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What happens when a 120v 15A AC motor is connected to a 220V supply?

In case this is a destruction, what should be the power rating of a converter that is to be used?

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  • \$\begingroup\$ Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design. \$\endgroup\$
    – shimofuri
    Feb 19, 2015 at 11:07
  • \$\begingroup\$ I wish I could understand what that meant! Thanks anyways. N sorry \$\endgroup\$ Feb 19, 2015 at 11:11
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    \$\begingroup\$ I'd check with the manufacturer but it's unlikely to be OK. You can get isolation step down transformers for this and it looks like you need one with a 2kVA rating minimum. Though the only reasons not to use something bigger are cost and weight. \$\endgroup\$ Feb 19, 2015 at 11:47

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It's very possible that it will be damaged. Most probably on its starts, where there is a higher current drawn. If not it will run at higher speed with higher current and so it will overheat. It may get hotter and hotter to finally burns.

You will need a transformer with 2:1 ratio (240V / 120V) and power of 1.8kVA (120*15). Remember to also specify the frequency when you will buy the transformer!

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    \$\begingroup\$ In the UK and probably the rest of Europe, any builder's merchant or tool store will be able to sell such a transformer, with connectors, ready to use. \$\endgroup\$
    – user16324
    Feb 19, 2015 at 12:44
  • \$\begingroup\$ Here in Brazil the ratio in fact it's 1:√2 since the standard voltages are 220 and 127. So it will depends on where u are. \$\endgroup\$ Feb 19, 2015 at 15:42
  • \$\begingroup\$ Pedro, the problem with AC motors running on wrong voltage is not overcurrent. The problem is a too high voltage is driving the core into saturation. That's the same as with transformers as asynchronous AC motors are in fact transformers in disguise. So, you may stay much below the rated current at the higher voltage, and still the whole thing overheats. \$\endgroup\$
    – Janka
    May 20, 2017 at 17:03

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