60 Hz vs. 400 Hz.
- Thread starter ualwoody
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It would depend on the Laptop Power Supply technology being used. If it is Switch Mode Power Supply it may work because a SMPW converts the AC line directly to DC. The problem could/would be the AC line filters installed from L-G, L-N, and N-G would be designed for 60 Hz and could burn up at the higher frequencies.
If it is a linear power supply (using a step-down transformer) it would not likely work at all, or the output voltage would be way to low.
If it is a linear power supply (using a step-down transformer) it would not likely work at all, or the output voltage would be way to low.
400Hz
400Hz
As a flight attendant, I've charged my cell phone and laptop many a time using the onboard 400Hz power outlet. In flight I've never had a problem, but once in a great while I'd get a power surge when they switch from ground power to the APU or vice versa, most notibly on the B767, although I word of mouth says the 737 isn't immune to these either. Get a small surge protector to protect your investment.
400Hz
As a flight attendant, I've charged my cell phone and laptop many a time using the onboard 400Hz power outlet. In flight I've never had a problem, but once in a great while I'd get a power surge when they switch from ground power to the APU or vice versa, most notibly on the B767, although I word of mouth says the 737 isn't immune to these either. Get a small surge protector to protect your investment.
jrannis
Senior Member
- Location
- Fort Lauderdale/ Miami
Transformers are smaller if I remember correctly. Im sure thats not the only reason.
JayWes38
New member
- Location
- Pennsylvania
Transformer size and weight is the answer.
Transformer size and weight is the answer.
Why do airplanes run on 400 hz.
Simple, it is a matter of weight. Transformers are affected by frequency, and if you design transformers for a living, you know that the higher the frequency the less iron you need due to the basic physics (the EMF generated in a coil is proportional to both to flux and frequency- hence higher frequencies require less flux and laes iron.) 400 Hz transformers, and lamp ballasts, generators motors are all lighter and smaller then comparable 60 Hz units.
Also turbines engines run faster then 3600 RPM of a two pole 60 Hz generator, and the gearing and constant-speed-drive unit used in earlier jet aircraft is simplier and lighter. is simplier. [Most newer aircraft use wild frequency generators aand convert the resulting current to a fixed 400 Hertz.
Note this principle applies for 50 and 60. Since the europeon systems use 380 volts instand of 480, motors can be dual-rated. sincre the current is the same, the horsepower, and speed at 50 hz is 5/6 of the 60 Hz rating.
Transformer size and weight is the answer.
Why do airplanes run on 400 hz.
Simple, it is a matter of weight. Transformers are affected by frequency, and if you design transformers for a living, you know that the higher the frequency the less iron you need due to the basic physics (the EMF generated in a coil is proportional to both to flux and frequency- hence higher frequencies require less flux and laes iron.) 400 Hz transformers, and lamp ballasts, generators motors are all lighter and smaller then comparable 60 Hz units.
Also turbines engines run faster then 3600 RPM of a two pole 60 Hz generator, and the gearing and constant-speed-drive unit used in earlier jet aircraft is simplier and lighter. is simplier. [Most newer aircraft use wild frequency generators aand convert the resulting current to a fixed 400 Hertz.
Note this principle applies for 50 and 60. Since the europeon systems use 380 volts instand of 480, motors can be dual-rated. sincre the current is the same, the horsepower, and speed at 50 hz is 5/6 of the 60 Hz rating.
here's your sign!
here's your sign!
the mystery of 400 hz explained... http://www.aerospaceweb.org/question/electronics/q0219.shtml
weight reduction
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here's your sign!
the mystery of 400 hz explained... http://www.aerospaceweb.org/question/electronics/q0219.shtml
weight reduction
$$$$$
e57
Senior Member
- Location
- San Francisco, CA
Doubt any receptical (like a 5-15) on an airplane that you can "PLUG" a consumer electronic device into would be 400hz.... But regenerated at 50-60 using an on-board rotary or electronic frequncy convertor.
http://www.avionicinstruments.com/p_converters_specs.html
Anyway - my understanding was that many radar systems are ineffeciant at lower freq's and needed much higher power internal to the equipment than available from DC or lower freq AC - could be wrong???
http://www.avionicinstruments.com/p_converters_specs.html
Anyway - my understanding was that many radar systems are ineffeciant at lower freq's and needed much higher power internal to the equipment than available from DC or lower freq AC - could be wrong???
I frequently work with this stuff (in addition to ground and mobile power systems) and the biggest two problems are emi filter leakage current and power factor issues. Many switching supplies have PFC controllers and they don't work properly at 400 Hz. The emi filters cause considerable amounts of leakage current into the equipment grounding conductor. This is a safety issue and on military aircraft can violate their codes. They won't let you have too much weight and everything must be very small, so it is very challenging giving them what they need. Yes, there are converters (usually UPS) to 60 Hz on some aircraft, specifically those that have a lot of "customer" electronics on board. They also use them because they eliminate the power interruptions when switching from bus to bus or from ground supply. I once worked on one power distribution control system that handled 28 vdc, 400 Hz three phase, and 60 Hz single phase from a large UPS. By the way, on military aircraft if you draw more than 500 watts you must use 3-phase. The 60 Hz UPS takes three phase in and you can thus get around that requirement. The use of 28V is getting less common for heavier loads anymore.
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