Convert US standard 115V to International 230V

[IanB]

Radiolistener, can you delete your posts?

You have not read the thread, and you are just adding a whole bunch of useless noise on the end of a solved problem.

[radiolistener]

Note that the op’s application involves equipment rated for operation at either 50 or 60 Hz, and the frequency conversion is not required.

In order to support both 50 Hz and 60 Hz standards, the device needs to be rated to work at least within frequency range from 48.5 Hz to 61.8 Hz. This is because it needs to support allowed mains frequency variation ±3%.

If it really supports all frequency range which include both standard, then he can use 1:2 voltage transformer. But it requires that device needs to be carefully checked and tested in order to comply with both frequency standards.

[shapirus]

In order to support both 50 Hz and 60 Hz standards, the device needs to be rated to work at least within frequency range from 48.5 Hz to 61.8 Hz. This is because it needs to support allowed mains frequency variation ±3%.

If it really supports all frequency range which include both standard, then he can use 1:2 voltage transformer. But it requires that device needs to be carefully checked and tested in order to comply with both frequency standards.

Once again, did you read the thread? It was figured out already that the device is using switching power supplies which support both AC voltage and frequency variants on the input.

[Zero999]

Radiolistener, can you delete your posts?

Unfortunately, that would mean him admitting he's mistaken and going by his posting history, is something he appears to be unable to do.

[radiolistener]

Once again, did you read the thread? It was figured out already that the device is using switching power supplies which support both AC voltage and frequency variants on the input.

yes, I read, the topic starter mentioned that his equipment consume 20 A from 115V mains, this is about 2300 Watt power.

He also mentioned example of 2 PSU which is used in his system: Meanwell HRP-150-24 and HRP-600-36. This is 150W and 600W SMPS power supplies which already have universal AC input with 47 - 63 Hz frequency range.

These PSU can be used directly. But this is just 750W power consumption.

But what about power supply for the rest 1550 Watt power consumption?
Are you sure that they also compatible with both frequency standard?


There is also another possible issue which is critical for medical devices, even if he using PSU which all are compatible with all mains standards, it still needs to be tested with both mains frequency. Note that the mains frequency has leakage through PSU in a form of a ripple and/or interferences and can affect equipment functions, especially if this is device which uses sensitive measurements.

For example precise ADC can have configurable rejection filter which can be software configured for 50 or 60 Hz depends on user environment. And it needs to be taken into account very carefully especially for medical devices (which is the case for topic starter question). And this example is not abstract this is example of a real case for medical devices.

[shapirus]

Yes that's good point. It's not clear if those PSUs are the only PSUs the device uses, given the strange difference in the power levels mentioned initially.

[IanB]

According to the OP, the two power supplies are the only mains loads. The reason for the 20 A requirement was unclear, due to an earlier designer who has now left the project. It may simply have been a very conservative design.

These PSU can be used directly. But this is just 750W power consumption.

It is 750 W output power. Allowing for power supply efficiency the input power is closer to 900 W. But once again, this was covered earlier in the thread.

There is also another possible issue which is critical for medical devices, even if he using PSU which all are compatible with all mains standards, it still needs to be tested with both mains frequency. Note that the mains frequency has leakage through PSU in a form of a ripple and/or interferences and can affect equipment functions, especially if this is device which uses sensitive measurements.

For example precise ADC can have configurable rejection filter which can be software configured for 50 or 60 Hz depends on user environment. And it needs to be taken into account very carefully especially for medical devices (which is the case for topic starter question). And this example is not abstract this is example of a real case for medical devices.

There is a mains input filter in the design. Described earlier in the thread.

[radiolistener]

There is a mains input filter in the design. Described earlier in the thread.

Mains filter cannot help. In case that I mentioned it was interference induced on sensors due to near field coupling with mains wires around room. It was not related to PSU.

This is why I said that the device should be carefully tested if it's planned to use it within environment with mains frequency which is different than one which is used during device design, debugging and testing.

Even if PSU can work with all mains standards, it cannot guarantee that the device will works ok with it. It was designed and tested for 60 Hz environment and you cannot predict it's behavior with 50 Hz environment because no one tested it.

[shapirus]

Then again, frequency will be the same: it's 60 Hz in both cases.

[Terry Bites]

No!
Adding an external transformer voids the 60601 compliance.
Modding any MD will require retest to 60601 using approved test devices and methods.
You have been warned!

