why do you need the 220V-220V transformer at all? Why not simply bypass it with wire links (or fuses) from primary to secondary?

author: james_s
author_rank: Super Contributor
timestamp: July 04, 2021, 06:51:39 pm
content: Quote from: fzabkar on July 04, 2021, 06:49:51 pmDoes it? I would not make that assumption unless it has been confirmed. The vast majority of 120/240 step-up transformers are autotransformers which do NOT provide isolation.

author: fzabkar
author_rank: Super Contributor
timestamp: July 04, 2021, 09:06:08 pm
content: Quote from: james_s on July 04, 2021, 06:51:39 pmPoint taken, but the OP hasn't even bothered to investigate this possibility. By the way, I have seen very few autotransformers. In my opinion they should be avoided. Clearly the manufacturer's philosophy is focussed on safety, so an autotransformer would seem to be an inconsistent choice as an accessory for a product that incorporates an isolation transformer.

author: james_s
author_rank: Super Contributor
timestamp: July 04, 2021, 11:06:51 pm
content: Quote from: fzabkar on July 04, 2021, 09:06:08 pmI have seen lots of autotransformers, I have at least five of them, a few operating various foreign devices and a couple of them for bench testing, there's nothing wrong with them, they work perfectly fine and are the standard method of stepping up/down line voltage. An autotransformer is more efficient both electrically and in materials than a conventional transformer and the lack of isolation is frequently acceptable.Why take the chance? Unless you KNOW the transformer provides adequate isolation it's best to not rely on it when dealing with something that is used in/around water. Why would an autotransformer be inconsistent or inappropriate as an accessory? It's a 220V device that includes an internal safety isolation transformer. The step-up transformer is an add-on to allow it to be used in a 120V region, the device already has an isolation transformer so IMO an autotransformer is the appropriate device to provide the required voltage. If it is ever operated from a 240V supply it will still need the internal isolation transformer.

author: ambrosia heart
author_rank: Regular Contributor
timestamp: July 05, 2021, 03:34:25 am
content: For foreigners, buying a transformer is very expensive.If you have friends living in Hong kong, ask them for help.https://www.aliexpress.com/item/4000225709023.html?spm=a2g0o.productlist.0.0.54c3802fh4aJVT&algo_pvid=898f069f-1153-4519-936f-a2bf01fccef5&algo_exp_id=898f069f-1153-4519-936f-a2bf01fccef5-32This one is 220V to 110V. you can plug in 100V directly, so that 200V will get.电源变压器 = power transformer.输入 = input 紅-紅 = RED-RED输出 = output 蓝-蓝 = blue-bluehttps://www.aliexpress.com/item/32885767943.html?spm=a2g0o.productlist.0.0.23ce18c9tFEtak&algo_pvid=2dd5662d-4be9-4e9a-a617-60195c6fcc6f&algo_exp_id=2dd5662d-4be9-4e9a-a617-60195c6fcc6f-0This one is 220V to 220V输出 = output 绿-绿 = green-greenFor me, buy at taobao at cheap price.https://item.taobao.com/item.htm?spm=a230r.1.14.254.68a34f5a0Ck4Pr&id=638465386315&ns=1&abbucket=18#detail30VA输入 = input 紅 = RED输出 = output 蓝 = blue30RMB = 4USDhttps://detail.tmall.com/item.htm?spm=a230r.1.14.91.68a34f5a0Ck4Pr&id=20009470128&ns=1&abbucket=18&skuId=459408992260630W 220V转110V = 220V to 110V (you can plug in 100V directly , the voltage will be lower than 220V)30W 220V转220V = 220V to 220V输入 = input 紅 = RED输出 = output 蓝 = blue35RMB = 4.5USD