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Japanese mains voltage level?

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Flyback

Well-Known Member
Google says that Japanese mains voltage is 100VAC. Though obviously there will be some tolerance. Is it possible that Japanese mains could be at 85VAC for a few hours each day?
 

Flyback

Well-Known Member
The following PSU (HRPG-600-48) is 624W rated but from the graph on page 2 of its datasheet, it only supplies 548.8w according to your kindly provided -10% value of 90VAC.
The problem is that the graph is for the case of 60Hz mains, and the case of 50Hz mains will be worse, do you know how much worse it will be for 50Hz mains?

HRPG-600-48 PSU datasheet
http://www.meanwell.com/search/HRPG-600/HRPG-600-spec.pdf
 

jpanhalt

Well-Known Member
Most Helpful Member
Why do you think it needs to be derated differently for 50 Hz? I could not find a comment in the data sheet to that effect. Perhaps the input filter design is sufficiently robust so it won't matter. Anyway, you are asking a very specific design question about a particular product. Has the manufacturer responded to you on that question?

John
 

Flyback

Well-Known Member
yes meanwell now say 50/60hz is pretty much the same for their offline smps. I was slightly confusing it with mains transformers.
 

Flyback

Well-Known Member
JpanHalt:
thanks for your linked document, which says Japan mains is 100VAC +/-10v.....but our senior engineer tells us that Japan mains will virtually never be 10v down...he reckons its +/-5V and no more....who do we believe?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
JpanHalt:
thanks for your linked document, which says Japan mains is 100VAC +/-10v.....but our senior engineer tells us that Japan mains will virtually never be 10v down...he reckons its +/-5V and no more....who do we believe?
Are you really serious? - the SPECIFICATION is +/-10V (+/-10%) - in practice it's likely to be considerably better than that.
 

Flyback

Well-Known Member
thanks but our equipment runs 12 hours solid per day, if the supply drops out for just a few seconds (goes down to 90VAC for just a few seconds per day) then we get sheets of non cured ink going through the machine, which really is not wanted.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
thanks but our equipment runs 12 hours solid per day, if the supply drops out for just a few seconds (goes down to 90VAC for just a few seconds per day) then we get sheets of non cured ink going through the machine, which really is not wanted.
In that case you need to design your machine better - or 'hope' that it doesn't drop too often.

If you have specifications, then you need to design to them (or better still, exceed them a little).
 

tvtech

Well-Known Member
Most Helpful Member
I really feel for you Flyback. You have always been in over your head with all this stuff :(

You are in a situation I do not envy....you are trying VERY hard to salvage/rescue and try and lead @ the same time. You probably bawl you eyes out sometimes because you don't know what to do.....

I mean this in a good way. ETO Members will always try and help you. But we are not there with/alongside you at work. The Members here react on the info you give them....that is all they have to go on.

I am not exceptional in any way, but many here are. Think of the likes of Ron and others here that could sort your problems out chop chop if they were PHYSICALLY in your work environment...they would see the problems and warn you and maybe you would fly.

Speaking for myself only.....I am only good at seeing a fault. And it clicks in my mind. And then I fix it.
If someone tries to describe it to me to me, I am useless. Especially if they are not Technically inclined.

So, as a guy that loves Technical stuff and how and why things work and is a Member here and all that, I am actually useless for advise...

I will always share my little bit of knowledge I have with the stuff I have done. Even if not applicable to a specific thread. As long as people learn. And think. I am happy.

God speed Flyback. And of course...I love you all warts and all :)

Regards,
tvtech
 

ronsimpson

Well-Known Member
Most Helpful Member
thanks but our equipment runs 12 hours solid per day, if the supply drops out for just a few seconds (goes down to 90VAC for just a few seconds per day) then we get sheets of non cured ink going through the machine, which really is not wanted.
If things can go wrong then the will go wrong.
If things can go wrong in a big way then.................
A good engineer looks for the worst case and plans on that happening at some point.
 

jpanhalt

Well-Known Member
Most Helpful Member
JpanHalt:
thanks for your linked document, which says Japan mains is 100VAC +/-10v.....but our senior engineer tells us that Japan mains will virtually never be 10v down...he reckons its +/-5V and no more....who do we believe?
The last time you went against your boss, it didn't turn out so well, as I recall. What does the chief engineer want you to do? Have you discussed it with him/her? Is s/he open to spending the resources to buy or design a more robust power supply?

If not, it seems your decision should not be based on what you think is right, but rather on what you need to do at your current place of employment. Maybe your device can simply shut down and turn off the production line in a brown-out situation. Remember, even Superman can't save the world, if he is not there.

John
 

tvtech

Well-Known Member
Most Helpful Member
^^^ You know John, I don't know if anyone has said this yet: you are one of the good Guys on the Net.

I am not going to ramble on and just say what needs to be said...yes there are other Forums out there...many people need help.

Funny thing with me....I only remember good stuff...like my Brain is programmed that way. Flyback will never stop asking for help here. So you guys help.

I mean, I know you are an E Book developer over at AAC....but you always check in here.....you don't need to, but you do anyway. It's like you love ETO.

Like I do.

And then, I forgot what I was going to say next :wideyed:. Silly me.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
So, you put a UPS on it. If it's that important, put a motor generator on it.

You can't have 100% reliable power from a Utility. It doesn't happen anywhere.

In reality, you rent a power line disturbance monitor and then decide the most cost effective approach to fix it.

I had reliability issues once too and purchased a $1000 power conditioner for a system that pretty much ran 8 hrs a day.
One computer, 16 years, just mechanical problems and dust.

I got it because a computer we relied on before was becoming obsolete (non-PC), The same power conditioner had the same effect. Just dust, fans and 8" floppies. No other electronic failures.

It was not a UPS.

There were other machines that if they lost power for 5 minutes, it took a day to restart. We used a generator UNTIL we had to sacrifice that capacity for ventilation (safety). One safety PLC had to have a UPS, for basically 2 minutes until the generator kicked in. I got grief for the UPS I chose, because I knew that not all UPS's are generator friendly.

I wanted to instrument some other systems, but was turned down, The inconvenience and the number of interruptions in a year wasn't significant even though some of us were inconvenienced.

The fun one was we did an entire analyses of water we were just dumping down the drain and showed that a recirculation system would have been cost effective EXCEPT we didn't directly pay for water, We did cut the water use and used a small chiller for an x-ray tube. This water ran 24/7.

Analyze and pick your battles. Theorizing won't get you anywhere. You can ask the utility, right?

Unfortunately, the bean counters aren't pro-active by nature, but they will be instantly pro-active when some utility bozo, for instance, reverses the a phase to the building by accident. Again, we picked which machines that got 3 phase protection.

I wasn't very happy when I learned that about 5 systems had home-built systems that used the ground as a neutral for an add-on power fail helper. Ans: It's worked for 20 years without problems, It's against the NEC code, but ....

I also wanted to make the system more fault tolerant, but was over ruled. Resources were limited.
 
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