Looking to take advantage of price difference to import a washing machine from China - rated 220 volts 50 hertz to Kenya where we use 240 volts 60 hertz. Our supply also tends to be unstable with brownouts and surges. What would be the implication of using the device here?
A BLDC motor is, by definition, electronically controlled, so frequency range is not a matter of the motor itself but of its control electronics and power supply. If the power supply is either a simple rectifier or a PSMPS (vulgo inverter), a slightly higher mains frequency should not matter much (a significantly LOWER mains frequency might, though!). HOWEVER, this is something to best ask the manufacturer about.
An explicitly 220V rated device on a 240V mains can be trouble, though - there are nominal minimum/maximum voltages for a given device, and also for a given power grid (often around +/- 10% - but that is up to your national grid). In a pessimal case (grid at maximum voltage allowed) the device can fail or wear more quickly than intended.
"Surges" and "Brownouts" are even more troubling, you would have to measure what the actual voltage during such events is and make sure the device can handle these (undervoltage in continued use can be bad for a PSMPS, not just overvoltage!). BTW, do not use small "plug in" surge protectors for that application: they are meant to deal with short surges from electrical storms and grid trouble, not constant overvoltag. The device you would need is called a voltage stabilizer and more large, complicated and expensive.
BLDC ? Normally when talking BLDC my thoughts go to Motors you are talking Brushless Direct Current [Brushless DC] motor. Which means that motor is controlled differently - Voltage is converted to DC and you either have a direct connection where voltage controls RPM or a VFD style motor controller that determines RPM.
Now back to that BLDC motor - it would be using a Controller to operate that motor - and as such depending on what type of controller and how its supply circuits are it could over drive the motor - burn up both motor and controller.
In a washing machine the Motor is generally AC , but not always anymore.. Now on to the deal between 50Hz AC and 60Hz AC at 60 Hz your motor will run faster about 20% faster, you will use more power as well [see next paragraph for important information] - approximately 20% more.
You will also draw more current and might exceed the FLA [Full Load Amps] of the motor - what does that mean .. it means you will let the smoke out of the motor and the aroma will not be pleasant - nor the expense. They have yet to create any device to put the smoke back into a motor once it is blown and fried so you would need to buy a new motor. Now frying a motor if it goes up in flames while you went outside somewhere - perhaps your home burns with it.. is it worth saving a few pieces of silver IMO no.
Given that the unit you want is made in China I would imagine the FLA barely meets the requirements for the 50Hz threshold - so at 60Hz you would exceed the FLA.
In short - Don't do this..
EDIT 12/13/2017 If you insist on doing this : You can solve all the problems surges, brownouts and the voltage / frequency issue in another way.
Purchase a battery backup unit or Inverter of sufficient amperage to support operating your washer. 240VAC/60hz input 220VAC /50hz output.
Of course that might defeat your intent to save on costs..