If an electrical appliance is designed to work on US voltage (120 volts) but still doesn't function properly, there could be several reasons for this issue:
Frequency Difference: The voltage in the US is 120 volts at 60 Hz (Hertz), while in some other countries, it might be 120 volts at 50 Hz. Some appliances are sensitive to the frequency of the electricity supply. If the appliance is designed for 120 volts at 60 Hz and is used in a 120-volt 50 Hz system, it may not operate correctly.
Power Variations: The US voltage can sometimes vary slightly from the standard 120 volts. If the voltage supplied to the appliance is consistently higher or lower than the design tolerance, it can cause problems or even damage the appliance over time.
Poor Quality or Damaged Components: Some appliances, especially those made with lower-quality materials or manufacturing standards, might be more sensitive to voltage fluctuations or poor electrical conditions. In such cases, the appliance may fail to work correctly even with the correct voltage.
Compatibility Issues: While most electrical appliances designed for the US market should work fine on 120 volts, there may be some rare cases where a particular model has compatibility issues due to its design or internal components.
Mislabeling or Manufacturing Defects: In some instances, there might be mislabeling of the appliance's voltage requirements, or manufacturing defects may have occurred, leading to operational issues.
Overload or Circuit Issues: If the electrical circuit the appliance is connected to is already overloaded or has electrical issues, it can affect the proper functioning of the appliance.
To troubleshoot the problem, you should first ensure that the electrical supply matches the appliance's specified voltage and frequency. If the issue persists, it's advisable to consult the manufacturer or a qualified electrician to diagnose and resolve the problem. Additionally, always make sure to use appliances with the appropriate voltage converters or transformers when operating them in countries with different voltage standards to avoid potential damage.