A 2 Ton AC typically draws around 2000-2400 Watts of power. This means that it will draw around 2-2.4 KW of power when it is running.
A 3KW electric meter can only handle a maximum of 3000 Watts of power. This means that if the AC is drawing 2-2.4 KW of power, it will overload the meter and cause it to trip.