Phone charger plugged in 110v/400hz...
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Aircraft use 400hz, as the alternators can be smaller, (lighter) but the associated output is then subject to wide fluxuations in output.
Besides, if a charger is rated at 100-240V, why would a fluctuation matter to the output? I suppose the charger electronics could fail early with repeated fluctuations, but why would they carry over to the battery being charged?
@ underfire
I too am struggling to understand this, and I was trained in electronics.
Could you explain this a bit further? What are the 'fluxations' and the 'drops' you speak of?
it is the 400hz issue vs 60 hz. Aircraft use 400hz, as the alternators can be smaller, (lighter) but the associated output is then subject to wide fluxuations in output.
The power at 400hz, when the voltage fluxuates, the reactive drops through the system are even more significant, up to 7 times the difference. Typical chargers are not set up to handle this voltage swing, especially the drops.
The batteries are then subject to this flux, and it degrades them in respect to 60hz charging.
The power at 400hz, when the voltage fluxuates, the reactive drops through the system are even more significant, up to 7 times the difference. Typical chargers are not set up to handle this voltage swing, especially the drops.
The batteries are then subject to this flux, and it degrades them in respect to 60hz charging.
Could you explain this a bit further? What are the 'fluxations' and the 'drops' you speak of?
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The power at 400hz, when the voltage fluxuates, the reactive drops through the system are even more significant, up to 7 times the difference. Typical chargers are not set up to handle this voltage swing, especially the drops.
The batteries are then subject to this flux, and it degrades them in respect to 60hz charging.
A 400Hz 115 volt alternator is extremely stable, as they are mounted to systems that keep their rotation speed constant (it called a constant speed drive for that reason) If the voltage fluctuated, then there are a lot of electronic systems that would be damaged. ( alternator is controlled by a voltage regulator to keep it stable). Yes, output power can vary, that is due to changing requirements of the load.. IE the current supplied varies due to changing demand.
If the plug pack works at 400 Hz (I have never tried to do it) then its output will be the required 5/9/12/20 volts that it is designed to provide. If the power pack has a transformer in it, then its impedance will be very high at 400 Hz (about 6.5 to 8 times higher depending on its design frequency) then its ability supply current will be reduced.
The batteries are then subject to this flux, and it degrades them in respect to 60hz charging.
A 400Hz 115 volt alternator is extremely stable, as they are mounted to systems that keep their rotation speed constant (it called a constant speed drive for that reason) If the voltage fluctuated, then there are a lot of electronic systems that would be damaged. ( alternator is controlled by a voltage regulator to keep it stable). Yes, output power can vary, that is due to changing requirements of the load.. IE the current supplied varies due to changing demand.
If the plug pack works at 400 Hz (I have never tried to do it) then its output will be the required 5/9/12/20 volts that it is designed to provide. If the power pack has a transformer in it, then its impedance will be very high at 400 Hz (about 6.5 to 8 times higher depending on its design frequency) then its ability supply current will be reduced.
One of the reasons why 400Hz was originally used in aircraft is that you could use smaller and lighter inductive components (mostly transformers) which had the same performance as much larger/heavier ones designed for 50/60Hz.
The main problem with using these components outside their specifications is when the input frequency is lower, which reduces the impedance so allowing higher currents to flow which can overheat the device, e.g. using 400Hz equipment with 50/60Hz input = bad.
Modern SM power supplies are tolerant of input voltage/frequency within quite a wide band because of the way they work.
I would speculate that non-approved devices are disallowed from using power outlets on the flight deck not because they are expected to burst into flames but because of the possibility of a fault causing an fire in the supply wiring, which would be inaccessible in flight. Power sockets designed for in-flight use have much more in the way of protection built in, compared to the ground service ones. It may be as simple as that.
The main problem with using these components outside their specifications is when the input frequency is lower, which reduces the impedance so allowing higher currents to flow which can overheat the device, e.g. using 400Hz equipment with 50/60Hz input = bad.
Modern SM power supplies are tolerant of input voltage/frequency within quite a wide band because of the way they work.
I would speculate that non-approved devices are disallowed from using power outlets on the flight deck not because they are expected to burst into flames but because of the possibility of a fault causing an fire in the supply wiring, which would be inaccessible in flight. Power sockets designed for in-flight use have much more in the way of protection built in, compared to the ground service ones. It may be as simple as that.
Run an AC current through a rectifier, and you'll get DC with a very significant ripple. That could have an effect on the electronics downstream in a switching power supply.
In the abstract, a 400 HZ ripple should be easier to smooth out than a 50/60 HZ ripple (e.g. a smaller capacitor would be required). But it does seem possible that a system designed for 50/60 HZ and not tested at 400 would end up having problems at the higher frequency.
