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 Post subject: Boost Transformer in Japan
PostPosted: Jan Sat 06, 2018 7:38 pm 
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Joined: Oct Tue 16, 2012 12:53 am
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I need to put together a few boosting transformers to go from 100V to 115V or thereabouts supplying US spec vintage tube gear in Japan. I would like a 20Amp transformer, but what I have found is one pricey option, one cheap, both at lower current ratings.

First question: The Hammond listed here:
https://www.mouser.com/ProductDetail/Ha ... %2Fw%3D%3D

It has an 8A rating, and a 100VA rating as listed by Mouser and the Hammond spec sheet. I am confused and forgive a stupid question, but shouldn’t that be more like 1000VA?

Do you think I should look for something more like a 14V secondary for my application?

The other option, which is cheap is this:
http://www.surpluscenter.com/Brands/Tod ... 5-1169.axd

A “15V voltage booster.” I found that posted by a user on this forum somewhere when I was researching the topic. Looks like it could be repackaged into a grounded box with a fuse, etc., easily. Claimed rating is 6.4A, so it might not be robust enough to handle my 32V2 transmitter, at 5A, probably my heaviest load.

One other point, the line frequency in my part of Japan is 50Hz, but I believe this isn’t of major consequence in my situation. Tell me if I am wrong.

Your opinions and expertise would be much appreciated.
:D


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sat 06, 2018 7:42 pm 
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Line frequency is critical to transformer health!

Any power transformer rated for 60 cycles will overheat significantly if operated from a lower frequency to the point of burning up in some cases. You may need to operate at a lower voltage so it doesn't get too hot and melt down. The transformer in your equipment will be at risk unless it's rated for 50Hz if you are planning to run it at rated line voltage.

If you are planning to use a boost transformer on 50Hz, it MUST be a 50Hz transformer.

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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sat 06, 2018 7:48 pm 
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Location: Annapolis, MD
12.6 volts at 8 amps is in fact 100.8 VA

The voltage ratio is 115 / 12.6 = 9.1. If wired to a 100-volt line--in a boost configuration-- you'll get 100 + 9.1 = 109.1

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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sat 06, 2018 10:32 pm 
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Joined: Aug Thu 27, 2009 7:47 am
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Location: Seattle 98125
A little more expensive, but there's also these transformers with 100V input and 115/120V output.

https://www.mouser.com/Power/Transforme ... =Pricing|0


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 12:18 am 
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Joined: Jan Tue 16, 2007 7:02 am
Posts: 2588
Location: Lexington, KY USA
Does not Japan still have both 50Hz and 60Hz power, depending on the region?

And are not transformers to be had in Japan? US sourced iron will be costly to ship.

If you are trying to run a 60Hz transformer powered radio off a 50Hz line, 100V might be pretty OK, if the radio works at the lower voltage.

Ted


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 1:01 am 
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Joined: Dec Sun 14, 2008 3:33 pm
Posts: 733
Location: Tokyo
Japan has both 50Hz and 60Hz areas. Naturally, appliances here are designed to run on either.

Simple tube radios (AA5s, S38, etc), without VR, run fine on 100VAC. They take longer to warm up, but they work fine. People here have told me they're still using the original tubes in their vintage US-made 1950s and 60s receivers. Again, simple designs.

Step-up transformers are available here. The cheaper ones are auto-transformers. Here's a link to Amazon Japan:

https://www.amazon.co.jp/

You can also search for them on the internet using this term:

昇圧トランス 120v

Pronounced 'shiyoo atsu toransu'.

Rob


Last edited by shinkuukan on Jan Sun 07, 2018 9:45 am, edited 1 time in total.

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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 6:10 am 
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Joined: Oct Tue 16, 2012 12:53 am
Posts: 15
Thanks, Dennis, I will change my requirements to include 50Hz in the spec. for the boost transformer. Most of the old ham gear I have is claimed by the manufacturer to operate at 50/60Hz.
Mr. Detrola wrote:
Line frequency is critical to transformer health!

Any power transformer rated for 60 cycles will overheat significantly if operated from a lower frequency to the point of burning up in some cases. You may need to operate at a lower voltage so it doesn't get too hot and melt down. The transformer in your equipment will be at risk unless it's rated for 50Hz if you are planning to run it at rated line voltage.

