why should be the load balanced between all of the 3 phases ?

why should be the load balanced between all of the 3 phases ?

does it have any effect on energy consumption ?

would there be more amps passing through the neutral when any phase is unbalance ?

thanks all of you

An important property of a three-phase balanced system is that the phasor sum
of the three line or phase voltages is zero, and the phasor sum of the three line or
phase currents is zero. When the three load impedances are not equal to one another,
the phasor sums and the neutral current (In) are not zero, and the load is, therefore, unbalanced.
The imbalance occurs when an open or short circuit appears at the load.
Any circuit that does not have all loads with the same impedance in all three branches is an unbalanced circuit.

Typical causes:

Unbalanced distribution of single phase loads
Phase-to-phase loads
Unbalanced 3-phase loads
Unequal impedance of cable runs or distribution lines

Typical results:

Current unbalance in 3-phase induction motors can be several times the value of the voltage unbalance,
leading to motor overheating and loss of efficiency
A major cause of premature motor failure
A NEMA rated motor will exceed its nameplate capacity when phase voltage
unbalance exceeds 2%
Damage to sensitive power electronic equipment
Overheating reduces insulation life, causing premature failure of the motor
VFDs may be damaged or in some cases trip

Neutral conductor current increases .

also, it allows for a constant power. if you find the voltage*current of each phase, you will see a DC term, and a double-frequency term. with 3 phases, the DC term will add, while the double-frequency term will cancel.