In the abstract, a 400 HZ ripple should be easier to smooth out than a 50/60 HZ ripple (e.g. a smaller capacitor would be required). But it does seem possible that a system designed for 50/60 HZ and not tested at 400 would end up having problems at the higher frequency.
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400 Hrz. Outlets
I concur with FullWings entirely. As the chief technical Captain for no less than three airlines I have repeatedly encountered this issue and discussed the matter with both Boeing and Airbus.
A very simplistic way to visualise the problem is this:-
If you laid out 400 paving slabs end to end to a garden shed at the bottom of your garden, you could walk effortlessly to your garden shed. Now consider laying out a pathway of 50 slabs alongside the 400. To take that path would require a great deal of energy as you jump from one slab to the other. 400 slabs in this case represents your 400Hrz. circuit and 50 slabs represent the 50 Hrz. circuit. Thus the energy supplied by the system to power your 50 Hrz. device is increased.
I have encountered on two occasions where the running of 50Hrz. units has caused the main ground power circuit breaker to run hot, but not enough for it to trip. However, the continual use in this condition lead to premature failure of the ground power circuit breaker. This is a NO GO item, Why? Because:-
On most big Aircraft the ground power circuit breaker supplies the Fire Detection and Extinguishing functions, loss of this circuit leaves you with no way of extinguishing a fire on the ground AND in flight.
Let this be known to all Cabin Services Departments who think they can just introduce DV players, telephone battery chargers an the like to the aircraft electrical system without a properly approved and certified modification. They CANNOT.
Some aircraft are modified to except 50Hrz equipment through special outlets, in particular to supply medical equipment. No doubt more modern aircraft will come with compliant power outlets. If you don't have such outlets you cannot use the 400Hrz supply unless you are using a certified appliance.
A very simplistic way to visualise the problem is this:-
If you laid out 400 paving slabs end to end to a garden shed at the bottom of your garden, you could walk effortlessly to your garden shed. Now consider laying out a pathway of 50 slabs alongside the 400. To take that path would require a great deal of energy as you jump from one slab to the other. 400 slabs in this case represents your 400Hrz. circuit and 50 slabs represent the 50 Hrz. circuit. Thus the energy supplied by the system to power your 50 Hrz. device is increased.
I have encountered on two occasions where the running of 50Hrz. units has caused the main ground power circuit breaker to run hot, but not enough for it to trip. However, the continual use in this condition lead to premature failure of the ground power circuit breaker. This is a NO GO item, Why? Because:-
On most big Aircraft the ground power circuit breaker supplies the Fire Detection and Extinguishing functions, loss of this circuit leaves you with no way of extinguishing a fire on the ground AND in flight.
Let this be known to all Cabin Services Departments who think they can just introduce DV players, telephone battery chargers an the like to the aircraft electrical system without a properly approved and certified modification. They CANNOT.
Some aircraft are modified to except 50Hrz equipment through special outlets, in particular to supply medical equipment. No doubt more modern aircraft will come with compliant power outlets. If you don't have such outlets you cannot use the 400Hrz supply unless you are using a certified appliance.
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Same here, both notebook computer and phone chargers work fine on 400 Hz. 
Or, so I'm told...
I'm not rightly sure that's how it works with a modern switching power supply. You are saying that a 400 Hz input to a power supply that works on 50Hz somehow delivers more energy? Your slab argument may work for cold fusion or frogs and lily pads but I don't think it is applicable in this case.
And you claim that a little 100 watt computer brick can somehow overload a ground power CB on an airliner?
A 757 has a 90 KVA ground power connection, right?
Or, so I'm told...
A very simplistic way to visualise the problem is this:-
If you laid out 400 paving slabs end to end to a garden shed at the bottom of your garden, you could walk effortlessly to your garden shed. Now consider laying out a pathway of 50 slabs alongside the 400. To take that path would require a great deal of energy as you jump from one slab to the other. 400 slabs in this case represents your 400Hrz. circuit and 50 slabs represent the 50 Hrz. circuit. Thus the energy supplied by the system to power your 50 Hrz. device is increased.
If you laid out 400 paving slabs end to end to a garden shed at the bottom of your garden, you could walk effortlessly to your garden shed. Now consider laying out a pathway of 50 slabs alongside the 400. To take that path would require a great deal of energy as you jump from one slab to the other. 400 slabs in this case represents your 400Hrz. circuit and 50 slabs represent the 50 Hrz. circuit. Thus the energy supplied by the system to power your 50 Hrz. device is increased.
