Voltage question

Would a component from Japan that is rated 100 volts be safe to use here on 110-120 volts,

Safe? That's not the problem. The problem is you will be feeding the piece of equipment at a much higher voltage than the equipment was designed to be operated at. Will it work? Yeah,.... But you will shorten its' life.


General rule is + or - 10% of the manufacturer’s recommended voltage.
100Vac x 10% = 110Vac.

The average residential AC mains voltage in the US is 119Vac - 122Vac. 120Vac nominal probably being the most common.

The cheapest way to reduce the voltage to 100 volts is with a Buck auto-transformer.
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winoguy17 OP655 posts

03-02-2020
6:28am

As stated in the OP ,its rated 100v.


If I do pursue this I would probably look into stepping down the voltage. Where is a good place to look for one? Thanks again.

I would first check the AC mains voltage with a volt meter at the wall outlet to see what you have. Check it a few times through the day to get an average reading, measurement. Does it average 120V - 123V? Does it average 118V - 120V? Or maybe 119V - 121Vac?

Be careful of buying a cheap so called voltage converter that says to size the unit at two times or more the rated load of the item that will be plugged into it. You might want to also read the customer reviews on the unit if there are any. I have a feeling the manufacturer of the really cheap so called voltage converters are under sizing the wire gauge used in the winding/s.

Here is a step down transformer manufacturer I found, searching the Agon archives, from an Agon member that posted on a thread. I used his link and found these two transformers that should meet your AC mains voltage. The smallest wattage transformer I could find is 300 watt.

https://acupwr.com/collections/japan-to-usa-transformer-converter-use-100-volt-appliances-in-110-vol...

This Link is from a retail seller, I believe.
https://www.bhphotovideo.com/c/product/964851-REG/acupwr_ajd_300_ctoc_japan_to.html.
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@winoguy17 

Just to be clear, you need to select a step down transformer (SDT) that best matches your wall AC mains voltage. Again you need to check your AC mains voltage at the wall outlet.
 
If your mains voltage average is 120Vac or less then a 115-120Vac to 100V SDT would average an output closest to 100Vac.     
Example  
  https://www.bhphotovideo.com/c/product/964851-REG/acupwr_ajd_300_ctoc_japan_to.html.      
If the wall outlet mains voltage is higher than 120V, say 122V, then a 115-120Vac to 100Vac SDT would not be a good choice, imo.  The output voltage of the SDT would be higher than 100Vac.

 
 If the mains voltage averages higher than 120V, say 122V, maybe 123V, then the  125Vac to 100Vac SDT would be a better choice. The average output voltage of the SDT would be closer to 100Vac.      
 Example         
https://acupwr.com/collections/japan-to-usa-transformer-converter-use-100-volt-appliances-in-110-vol...  


If you can find a SDT that is rated at *120Vac* to 100Vac that would be fine for a mains voltage that ranges from 118Vac - 122Vac.  
If the mains voltage is below 120Vac then the SDT would output slightly below 100Vac. With a mains voltage above 120V the SDT output voltage would be slightly above 100Vac.

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