In Three Phase supply sustem, If any induction revolving 
equipments distribution or loading ,should take even 
Amperes (Loading), Neutralaizing also should 0 Volts  - Its 
called Balanced Load . Unbalacing is taking load diffent 
Amperes or Neutralizing getting some volts are called 
Unbalanced Load.

well thanks for the help,,, but plz can u elaborate it more

in three phase if all phasxes have same load and nuetral 
current is '0' its ballance load and if is more than then 
its unballance load
ir+iy+ib=0

in three phase if all phasxes have same load and nuetral 
current is '0' its ballance load and if is more than then 
its unballance load
ir+iy+ib=0

If we say it is a balanced system/load it has to obey to 
points
1.constant power transfer to the load.(should not vary with 
time)
2.no nuetral current.
If it does not obey any of the above we can consider as 
unbalanced.