And you claim that a little 100 watt computer brick can somehow overload a ground power CB on an airliner?
A 757 has a 90 KVA ground power connection, right?
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It is an interesting topic, having spent a little time looking at typical switch mode circuits it seems to me that the answer is, sadly, it depends. (warning, not a professional just a keen amateur wrt electronics)
If your power supply is a traditional linear power supply (Transformer->bridge rectifier->smoothing cap) it certainly will not work at 400hz.
If you have a switch mode power supply it appears initially to be simple as the AC is first rectified to DC then smoothed so what difference does input freq make? The higher the frequency input the smaller the input smoothing cap needs to be so it should work well at 400hz. Indeed looking at the smaller switch mode circuits I can see no reason they will not work well.
My only concern would be a switch mode power supply with passive power factor correction (PFC mandated on SMPS above 75 watts in the EU, this is more powerful laptop than ipad/phone territory). The point of the filter is to pass line frequency and block harmonics of the input frequency. 400Hz I think would be filtered by the PFC, I can't imagine it would do the inductor much good trying to run a SMPS with passive PFC on 400hz.
Does anyone here know more about PFC / AC harmonics/ power factor etc and can give professional opinion?
If your power supply is a traditional linear power supply (Transformer->bridge rectifier->smoothing cap) it certainly will not work at 400hz.
If you have a switch mode power supply it appears initially to be simple as the AC is first rectified to DC then smoothed so what difference does input freq make? The higher the frequency input the smaller the input smoothing cap needs to be so it should work well at 400hz. Indeed looking at the smaller switch mode circuits I can see no reason they will not work well.
My only concern would be a switch mode power supply with passive power factor correction (PFC mandated on SMPS above 75 watts in the EU, this is more powerful laptop than ipad/phone territory). The point of the filter is to pass line frequency and block harmonics of the input frequency. 400Hz I think would be filtered by the PFC, I can't imagine it would do the inductor much good trying to run a SMPS with passive PFC on 400hz.
Does anyone here know more about PFC / AC harmonics/ power factor etc and can give professional opinion?
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And, I believe some electronic flight kit tablets are currently FAA authorized to charge (but not operate) off 400 Hz cockpit outlets.
Even though I've seen various chargers and power supplies used successfully on 400 Hz power over the years, the folks that say it's not authorized certainly have a valid point. If anything happens and the feds take a closer look, your Personal Electronic Device plugged into an unauthorized power source will be under the microscope.
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Accident reports are riddled with pilots who believed SOP either did not apply to them or was beneath them.
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Same here, both notebook computer and phone chargers work fine on 400 Hz.
Or, so I'm told...
I'm not rightly sure that's how it works with a modern switching power supply. You are saying that a 400 Hz input to a power supply that works on 50Hz somehow delivers more energy? Your slab argument may work for cold fusion or frogs and lily pads but I don't think it is applicable in this case.
And you claim that a little 100 watt computer brick can somehow overload a ground power CB on an airliner? A 757 has a 90 KVA ground power connection, right?
Or, so I'm told...
I'm not rightly sure that's how it works with a modern switching power supply. You are saying that a 400 Hz input to a power supply that works on 50Hz somehow delivers more energy? Your slab argument may work for cold fusion or frogs and lily pads but I don't think it is applicable in this case.
And you claim that a little 100 watt computer brick can somehow overload a ground power CB on an airliner?
A 757 has a 90 KVA ground power connection, right?The 400Hz corresponds to the supply frequency, not the rated input frequency of the device.
It nicely illustrates how a higher input (supply) frequency reduces the needed size of input filter capacitor.
Old (heavy) linear supplies that have a stepdown transformer at the input will probably work at 400Hz, but depending on the core material might run a bit warmer due to increased hysteresis losses.
What will most definitely not work on 400 Hz if designed for 50/60 is anything that uses the frequency to control something, one example is a synchronous motor. For those 50/60 will make a difference, in some cases does not matte much, fan speed, in others a lot; record player or electric clock.
Interesting question pon power factor correction in larger supplies, although almost all are active not just magnetic filters.
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My company uses that gear. I've had some that work fine, but a fair percent can barely maintain a charge. I've actually had some lose power while "charging."
I believe some electronic flight kit tablets are currently FAA authorized to charge (but not operate) off 400 Hz cockpit outlets.
As noted by several posters, there are issues with the 115v chargers. Potential for EMI is there, as these chargers do not offer 2 way protection. While the aircraft 115v system has protections built in, it depends where, and what happens back to the protection.
