Using normal constant current drivers, the total power consumed by the motor at rest is always equal to the square of the phase current times the phase resistance (this is because sin^2 + cos^2 = 1). So 1.5 x 1.5 x 1.4 W in your example. The drivers are not 100% efficient, also there may be some iron losses because of the chopper drive, so the actual power taken from 24V will be somewhat greater than this.
When the motor is moving, and especially when it is accelerating or otherwise driving a load, the power consumption will be higher because of the back emf of fhe motor. So it's hard to be precise about the powet requirement.
When the motor is moving, and especially when it is accelerating or otherwise driving a load, the power consumption will be higher because of the back emf of fhe motor. So it's hard to be precise about the powet requirement.