Am here in HK with mains at 220v and 60Hz. I would like to buy a device from USA which is only supplied as 110v and 50Hz. This device, a hand held massager, has an internal motor. The manufacturer advises against using a converter but i do not quite understand the total issue. I gather the frequency use of 60 may lead to overheating, as i guess the converter does not change the frequency. Any easy way around this problem and in fact, is this a 'real problem' or only a maker's protection issue? If i only use the device for limited times, say half hour, can i prevent overheating by using higher amp converter? Your ideas welcome.
Step down converter usage
- Thread starter jobin
- Start date
First of all HK uses 50Hz not 60 and the USA uses 120v at 60Hz not 50.
Cheap converter devices should not be used with motors but a true transformer should be OK. Depending on the type of motor it may run slower on 50Hz. Nothing is guaranteed.
A 60Hz motor run on 50Hz is likely to overheat.
Depending on the type of motor, some motors follow the mains frequency to determine the RPM, others are independent of mains frequency, this depends largely on the armature type, if it is a cage type then the speed depends on the rotating field and hence the frequency of the incoming supply, but this should not really be a problem, it is not a clock as such that will drift in time keeping.
Most important issue being the voltage, if a motor is designed for 110V ac then it should never be subjected to as much as 220V it will burn out in a very short time, further more if it is not a mains synchronous or a cage motor then it may even run far too fast and destroy itself.
Most motors used in mains hand held drills for example are not dependent on mains frequency, they have a wound armature, and and a commutator with brushes, their speed is controlled by voltage alone.
A step down transformer rated to the same wattage or more should be used to transform 220V down to 110V. (if the motor rating is say 100watts at 110v then you need to make sure that the transformer needs to be rated to supply 110v at 100VA or just around 1 amp current, ideally a 200VA ( 110v at approx 2 amps) as an example, transformer is more safer but will be more expensive, motors also tend to draw a huge amount of current when starting so by having a twice the rated power, you are covering from this stalled motor condition, but have the transformer fused by an anti -surge fuse of appropriate value to prevent overloading the transformer under stalled condition.
Most important issue being the voltage, if a motor is designed for 110V ac then it should never be subjected to as much as 220V it will burn out in a very short time, further more if it is not a mains synchronous or a cage motor then it may even run far too fast and destroy itself.
Most motors used in mains hand held drills for example are not dependent on mains frequency, they have a wound armature, and and a commutator with brushes, their speed is controlled by voltage alone.
A step down transformer rated to the same wattage or more should be used to transform 220V down to 110V. (if the motor rating is say 100watts at 110v then you need to make sure that the transformer needs to be rated to supply 110v at 100VA or just around 1 amp current, ideally a 200VA ( 110v at approx 2 amps) as an example, transformer is more safer but will be more expensive, motors also tend to draw a huge amount of current when starting so by having a twice the rated power, you are covering from this stalled motor condition, but have the transformer fused by an anti -surge fuse of appropriate value to prevent overloading the transformer under stalled condition.
My understanding is that a 60Hz motor supplied with 50Hz will present a lower impedance, and therefore draw more current than it's designed for.
yes you are right, there will be some extra heating issues due to lower frequency, but this is going to be minute compared to driving the motor with twice the voltage.