The typical chargers were never meant to run on 400HZ. Switching supplies have PFC controllers and they don't work properly at 400 Hz. The controllers can cause considerable amounts of leakage current back into the equipment grounding conductor. this is where the 115v 400 Hz plug falls short.
The power plug referenced at the beginning is a DC plug and offers full protection including EMI. It is important to note that this is safe for all of these devices Apple, and non-Apple.
The iPad is not the only tablet of device in use on the flightdeck. Are phones permitted to be charged on the flightdeck? With that plug, other devices can be charged safely and without EMI. I dont have any vested interest in that plug, other than its use.
I really dont think the quality control on the out of the box charges is sufficient, even from a company like Apple.
Last edited by underfire; 25th Jun 2017 at 22:32.
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Aircraft power outlets
I didn't write the 'garden slab' analogy for the benefit of a university degree course in electrical engineering. It was written as a 'Visualisation' for the benefit of airline cabin crew. Those that wish to deride the idea should work on a better way of explaining the matter to those who have no electrical or mechanical expertise. That would be more constructive, so take it in the manner for which it was intended.
The 'Ground service' circuit breakers that were burnt out, were because the airline concerned decided that they would supply DVD players to the passengers and the players were charged by the ground service receptacles on board. This decision was made without any consultation with maintenance nor myself at the time. I discovered what they were doing on a flight to the USA. The later failure of the ground service CBs were attributed to the charging of those units on board by Boeing. If you need to argue the point please contact them, but I can tell you now what they will say. You cannot plug anything into the aircraft that is not approved. You're effectively modifying the aircraft's electrical system and for that you require a minor or major modification, which in this case would include an electrical power and supply assessment. Sadly, there is always someone on Pprune who wants to argue even when the argument has been concluded, so those who wish to connect to the aircraft will need to show the modification approval obtained to do that or a notification from Boeing, Airbus or whoever made your aircraft in the form of a letter stating “NO TECHNICAL OBJECTION”, until then you CANNOT connect to the aircraft power outlet.
The 'Ground service' circuit breakers that were burnt out, were because the airline concerned decided that they would supply DVD players to the passengers and the players were charged by the ground service receptacles on board. This decision was made without any consultation with maintenance nor myself at the time. I discovered what they were doing on a flight to the USA. The later failure of the ground service CBs were attributed to the charging of those units on board by Boeing. If you need to argue the point please contact them, but I can tell you now what they will say. You cannot plug anything into the aircraft that is not approved. You're effectively modifying the aircraft's electrical system and for that you require a minor or major modification, which in this case would include an electrical power and supply assessment. Sadly, there is always someone on Pprune who wants to argue even when the argument has been concluded, so those who wish to connect to the aircraft will need to show the modification approval obtained to do that or a notification from Boeing, Airbus or whoever made your aircraft in the form of a letter stating “NO TECHNICAL OBJECTION”, until then you CANNOT connect to the aircraft power outlet.
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The point is that 50hz chargers might work ok, but they might not. You simply have no idea of the internal design . Some could well overheat, or cause trips.
Simply beacuse some people have found it works does not make it right or safe.
It strikes me that deviance from standards like this is a worrying trait in a pilot.
(Degree qualified electronics engineer with 25 years experience)
Simply beacuse some people have found it works does not make it right or safe.
It strikes me that deviance from standards like this is a worrying trait in a pilot.
(Degree qualified electronics engineer with 25 years experience)
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On-Mark, hoss, others.
Thank you for details and experience. This is not simply approved for use, but the conditions and nuances.
As noted, depending on the ac and use, the chargers do not work that well, and there have been studies, where the chargers do not charge very well and do reduce battery life. As with many things, lab studies and ac certs do not translate to reality, but in real use, with the longer term studies, the issues have come to light.
One should also note the very specifics of the approval. I noted before, there are approvals for use on the flight deck, but dont stop there. That is not blanket approval for charging on the flight deck, nor charging while in use. Several airline cert do say approved for use, but are not approved for charging while in use, nor approved for charging on the flightdeck.
The use of these electronic devices is fairly new, and now that longer term information is available, one can see how the rules and regs are developing accordingly.
Thank you for details and experience. This is not simply approved for use, but the conditions and nuances.
As noted, depending on the ac and use, the chargers do not work that well, and there have been studies, where the chargers do not charge very well and do reduce battery life. As with many things, lab studies and ac certs do not translate to reality, but in real use, with the longer term studies, the issues have come to light.
One should also note the very specifics of the approval. I noted before, there are approvals for use on the flight deck, but dont stop there. That is not blanket approval for charging on the flight deck, nor charging while in use. Several airline cert do say approved for use, but are not approved for charging while in use, nor approved for charging on the flightdeck.