[am1]

Hi all, yes, those are the only PSU used in the device. However, there are several breakers used as well (listed). All are rated for more than the needed 220-240V, but would I need to replace them with double pole line-neutral breakers? System uses the following:


Circuit Breaker 2P 20A 240VAC/60DC Blk Rckr      SCHURTER   Allied Electronics   4430.2196
Circuit Breaker 1-P 4A 480Y/277VAC      ABB   SU201M-C4
Circuit Breaker 1-P 2A 480Y/277VAC      ABB   SU201M-C2
Circuit Breaker 1-P 16A 480Y/277VAC      ABB   SU201M-C16
Circuit Breaker 1-P 3A 480Y/277VAC      ABB   SU201M-K3
Circuit Breaker 1-P 15A 480Y/277VAC      ABB   SU201M-K15
Circuit Breaker 1-P 10A 480Y/277VAC      ABB   SU201M-K10[/li]

Adding an external transformer voids the 60601 compliance.

If the equipment selected is already ME certified through IEC, I believe there are sometimes only documentation updates required by them.. but I could be wrong. I believe we bypassed additional testing when a power cord change was made because it was an already CE/UL certified part. Even if this is true, though, I have not been able to find any ready to use 3000W step down transformers in my research so far. We may ask the customer to self-provide the SDT themselves, but I would like to have options available on our end as well.

[IanB]

You might want to plug the device into a Kill-A-Watt and measure the power consumption under full load. I suspect it won't be more than 1000 W, but this way you can measure it and find out.

[radiolistener]

You might want to plug the device into a Kill-A-Watt and measure the power consumption under full load. I suspect it won't be more than 1000 W, but this way you can measure it and find out.

I'm afraid that such approach is not acceptable for safety critical devices development because it don't guarantee that device will never consume more power under some specific conditions.

[IanB]

I'm afraid that such approach is not acceptable for safety critical devices development because it don't guarantee that device will never consume more power under some specific conditions.

But if you can't identify and test what those specific conditions are, then the device could never be certified?

Also, it has not been specified that a robotic gait trainer is a safety-critical device. If it stops working for any reason, it is hard to see what harm would come to the person using it.

[radiolistener]

But if you can't identify and test what those specific conditions are, then the device could never be certified?

Also, it has not been specified that a robotic gait trainer is a safety-critical device. If it stops working for any reason, it is hard to see what harm would come to the person using it.

Undefined/unspecified behavior of device is not acceptable because it is unpredictable and can make harm to the patient. This is uncontrolled potentially life threatening risks for the patient and it's presence shows serious issue in validation/verification process and broken quality management system. 

[IanB]

I'm afraid that such approach is not acceptable for safety critical devices development because it don't guarantee that device will never consume more power under some specific conditions.

Undefined/unspecified behavior of device is not acceptable because it is unpredictable and can make harm to the patient. This is uncontrolled potentially life threatening risks for the patient and it's presence shows serious issue in validation/verification process and broken quality management system. 

The above two statements are in contradiction with each other. Either you can specify the designed behavior, or you cannot. If you specify the behavior, then you cannot also say, "but this is unacceptable, because it may behave in ways other than those specified".

[radiolistener]

The above two statements are in contradiction with each other. Either you can specify the designed behavior, or you cannot. If you specify the behavior, then you cannot also say, "but this is unacceptable, because it may behave in ways other than those specified".

I don't see contradiction. If you're designed device properly, then your device already has defined/specified valid range for the power consumption, which can be used for device testing. But if power consumption is unknown and you're using DMM to discover it, then power consumption of your device is undefined/unspecified.

[tooki]

In order to support both 50 Hz and 60 Hz standards, the device needs to be rated to work at least within frequency range from 48.5 Hz to 61.8 Hz. This is because it needs to support allowed mains frequency variation ±3%.
…

Once again, did you read the thread? It was figured out already that the device is using switching power supplies which support both AC voltage and frequency variants on the input.

Radiolistener, can you delete your posts?

Unfortunately, that would mean him admitting he's mistaken and going by his posting history, is something he appears to be unable to do.

I find it quite remarkable how someone whose username is “radiolistener” can be so very bad at listening!

[Zero999]

In order to support both 50 Hz and 60 Hz standards, the device needs to be rated to work at least within frequency range from 48.5 Hz to 61.8 Hz. This is because it needs to support allowed mains frequency variation ±3%.
…

Once again, did you read the thread? It was figured out already that the device is using switching power supplies which support both AC voltage and frequency variants on the input.

Radiolistener, can you delete your posts?

Unfortunately, that would mean him admitting he's mistaken and going by his posting history, is something he appears to be unable to do.

I find it quite remarkable how someone whose username is “radiolistener” can be so very bad at listening!

My favourite one was when it took several pages to explain why a capacitor connected to a generator doesn't increase the power consumption, ignoring the tiny extra I²R losses.

