GENERALLY, responsible motor manufactures do not list the motor voltage as "240V", that is what is referred to as the "distribution voltage". The motor nameplate voltage would be shown as the "utilization voltage" and will say 230V, or better yet, "208-230V". Again responsible motor mfrs, ie those who follow NEMA guidelines when designing for use in North America, will have an acceptable voltage variance of +-10% minimum, without appreciable loss of torque. Utilities, who supply the distribution voltage, are supposed to maintain a +-5% range
So for a straight 230V motor, that means it can accept 230*.9 or 207V as a minimum voltage. The utilitiy can acceptably supply 208*.95 or 207.6V, but by the time that gets even a slight voltage drop from service to load, you will be outside of the motor's acceptable range. That's why mgookin asked about REAL values, not guesses, because this leaves little room for errors and fluctuations without noticeable consequences. In that, you must CAREFULLY read the nameplate data, and by stating it as "240V" you are showing that you did not look very carefully, or that your motor supplier is WAY off base (which often means really cheap junky Chinese motors because many of those bottom feeders have no clue).
If your motor nameplate says "208-230V", the design is a compromise based on a likely scenario wherein the motor winding design is really 220V, with maybe some extra iron to give it a slightly more acceptable range; 198-242V. The idea is based on the concept that 208V tends to be used in smaller facilities where the distance from service entrance to load is relatively shorter, so there is less voltage drop, and that true 240V 3 phase supplies tend not to drift upward very often or very much. These are, again, assumed generalities and there are always exceptions.
Unfortunately, motors designed for use in other parts of the world are generally NOT inclusive of 208V 3 phase, because that exists nowhere but here in North America. Their real design is actually 230V 50Hz, then they will often say "50/60Hz" based on a slight de-rating of the mechanical power (kW) of the design. That's because if you have a motor designed for 230V 50Hz and give it 60Hz, it spins 20% faster, but produces 17% less torque. So the motor is designed for the greater power rating, but is nameplated at the lower one and given the "50/60" label, usually without the back story details because the 60Hz rating is still valid, it will just actually be capable of slightly more kW at 50Hz than what they list and that's OK.
However, this IEC design is NOT typically suitable for operation on 208V, it is something that IEC motor designers do not have to think about. Since you say that your motor is rated in kW instead of HP, it's likely that it is an IEC motor, and even if it says "50/60Hz" on it, there will be no added lower tolerance. You should boost it to be safe.