If you are planning to use a boost transformer on 50Hz, it MUST be a 50Hz transformer.


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 6:12 am 
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Joined: Oct Tue 16, 2012 12:53 am
Posts: 15
Thanks, Mark, I see that's a little low. Will have to keep looking.
pixellany wrote:
12.6 volts at 8 amps is in fact 100.8 VA

The voltage ratio is 115 / 12.6 = 9.1. If wired to a 100-volt line--in a boost configuration-- you'll get 100 + 9.1 = 109.1


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 6:32 am 
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Joined: Oct Tue 16, 2012 12:53 am
Posts: 15
Thank you! This series does what I need in voltage (100 to 115 step up) and have a 50Hz rating. But since these are step up and not used as a boost autotransformer, I believe the secondary current rating is too low unless I got the massive 22lbs unit. I am not clear on that. Please set me straight. (My heaviest single load draws 5A, but I would like to add a receiver or two.) I put in a query to Antek torroidal in NJ to see how much they would charge to build one and how much it would weigh.
jkoebel wrote:
A little more expensive, but there's also these transformers with 100V input and 115/120V output.

https://www.mouser.com/Power/Transforme ... =Pricing|0


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 6:39 am 
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Joined: Oct Tue 16, 2012 12:53 am
Posts: 15
Yes, Ted, Japan is splitsville on power frequency. I live in Tokyo where it is 100V at 50Hz. I am in the US right now briefly for the holidays so I am taking the opportunity to try to figure this out and maybe take something back. My Japanese is not great at all so rooting around Akihabara with a mission is not simple, especially when you have to ask for a technical spec. :oops: And worse if you aren't sure what will work.
Usually Lurking wrote:
Does not Japan still have both 50Hz and 60Hz power, depending on the region?

And are not transformers to be had in Japan? US sourced iron will be costly to ship.

If you are trying to run a 60Hz transformer powered radio off a 50Hz line, 100V might be pretty OK, if the radio works at the lower voltage.

Ted


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 6:54 am 
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Joined: Oct Tue 16, 2012 12:53 am
Posts: 15
Thanks, Rob. Imagine that I am like a vintage radio guy in the US, I want to run my vintage gear no higher than about 115V. However I also have modern US spec electronics. I see that some of the transformers shown in the Amazon link you provided have 110 and maybe 120V secondaries (not sure what the "~" in "110~120" means.) So I will look into these with the help of a native speaker.

shinkuukan wrote:
Japan has both 50Hz and 60Hz areas. Naturally, appliances here are designed to run on either.

Simple tube radios (AA5s, S38, etc), without VR, run fine on 100VAC. They take longer to warm up, but they work fine. People here have told me they're still using the original tubes in their vintage US-made 1950s and 60s receivers. Again, simple designs.

Step-up transformers are available here. The cheaper ones are auto-transformers. Here's a link to a page from Amazon Japan:

https://www.amazon.co.jp/s/?ie=UTF8&keywords=昇圧トランス+120v&tag=googhydr-22&index=aps&jp-ad-ap=0&hvadid=217403914017&hvpos=1t1&hvnetw=g&hvrand=7334434989279252521&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1009461&hvtargid=kwd-51998620351&ref=pd_sl_7gmkyus1zu_e

You can search for them on the internet using this term:

昇圧トランス 120v

Pronounced 'shiyoo atsu toransu'.

Rob


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 10:03 am 
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Joined: Dec Sun 14, 2008 3:33 pm
Posts: 733
Location: Tokyo
'110~120' means the actual output voltage will vary with the load you put on the transformer.

These are, btw, autotransformers, so there is no isolation between input and output.

They are a fairly common item here. Large electrical appliance stores, Yodobashi Camera, Bikku Camera, etc
usually have them in stock. You don't have to go to Akihabara. As you must have noticed, they're not
particularly cheap ($100~$150). But they are well made (traditional Japanese quality, not imported from China)
and you can turn them around to run any 100VAC Japanese stuff you buy here in the States.

As you know, Tokyo power is 50Hz. If any of your equipment must run on 60Hz, it's not going to
work here.

Rob


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 6:47 pm 
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Joined: Oct Tue 16, 2012 12:53 am
Posts: 15
Let me ask you this, then, if I desire 115V, you are saying there is no way to acheive that reliably with an autotransformer boost configuration? Because I do own 2 Variacs, but I'd rather not use those in a permanent installation.

shinkuukan wrote:
'110~120' means the actual output voltage will vary with the load you put on the transformer.

