American 115V to British 240V transformation

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Folkner

Member
I am in England right now, where the standard residential power supply is 240V. I need to run an appliance I brought from the US ( electric velobinder GBC), which operates at 115V, 3.1A Max. I am using 240V to 120 V voltage converter, which can be used with appliances with power up to 100W. When I switch on the appliance, it produces quite loud buzzing noise but it doesn't operate as normal. What can be the problem ?
 

BarryO

Member
Well, (115V, 3.1A) > (100W).

I hope you're not an electrical professional, or your career may be very short-lived! ;)
 

Folkner

Member
Thank you for your comments ! It ( specification ) says 3.1A Max. I would assume that it uses up to 3.1A when it actually punches the wholes in sheets of paper ( that what it is supposed to do ). If 240 -> 120 V, 100W converter is overloaded, why there is a buzzing noise from a velobinder and not from the converter ?
 

robbietan

Senior Member
Location
Antipolo City
uk has 50HZ compared to us 60HZ. probably the noise is coming from the velobinder's motor running at 60HZ, instead of its usual 50HZ.
BTW, what is the voltage converter you are using? electronic? best take out an RMS meter so that you can see what kind of wave the converter is actually providing.
 

beanland

Senior Member
Location
Vancouver, WA
Buzzing...

Buzzing...

Folkner said:
Thank you for your comments ! It ( specification ) says 3.1A Max. I would assume that it uses up to 3.1A when it actually punches the wholes in sheets of paper ( that what it is supposed to do ). If 240 -> 120 V, 100W converter is overloaded, why there is a buzzing noise from a velobinder and not from the converter ?

Does the tool use a solenoid or motor? If the load of the punch exceeds the converter and the punch is solenoid operated, it will not have enough force to punch the paper. So, it hits the stack of paper and rattles. Same problem could happen if motor-operated. You need a bigger converter.
 

charlie b

Moderator
Staff member
Location
Seattle, WA
Occupation
Electrical Engineer
This might not help with your problem, but it is a story that I think is worth sharing.

I am flying to London on Monday, and I went out earlier this week to buy a converter. At one general purpose electronics store, the sales assistant (under 20 years old, I think) had absolutely no idea what he was talking about. There are two types of these converters, he said. That proved to be true. One is for heating appliances (e.g., hair dryers), and the other for computers or TVs, or similar electronic devices. That also proved to be true. But then he said that if you plug a computer into the one designed for hair dryers, it would destroy the computer. His reason was that the volts would be OK for the computer, but the amps would be too high. I was incredulous. I started to explain what volts and amps were, but I quickly saw the ?deer in the headlights? look, and gave up.

Then I noticed that the package for the heating appliance type of converter did say that it should not be used for computers. That really threw me. I could not imagine how a computer, which draws far less power than a hair dryer, could be damaged by a device that has a higher power rating than the computer needs.

I wound up buying a transformer (240-120) from another store. The sales assistant there gave me a reasonable explanation for the anomaly I describe above. He said that the converter devices intended for heating appliances are rated for short term usage only. You generally need but a few minutes to dry hair. But you would leave a TV running for hours, and you might leave a computer plugged in and recharging overnight. That would cause an overheating failure of the converter, and would then place the electronics at risk.

My guess about your buzzing problem is that you are drawing more current than the converter can handle. That is causing a large voltage drop, and buzz comes from the motor's reaction to the low voltage.
 

rickjus

Member
Location
Tampa, Florida
Here is a link to everything you need to know about transformers/converters/adapters...

http://users.pandora.be/worldstandards/electricity.htm


"Transformers and converters only convert the voltage, not the frequency. The difference in cycles may cause the motor in a 50 Hz appliance to operate slightly faster when used on 60 Hz electricity. This cycle difference will cause electric clocks and timing circuits to keep incorrect time: European alarm clocks will run faster on 60 Hz electricity and American clocks will lose some 10 minutes every hour when used in Europe. However, most modern electronic equipment like battery chargers, computers, printers, stereos, DVD players, etc. are usually not affected by the difference in cycles and adjust themselves accordingly the slower cycles."

In general your device (I'm assuming is motor driven) is cycling slower 50HZ than it is intended to 60HZ. In addition, the transformer (probably a converter) is too small (undersized) to run this device as intended.
 

c-h

Member
The explanation for Charlie's mystery:

The small converter for heaters only works from a higher to a lower voltage.

It simply contains some electronics to chop the voltage: Full 240V voltage for a little while, then a pause with no voltage, then the full 240V again. The timing is chosen so that the amount of energy let through is the same as it would have been at normal 120V.

Your computer won't like that kind of power.
 
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