LEM LA-55-P is a bi-directional current transducer which requires +/-15V power supply. According to the datasheet (see below), the current consumption is (10+Is)mA (or, (10+50)mA at Ipn=50A). If the primary current is a sinusoidal current, do you think the current consumptions from the +/-15V rails will be equal? Or, the positive rail tends to supply more current?
Cheers.