The use of these electronic devices is fairly new, and now that longer term information is available, one can see how the rules and regs are developing accordingly.
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A lot of points on this thread are very valid.
However, in response to the OP's question, Apple 5W, 10W and 12W iPhone and iPad chargers with A-type US connectors are certified for 115V/400Hz. There is a pretty good reason for that.
https://support.apple.com/en-us/HT202916 - this reference on Apple's site is dated 21 June 2017 but it has been around a lot longer than that.
However, before you go and plug one in, you would also need to comply with whatever EFB approvals are in place by your operator to be approved to use that power outlet for your EFB.
However, in response to the OP's question, Apple 5W, 10W and 12W iPhone and iPad chargers with A-type US connectors are certified for 115V/400Hz. There is a pretty good reason for that.
https://support.apple.com/en-us/HT202916 - this reference on Apple's site is dated 21 June 2017 but it has been around a lot longer than that.
However, before you go and plug one in, you would also need to comply with whatever EFB approvals are in place by your operator to be approved to use that power outlet for your EFB.
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Here's the text from the Apple web page cited above:
Elsewhere Apple states that the iPad chargers can be used to charge an iPhone:
https://support.apple.com/en-us/HT202105
But as everybody points out, it will probably work fine but might still be illegal unless you get a stack of approvals from the feds, the airline, the unions, the manufacturer etc.
And the original question was about using an iPhone, not iPad, power adapter on 400 Hz. I've seen it done with no problem in years past. But, it is probably not legal and not covered under Apple's warranty if the phone, adapter or cable bursts into flames.
iPad USB power adapter certifications
Every iPad comes with an Apple USB power adapter that is certified to meet government safety standards in countries where iPad is available.
Many of these countries, including the United States, have adopted the Safety of Information Technology Equipment standard, IEC/UL 60950-1. Learn about the certifications for iPad USB power adapters.
Depending on the model, iPad comes with a 5W, 10W, or 12W power adapter. All three Apple USB power adapters are designed for use with power sources rated to provide 100V AC to 240V AC at 50Hz to 60Hz. Find more information about iPad USB power adapter compatibility.
The Type A (flat parallel-blade design) Apple 5W as well as the 10W and 12W USB power adapters (with Type A AC plug attached) also comply with the IEC/UL 60950-1 standard for use with power sources rated to provide 115V AC at 400Hz.
Published Date: Jun 21, 2017
Every iPad comes with an Apple USB power adapter that is certified to meet government safety standards in countries where iPad is available.
Many of these countries, including the United States, have adopted the Safety of Information Technology Equipment standard, IEC/UL 60950-1. Learn about the certifications for iPad USB power adapters.
Depending on the model, iPad comes with a 5W, 10W, or 12W power adapter. All three Apple USB power adapters are designed for use with power sources rated to provide 100V AC to 240V AC at 50Hz to 60Hz. Find more information about iPad USB power adapter compatibility.
The Type A (flat parallel-blade design) Apple 5W as well as the 10W and 12W USB power adapters (with Type A AC plug attached) also comply with the IEC/UL 60950-1 standard for use with power sources rated to provide 115V AC at 400Hz.
Published Date: Jun 21, 2017
Using iPad power adapters with your iPhone, iPad, and iPod
Apple USB power adapters for iPad can also be used to charge iPhone, iPod, Apple Watch, AirPods, and other Apple products.
You can use Apple 12W and 10W USB power adapters to charge your iPad, iPhone, iPod, Apple Watch, and other Apple accessories, like AirPods and Siri Remote. Just connect your device to the power adapter with the Lightning to USB Cable, 30-pin to USB cable, or Apple Watch charger that came with your device.
Apple USB power adapters for iPad can also be used to charge iPhone, iPod, Apple Watch, AirPods, and other Apple products.
You can use Apple 12W and 10W USB power adapters to charge your iPad, iPhone, iPod, Apple Watch, and other Apple accessories, like AirPods and Siri Remote. Just connect your device to the power adapter with the Lightning to USB Cable, 30-pin to USB cable, or Apple Watch charger that came with your device.
But as everybody points out, it will probably work fine but might still be illegal unless you get a stack of approvals from the feds, the airline, the unions, the manufacturer etc.
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Let me add a little something to OMB's discourse. When aircraft adopted the 400 Hz standard, there was no such thing as a switch mode power supply.
As well as the filter caps the weight of iron in the transformers of all the avionics could be substantially reduced.
After an excellent landing etc...
As well as the filter caps the weight of iron in the transformers of all the avionics could be substantially reduced.
After an excellent landing etc...