What should be the correct way to ground a PLC Panel? Is it necessary to instal an isolation transformer for the grounding of the PLC panel?
Or can we bring a ground conductor (isolated ground) directly from the 120V distribution Panel and connect it to the ground bus of the PLC panle; and then...
The problem is that motor FLA in NEC are calculated on 460V, while the transformer secondary is 480V. So current at 480V will be little less than the current at 460V.
As of motor starting, if the full load current of the transformer is at least six times larger than the FLA of the largest...
Should we use HP or BHP for the calculation of loads? For example a 20HP load has a BHP=18. We have to size transformer for eight 20HP motors.
If we take HP of motors then: 8*20*0.746 = 119.36 kVA (150kVA transformer required)
But if we take BHP of motors, then: 8*18*0.746 = 107.42 kVA...
