Operating 60Hz Electrical Appliances at 50Hz

As a general rule it may be unsafe to operate 115V 60Hz rated appliances at 115V 50Hz. Operating 60Hz appliances at 50Hz may result in excessive heat buildup in transformers or in certain types of electric motors.

If you wish to safely operate 115V 60Hz appliances at 115V 50Hz then the following steps can be attempted:

  1. Contact the manufacturer of the appliance. It may be possible to safely operate at 50Hz with the manufacturer's approval.

  2. See if an alternate 240V 50Hz or 115V 50Hz power supply or electrical motor is available. Some manufacturers sell the same appliance or electric tool in many countries around the world and may be able to retrofit the power supply or electrical motor to 240V 50Hz. Some regions of Japan have 100V 50Hz supplies while others have 100V 60Hz supplies so it is not uncommon for Japanese manufactured electrical devices to have 50Hz solutions.

  3. It is possible to purchase 60Hz sine wave power systems that take 240V 50Hz on input and produce 115V 60Hz on output. These solutions are generally very expensive, and it is usually more cost effective just to replace the tool or appliance. See here for a high current frequency conversion solution.
If these solutions, for one reason or another, do not work then there are only two further choices: dispose of the appliance or tool, or attempt to operate the appliance or tool at 50Hz and in the process potentially create a situation where the power supply or the motors in the appliance or tool are rendered non-operational.

If the decision is made to destructively test a 115V 60Hz appliance or tool at 115V 50Hz then the following information may be of help:

  • Potentially destructive testing of 115V appliances can lead to smoke, sparks, flame and can create an electrocution hazard.
  • Cheap internal 115V 60Hz transformers in electronics may overheat if run at 50Hz.
  • Most modern switching power supplies can run at 50Hz or 60Hz, however it would be unusual for such a power supply to not be labeled as 50/60Hz.
  • "Universal" electric motors generally do not care about power frequency. A 115V 60Hz universal motor can typically be expected to operate correctly at 50Hz or even at 115V DC. Many inexpensive power tools use universal motors, likewise many vacuum cleaners and household kitchen appliances use universal motors.
  • Universal motors can be usually be identified by both of the following features:
    1. The use of replaceable carbon brushes in the motor. These will be identified in the spare parts section of the appliance or tool's user manual.
    2. Universal motors tend to be very loud.
  • 115V 60Hz induction motors:
    • May experience excessive heat buildup if run at 50Hz.
    • Will operate at fewer revolutions per minute. When a 60Hz induction motor is operated at 50Hz the motor will run at 5/6ths of its RPM's at 60Hz.
    The heat buildup may cause failure of the motor. To avoid heat buildup in induction motors ensure the voltage-to-frequency ratio is preserved. This means that a 115V 60Hz induction motor should see 96V to maintain the voltage-to-frequency ratio at 50Hz. Hammond make a 115V->95V 2000W step down autotransformer, the 168J. Using the 168J implies that an appropriate 240V->115V 50Hz transformer is available.