· For Cu Wire Current Capacity (Up to 30 Sq.mm) = 6X Size of Wire in Sq.mm
Ex. For 2.5 Sq.mm = 6×2.5 = 15 Amp, For 1 Sq.mm = 6×1 = 6 Amp, For 1.5 Sq.mm = 6×1.5 = 9 Amp
· For Cable Current Capacity = 4X Size of Cable in Sq.mm, Ex. For 2.5 Sq.mm = 4×2.5 = 9 Amp.
· Nomenclature for cable Rating = Uo/U
· where Uo = Phase-Ground Voltage, U = Phase-Phase Voltage, Um = Highest Permissible Voltage
1HP = 0.746
KW1KWH = 3.6 MJ
Current Capacity of Equipment
· 1 Phase Motor draws Current = 7Amp per HP.
· 3 Phase Motor draws Current = 1.25Amp per HP.
· Full Load Current of 3 Phase Motor = HPx1.5
· Full Load Current of 1 Phase Motor = HPx6
· No Load Current of 3 Phase Motor = 30% of FLC
· KW Rating of Motor = HPx0.75
· Full Load Current of equipment = 1.39xKVA (for 3 Phase 415Volt)
· Full Load Current of equipment = 1.74xKw (for 3 Phase 415Volt)
· Earthing Resistance for Single Pit = 5Ω, Earthing Grid = 0.5Ω
· As per NEC 1985 Earthing Resistance should be < 5Ω.
Minimum Bending Radius
· Minimum Bending Radius for LT Power Cable = 12 x Dia of Cable.
· Minimum Bending Radius for HT Power Cable = 20 x Dia of Cable.
· Minimum Bending Radius for Control Cable = 10 x Dia of Cable.
· Current Rating of Transformer = KVA x 1.4
· Short Circuit Current of T.C /Generator = Current Rating / % Impedance
· No Load Current of Transformer =< 2% of Transformer Rated current
· 4No. earth pits per transformer (2No. for body and 2No. for neutral earthing),
· Diesel Generator Set Produces = 3.87 Units (KWH) in 1 Litter of Diesel.
· Requirement Area of Diesel Generator = for 25KW to 48KW = 56 Sq.meter, 100KW = 65 Sq.meter.
· DG greater 1000kVA can either be in a canopy or skid mounted in an acoustically treated room