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Voltage
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Voltage

I have this item from U.S.: FoodSaver V2244 Advanced Design Vacuum Sealer. The information for voltage is "120V, 60Hz, 110watt"

Here in Philippines, our standard voltage is 220V. I found some transformer with the specs of: "150 VA, input 240 volts, output 120 volts, 60 Hz". But I'm still afraid to use this item.

Any can help me if this item(transformer) is compatible or safe to use on the said imported product?

Thanks.

Comments

  • linuxthefishlinuxthefish Member
    edited July 2016

    EDIT: wrong numbers, see @elgs's post

    Yes, it's fine. 150 volt amps at 120 volts is 1.25 amps, or around 150 watts depending on the power factor.

    I wouldn't use it for too long though, you are running close to the limit of your transformer. If something does go wrong it shouldn't damage your appliance.

    Thanked by 1juhan
  • juhanjuhan Member

    @linuxthefish said:
    Yes, it's fine. 150 volt amps at 150 volts is 1 amp, or around 150 watts depending on the power factor.

    Do you mean the maximum wattage of transformer is 150watt, then my item is only 110watt? It doesn't matter, right?

  • @juhan said:

    @linuxthefish said:
    Yes, it's fine. 150 volt amps at 150 volts is 1 amp, or around 150 watts depending on the power factor.

    Do you mean the maximum wattage of transformer is 150watt, then my item is only 110watt? It doesn't matter, right?

    Correct, your item draws less current than the maximum rating of the transformer.

  • juhanjuhan Member

    @linuxthefish said:

    @juhan said:

    @linuxthefish said:
    Yes, it's fine. 150 volt amps at 150 volts is 1 amp, or around 150 watts depending on the power factor.

    Do you mean the maximum wattage of transformer is 150watt, then my item is only 110watt? It doesn't matter, right?

    Correct, your item draws less current than the maximum rating of the transformer.

    Got it! Thank you so much!

  • MikeAMikeA Member, Patron Provider

    Joined today. Asks about voltage of a kitchen appliance.

  • @MikeA said:
    Joined today. Asks about voltage of a kitchen appliance.

    If this was WHT his vacuum sealer would end up in the microwave and the OP with several overpriced VPS's.

  • juhanjuhan Member

    @MikeA said:
    Joined today. Asks about voltage of a kitchen appliance.

    From where country did it came from?

  • MikeAMikeA Member, Patron Provider

    @linuxthefish said:

    @MikeA said:
    Joined today. Asks about voltage of a kitchen appliance.

    If this was WHT his vacuum sealer would end up in the microwave and the OP with several overpriced VPS's.

    Sorry, my outsourced sales team are paid by the post.

    /s

    Thanked by 1linuxthefish
  • elgselgs Member
    edited July 2016

    The transformer can stand 150VA/120V=1.25A of current, given the input voltage of your device is 120V, 110watt, the maximum current when your device is fully loaded is 110watt/120V=0.917A, which is still smaller than what your transformer allows (1.25A), so I think it's safe to use.

  • @elgs said:
    The transformer can stand 150VA/120V=1.25A of current, given the input voltage of your device is 120V, 110watt, the maximum current when your device is fully loaded is 110watt/120V=0.917A, which is still smaller than what your transformer allows (1.25A), so I think it's safe to use.

    Whoops I read 120 as 150, I stand corrected.

  • pcanpcan Member
    edited July 2016

    The transformer has a 2:1 ratio: if powered at 220V, the output will be 110V. This is still OK for a USA appliance.

    Your load is 110W. Let's make a wild guess that the power factor is 0.85 or better (common values for domestic appliances, as specified by UL and CE regulations), so 110W = 130VA. The transformer nominal power is 150VA. As rule of thumb, a cheap transformer will draw between 5% and 10% of the nominal power, so your worst case total power draw will be 130+15=145VA. Again, this is OK because is less that the maximum transformer load of 150VA.

    You may try to use the appliance. BUT: a regular transformer will not change the frequency. You will force 50Hz on a motor designed to operate at 60Hz. Depending on the specific motor design, you may experience increased operating temperature, because the motor has less iron than required for 50Hz. The slight voltage decrease (110V instead 120V) of most "travel converters" does compensate for this overheating. The downside is a measurable derating of the motor torque.

    In Europe, the cheapest transformers you may source for this application are toroidal 230/55+55v industrial transformers. They cost less than regular "travel converters" or 110/120V transformers, and are easily available at sizes up to 1000 VA.

    For your reference, the cheapest way to supply 220/230V to a purely resistive simple 110V load without electronics, transformers or motors is a diode, from a 1000V 10A or similar rectifier (the rectifier has 4 diodes, only one needs to be connected). This 50 cents solution was widely adopted in the past but is now banned (at least in Europe) because the power factor is lower than the minimum required and it may violate the maximum insulation voltage of switches and wires inside the appliance.

  • @pcan isn't Philippines 60hz?

  • doghouchdoghouch Member
    edited July 2016

    @MikeA said:
    Joined today. Asks about voltage of a kitchen appliance.

    So? Still more interesting that Kimsufi.

    @pcan
    50Hz

    You could (theoretically) convert 220V mains into DC, then back into a 60Hz, isolated, sine-wave inverter. Not the most efficient method, but it should get the job done :)

  • jbilohjbiloh Administrator, Veteran

    Note that your transformer isn't capable of changing the frequency. The USA utilizes 60 hz while much of the world uses 50 hz.

  • pcanpcan Member
    edited July 2016

    @jbiloh: Exactly as you said! In the era of universal electronic power supplies, people forget this and then they are puzzled when the USA-bought kitchen aid or vintage guitar tube amplifier blows up in Europe despite the use of a step-down transformer. Each magnetic material which could be used in a transformer’s core has a limit on how many flux lines it can handle. The lower the operating frequency the more flux lines that are generated. Operating a transformer at 50Hz generates 20% more flux lines than at 60Hz. As the number of flux lines approaches the magnetic material’s limit, the heat in both the transformer’s core and its coil wires increases. This can result in a transformer that exceeds safe temperature levels. AC electric motors have the exact same behaviour. Both of them must be derated by 20% when operated at 50Hz. This means that a 100VA 60Hz transformer will become a 80VA 50 Hz transformer. Several AC electric motors will also rotate 20% slower at 50Hz.

    It is possible to check if a transformer is overheating in a very simple way, because copper resistence will increase with a known rate with temperature increase. Turn on the power switch of the appliance and measure the resistence between the contacts on the mains plug. This is roughly equal to the transformer or motor coil DC resistence when cold. Plug the appliance and wait for a while, then unplug it and measure the resistence again. This value is the "hot" winding value. As long as the hot resistance is not more than 20% increase on the cold resistance, you should be be OK. This figure corresponds with a temperature increase of 50 deg C of the winding, which is a pretty good representation of the hottest part of the transformer.

    @doghouch: the AC50Hz / DC / AC 60HZ is actually done on some expensive industrial converters, but they are very rarely used now. At home, you may do it on the cheap with a 60Hz car battery inverter. The motor control system on new machines is electronic, so no need to fumble around with curmbersome inverters. On vintage equipment (up to the '70), the combination of a electric 50Hz motor and 60Hz alternator was also common; another option was DC power distribution plus a dynamotor. I'se seen it on military NATO equipment, now in surplus stores.

    Thanked by 1doghouch
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