These are, btw, autotransformers, so there is no isolation between input and output.

They are a fairly common item here. Large electrical appliance stores, Yodobashi Camera, Bikku Camera, etc
usually have them in stock. You don't have to go to Akihabara. As you must have noticed, they're not
particularly cheap ($100~$150). But they are well made (traditional Japanese quality, not imported from China)
and you can turn them around to run any 100VAC Japanese stuff you buy here in the States.

As you know, Tokyo power is 50Hz. If any of your equipment must run on 60Hz, it's not going to
work here.

Rob


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 8:18 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 882
Location: Wayside, NJ Monmouth
I have built Bucking transformers for my tube Ham radio. But I went with this for my work bench. The Variac came from my job. It was one third of a 0 - 208 three phase power station. One of the units failed, so I got the other two. I run my whole bench on this. It has input and output circuit breakers, Voltmeter, Ampmeter, RFI filtering on the input and output, and last a run time meter. Put it in because I had one.


Attachments:
VAR05.JPG
VAR05.JPG [ 96.98 KiB | Viewed 1256 times ]
VAR04.JPG
VAR04.JPG [ 110.85 KiB | Viewed 1256 times ]
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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 8:43 pm 
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Joined: Sep Thu 23, 2010 6:37 am
Posts: 10267
Location: Powell River BC Canada
I have some large 100/120 transformers.

They were made in Japan, and accompanied some very special
lab apparatus, made for the pulp and paper industry.

So a source may be sites that sell things specially marketed
in that industry.

On such site I found my Induktor, A Swedish made electrical
instrument that appeared in paper maker motor shops.

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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Sun 07, 2018 9:39 pm 
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Joined: Oct Tue 16, 2012 12:53 am
Posts: 15
The runtime meter is the pièce de résistance! I may end up shipping over my variacs. Have to keep that big knob behind a security cover.
N2LXM wrote:
I have built Bucking transformers for my tube Ham radio. But I went with this for my work bench. The Variac came from my job. It was one third of a 0 - 208 three phase power station. One of the units failed, so I got the other two. I run my whole bench on this. It has input and output circuit breakers, Voltmeter, Ampmeter, RFI filtering on the input and output, and last a run time meter. Put it in because I had one.


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Mon 08, 2018 1:10 am 
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Joined: Dec Sun 14, 2008 3:33 pm
Posts: 733
Location: Tokyo
If you must have a consistent 115VAC, then I think you'll need to bring one of your Variacs.

Homes and apartments in Japan are, from an American perspective. electrically underpowered. I
once lived in a rather nice Tokyo apartment that was limited to just 3KW! That's not unusual.
As you switch your toaster, washing machine, space heater, etc on and off, your voltage will change.
(And btw, don't assume just because your AC wall socket has three prongs it has a functioning
ground. Japan used a two wire system until fairly recently. Sometimes the ground lug is left
unconnected because there's nothing to attach it to).

Have you lived here before? Homes and apartments cannot be described as spacious. No garages
or basements to serve as work rooms or storage. There's a reason Japanese manufacturers are
world leaders in miniaturization.

EDIT: my wife tells me that apartment was originally fused to just 24A/100VAC. We paid extra to have it raised to 30A.

Rob


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Mon 08, 2018 8:20 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 19167
Location: Warner Robins, GA
One option if you need steady 115Vac is to get one of those voltage regulating transformers provided one is made for 50Hz and can handle the load of your transmitter.


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Tue 09, 2018 9:39 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2200
Location: Saskatoon
Here's what you need.
Attachment:
Generator.jpg
Generator.jpg [ 57.42 KiB | Viewed 1133 times ]

Put it on the patio, and hope the neighbours don't complain. :)


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 Post subject: Re: Boost Transformer in Japan
PostPosted: Jan Tue 09, 2018 2:01 pm 
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Joined: Dec Sun 14, 2008 3:33 pm
Posts: 733
Location: Tokyo
Sky, I didn't notice that you wrote you live in Japan. So you're familiar with both the space and
electric power limitations.

If you don't find what you want in the States, just remember you can get it here.

Rob


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