Phase (m)
For single phase induction motor, m=1
Output Power (kW)
o/p = eff * i/p
Voltage (E_ph)
For three phase system, Input voltage could be 440 volts.
Efficiency (eff)
Full load efficiency usually varies between 0.82 - 0.93
Power Factor (pf)
Full load pf varies between 0.82 - 0.92
Input Frequency (f)
(Assumed) change it according to your requirements.
Specific Magnetic Loading (B_av)
B_av = total flux in the air gap /area of flux. For 50HZ machine the value of B_av lies between 0.35 - 0.6 Tesla.
Specific Electric Loading (ac)
ac = total armature ampere conductors / armature periphery at air gap. It varies between 5000 - 45000 ampere conductors per meter.
No of Poles (p)
No of poles must not be less than 2. And must be even numbers.
No of slots/pole/phase
Generally for small and medium size motors the number of slots per pole per phase lie between 3 to 5. The narrow range is 3 to 4.
Rotor Slots (Sr)
Rotor slots must be one of the given calculated values. The difference b/w stator slots and rotor slots should not be equal to 0, p, 2p, 3p, 5p, 1, 2, p+1, p-1, p+2, p-2 to avoid synchronous cusps, magnetic locking, noise and vibrations.
Conductor Current Density
The current density of stator conductor is usually assumed between 3 to 5 A/mm2.
Slot Area Space Factor
space factor = copper section per slot/area per slot. The value of space factor varies from 0.25 to 0.4.
Flux Density in the Stator Tooth (B_t)
Flux density in the stator tooth is between 1.3 to 1.8.
Flux Density in the Stator Core (B_c)
Flux density in the stator core is between 1.2 to 1.4.
Flux Density in the Rotor Tooth (B_rt)
Flux density in the rotor tooth must be limited to 1.8 Tesla.
Flux Density in the Rotor Core (B_rc)
Flux density in the rotor core is between 1.2 to 1.4 Tesla.
Conductor Resistivity (rho)
Auto filled value is for Copper conductor. For any other material need to change this value.
Winding Factor (kw)
For a full pitched windings.
L to Pole Pitch Ratio (L/Pp)
To separate D and L for this product a relation has to be assumed. a) To obtain minimum over all cost 1.5 to 2.0. b) To obtain good efficiency 1.4 to 1.6. c) To obtain good over all design 1.0 to 1.1. d) To obtain good power factor 1.0 to 1.3.
Stacking Factor
Length of the iron core is a little smaller than the overall core length. Stacking factor = ($L_i / L$)
Rotor Bar Current Density
Current density in the rotor bars may be taken between 4 to 7 A/mm2.
Rotor End Ring Current Density
Current density in the end ring may be assume as 4.5 to 7.5 A/mm2
Induction Motor Design
Type: Squirrel Cage Rotor
Given Data
Phase (m) -
Output Power (Q) 30 kW
Power Factor(pf) -
Efficiency (eff) -
Phase Voltage (Eph) - V
Input Frequency (f) - Hz
Poles (p) -
Slots/pole/phase 30
Length to PolePitch ratio (L/tau) - mm
Specific Electric Loading (ac) - A-turns/m
Specific Magnetic Loading(Bav) - Tesla
Stator Tooth Flux Density - Tesla
Stator Core Flux density (Bc) - Tesla
Slot Space Factor -
Conductor Current Density 30 A/mm2
Conductor Resistivity 30 ohm-cm
Winding Factor (kw) 30
Rotor Bar CurrentDensity - A/mm2
Rotor Ring CurrentDensity - A/mm2
Stacking Factor (Sf) -
Calculated Data
Input Power (KVA) 30 KVA
Phase Current (Iph) - A
Synchroneous Speed (Ns) - rpm
Synchroneous Speed (ns) - rps
Pheripheral Velocity (Vs) - m/sec
Flux per Pole ($\phi_m$) - wb
Stator Dimensions
Stator Inner Diameter (D) - mm
Stator Core Length (L) - mm
Pole Pitch (Pp) 30 mm
Stator Slots (Ss) 30
Slot Pitch (Sp) 30 mm
Stator Slot Area (As) - mm2
Stator Tooth Width (W_t) - mm
Minimum Tooth Gap (Tg) - mm
Stator Slot Depth (ds) - mm
Stator Core Depth (ds) - mm
Stator Outer Diameter (Do) - mm
Stator Winding
Conductor Cross Section (a_c) 30 mm2
Conductor Diameter (Dc) 30 mm
Turns Per Phase (Tph) 30 turns
Conductors Per Phase (Zph) 30
Conductors Per Slot (Zs) 30
Total Conductors (Z) 30
Turn Mean Length (Lmts) 30 mm
Winding Resistance per Phase (Rph) 30 ohm
Rotor Dimensions
Rotor Diameter (Dr) - mm
Air Gap B/w Rotor & Stator - mm
Rotor Slots (Sr) -
Rotor Bar Current (Ib) - A
Rotor Bar CrossSection (a_b) - mm2
Rotor Bar Shape -
Rotor Tooth Width - mm
Rotor Tooth Depth - mm
Rotor Core Depth - mm
Rotor End Rings Dimensions
Ring Current (I_r) - A
Ring Cross Section Area (a_r) - mm2