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I hope this is the right place to ask this: I am relocating from the US (110V 60Hz) to Germany (240V 50Hz) and want to bring some of my electronic devices. It seems worth the hassle in my case (not the question here) and I already own two step up/down converters, one 1000W and the other 3000W. I am confident that I can power my plasma TV (can do both PAL/NTSC, etc.) and HiFi AVR through the 3000W transformer and a small guitar amp (20W full tube) through the 1000W transformer until they die. I am curious though if there are potential problems with some of the devices that I am consider bringing as well, e.g. due to 50Hz instead of 60Hz, especially some the ones that contain motors:

  • Set of LED string lights using 2 watt LED standard base bulbs: Brightech Ambience Pro - White, Waterproof LED Outdoor String Light
  • String light remote control: SUNYE Max Power 200W Waterproof Outdoor String Lights Wireless Remote Control
  • Paper shredder: Omnitech 10-Sheet Cross-Cut Shredder (OT-NXC102PA))
  • Heat gun: Seekone 1800W (includes a fan of course, basically a hair dryer)
  • Hot glue gun for crafting/hobby
  • Air mattress with integrated fan/pump: Serta Never Flat
  • Utility fan: Lasko 4900 Pro-Performance High Velocity Utility Fan (~160W)

I am aware of the power constraints and I only want to know if this would work in principle or if bringing some of this is completely pointless (or will wear down some parts very quickly). I'd prefer to keep using as many of these items as possible, if they have a chance of working.

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    \$\begingroup\$ Most devices have a label stating what voltages and frequencies they work on. \$\endgroup\$ – StarCat May 3 at 6:18
  • \$\begingroup\$ And manuals. This is basically how to use my electronics devices question. \$\endgroup\$ – Justme May 3 at 7:53
  • \$\begingroup\$ No kidding! I am aware of the labels on those devices and know that I need to convert voltages and understand that there are starting loads and power limits of the converters, including needed headroom, etc, thanks. I was more curious about effects of the frequency change. AFAIK, motors,etc. handle this differently. Have a look at the answer I accepted, maybe there is something new for you as well! \$\endgroup\$ – tomka May 3 at 13:28
  • \$\begingroup\$ PAL? In the UK, the last PAL transmitter was switched off in 2012; I imagine Germany was probably even ahead of us. Yup : June 2009. Now DVB-T and DVB-T2. \$\endgroup\$ – Brian Drummond May 3 at 14:43
  • \$\begingroup\$ Ah great, thanks! Even better then, the TV supports that, too. \$\endgroup\$ – tomka May 3 at 16:09
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Heating elements shouldn't care, but the motors will run slower and have less torque, but still run hotter than they otherwise would for with this decreased power output.

Particularly vulnerable are things that have a high starting load like your paper shredder. Fans have decreased torque when running slower so that helps reduce the heating...unless they use their own airflow for cooling. The air mattress pump could struggle as the air mattress fills up and puts more torque on the motor.

Your heatgun gets a double whammy issue since the heater will run with the same amount of power but the fan will run slower so your heatgun will be hotter than it should and the motor will also be hotter.

ADDENUM:

Imagine an air tank constantly filled up and emptied of air. For the same mass of air being moved, you can fill and then empty the the air in smaller amounts at higher frequency, or larger amounts of water at lower frequency. But what happens if you try and move the same amount of air on a tank that is too small for the fill/empty frequency? You have to overfill it which makes the pressure inside higher than it should be and the tank is stressed, begins to burst, or leaks.

The air is the same as magnetic flux and the filling and emptying being the alternating of current. A mass of magnetic steel can only hold so much magnetic flux before it starts to "leak" which makes it inefficient and produce heat. Magnetic steel is used to make both transformers and motors.

A 60Hz transformer is smaller than a 50Hz transformer of the same power because it is designed to move smaller amounts of flux back and forth at higher frequencies so doesn't need to contain as much flux in it at any one instant to handle the same amount of power.

Similarly, two motors that provide the same power: The one that provides more of that power in speed than torque is smaller because it doesn't need to apply so much torque since that torque is spread out over more revolutions, whereas the one that is slower is larger because it has turns more slowly so more torque must be concentrated in the each revolution to produce the same amount of power. The larger motor is both mechanically beefier because it has to withstand the larger torque, but it also needs to contain more magnetic steel in the first place so can efficiently contain more flux at any instant in time which is used to produce that torque.

Trying to run either motor or transformer at a lower frequency that what is intended but trying to draw the same amount of power from it as before makes the magnetic steel "burst at the seams" so to speak. That's why your laptop and computer power supplies run at kHz or MHz. So they can use a tiny transformer and inductors for the same power.

So back to your original question, it is not that the 60Hz runs cooler than one built for 50Hz. They both run at more or less the same temperature as each other because that's how they are designed. But the one built for 50Hz has more steel in it to account for the higher flux concentrations present. The 60Hz is built with less steel because it doesn't need as much steel. So I would expect a 50Hz transformer to run cooler than it normally would at 60Hz (though being oversized introduces other types of losses, as well as cost).

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  • \$\begingroup\$ Thanks! That's exactly the sort of information I was looking for! \$\endgroup\$ – tomka May 3 at 13:22
  • \$\begingroup\$ Also, flux in transformer core is inversely proportional to frequency. So transformers will operate closer to design saturation limit. May get distorted output. \$\endgroup\$ – relayman357 May 3 at 13:37
  • \$\begingroup\$ Thanks, that's interesting and good to know! I haven't heard of that problem before. Without knowing the electrical context here and on a rather high level, does this mean that transformers built for 60Hz environments run cooler than one built for 50Hz? Does this practically often make a difference in design (e.g. slightly smaller cable length, less cooling)? \$\endgroup\$ – tomka May 3 at 14:03
  • \$\begingroup\$ @tomka See addenum \$\endgroup\$ – DKNguyen May 3 at 18:26
  • \$\begingroup\$ Thank you very much for taking the time to write down this analogy! It makes the problem very clear. \$\endgroup\$ – tomka May 5 at 2:09
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I am curious though if there are potential problems with some of the devices that I am consider bringing as well, e.g. due to 50Hz instead of 60Hz, especially some the ones that contain motors:

Devices which have mains frequency transformers or induction motors may have problems, also those that use the mains frequency for timing such as electric clocks and turntables.

When a 60 Hz transformer is used at 50 Hz the magnetizing current is higher and it runs closer to saturation, which makes it run hotter. This can sometimes be mitigated by using a lower voltage (eg. 100 VAC instead of 120 VAC). A similar effect occurs with induction motors, which also may run significantly slower depending on load.

However most modern electronic devices use switching power supplies, and some appliances use 'universal' motors (which run on AC or DC) or DC motors fed through a rectifier. Paper shredders, high flow rate air pumps and heat guns often have a universal or DC motor. You may be able to tell which type of motor is used by the sound - universal/DC motors usually have a high pitched whine, while induction motors just make a low humming sound.

The only item on your list that I would be concerned about is the Lasko 4900, which probably has an induction motor.

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  • \$\begingroup\$ Thank you, that's also very helpful to know! Is the higher magnetizing current the same as magnetic flux and are universal motors just generally better equipped to handle higher magnetizing currents than induction motors or is it no issue at all there? \$\endgroup\$ – tomka May 5 at 2:22

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