[tooki]

My favourite one was when it took several pages to explain why a capacitor connected to a generator doesn't increase the power consumption, ignoring the tiny extra I²R losses.

I missed that thread at the time. And it was before I learned anything about AC theory anyway, so it would have been lost on me then. But I read it now and the obstinance made some of my brain cells commit seppuku. I find it hilarious that the thread contains a literal crayon drawing that explains it clearly, but still it continued for pages and pages…

[radiolistener]

My favourite one was when it took several pages to explain why a capacitor connected to a generator doesn't increase the power consumption, ignoring the tiny extra I²R losses.

For what reason you're writing it in that way like I was claimed that capacitor will consume the power? This is false. I didn't claimed that.

We're talked how the power returned from capacitor to generator affects its mechanical rotation. And looking at that discussion now, it appears that I missed to clarify that I was talked about instantaneous power and my opponents are talked about average power and it leads to confusion.

To be clear, if you connect capacitor it will lead to higher instantaneous power consumption during one part of cycle and less instantaneous power consumption during another part of cycle. Average power consumption during full cycle will be the same (if we exclude higher power loss on wires).

My opponents claimed that adding capacitor don't affects power applied to generator rotor, just because they talked about average power which is really will be the same, but I didn't agreed with them because I was talked about instantaneous power which will be increased. 

Regarding to the power consumption, it is obvious that it will increase power consumption due to heat losses in the wires, because energy will flows back and forth between the generator and capacitor and of course it will increase power losses in wires in comparison with pure active load where power loss happens only once when power is transferred in single direction from generator to the load.

[tooki]

My favourite one was when it took several pages to explain why a capacitor connected to a generator doesn't increase the power consumption, ignoring the tiny extra I²R losses.

For what reason you're writing it in that way like I was claimed that capacitor will consume the power? This is false. I didn't claimed that.

No, the wording doesn’t say the power consumption is in the capacitor, just that you thought adding the capacitor increased power consumption in total. Which is something you stated in the thread over and over and over.

We could substitute “reading comprehension” for listening, and you just proved our point: you don’t listen, or in this case, read carefully. You’re seeing what you want to see, not what’s actually written.

[radiolistener]

No, the wording doesn’t say the power consumption is in the capacitor

Yes, I see, but you wrote it in that way that it looks like I was said that capacitor will consume power. But that's not true.

just that you thought adding the capacitor increased power consumption in total

No. I don't have that thought.

Which is something you stated in the thread over and over and over.

I didn't stated that. I was talk about different thing.

You're needs to apply additional power to charge capacitor, this is why instantaneous power will be higher. That additional power will not be loss, it remains in the system, but it is required to be taken from generator. Which requires to apply more power on generator rotor.


After all, I don't understand - what is the reason to link that discussion in this topic? Could you please clarify?
I think it will be more correct to discuss it in original topic. Isn't it?

We could substitute “reading comprehension” for listening, and you just proved our point: you don’t listen, or in this case, read carefully. You’re seeing what you want to see, not what’s actually written.

You're just pull an owl on a globe. It looks like you're see what you want to see, not what actually is.

Really, I don't see the reason for your aggression. You are acting like a bully, trying to find a reason to quarrel. For what?

Сould you please calm down and communicate on the topic instead of expressing your subjective opinion about persons?   

[Jwillis]

Just to clarify, North American standard household voltage to both 120V and 240V @ 60Hz. Being split phase.

[soldar]

This thread makes me want to bang my head against the wall. Besides all the noise and useless arguing, there is something that bothers me and it is that I believe the OP is just not qualified or certified and should not be making this type of decisions. It is one thing to ask in a forum for personal things or for professional things if one has the appropriate knowledge and background, but this, to me, screams like a bad idea.

There are too many unknown variables and the OP is, clearly, not qualified. A medical device sold professionally and for export and this is how it is being designed?  In America? Really? Nobody thinks there is something wrong in this scenario? Really?

My response would be that you need to hire a qualified engineer who does not need to ask this type of questions and who is responsible for their work.

Some months ago a friend asked me if I could repair an automatic watering system box device which had not lasted long. Proudly designed and made in the USA ... and complete crap. The power supply part was designed by someone totally unqualified for the job.  Among other things it had a resistor making lots of heat right next to components which could not take the heat and all enclosed in a weather-proof box with no ventilation. It was crap and there was really no good repair except to replace the unit with something else. ... probably designed and made in China with better design and quality.

I am all for helping people learn and develop their own projects but for commercial, professional products you need a pro.

Just the way I see it.