**Alternators**

**Important Formulae to remember**

## Topic

## Examples

- A 12 pole 500 rpm, star connected alternator has slots with 15 conductors per slot. The flux per pole is 0.02 wb .The winding factor is 0.97 and pitch factor is 0.98. Calculate the phase EMF and line EMF
- A 3∅, 6 pole star connected alternator has an armature with 90 slots and 12 conductors per slot, it revolves at 1000 rpm, the flux per pole being 0.05 wb. Calculate the line value of the EMF generated, if K_d = 0.96 and K_p = 0.97
- A 6 pole Υ connected, 3phase, 50Hz alternator has 12 slots per pole and 4 conductors per slot. A flux of 25mwb is sinusoidally distributed along the air gap. Determine the (i) Phase EMF (ii) Line EMF. Assume coils are full pitched and winding factor as 0.96
- The stator of a 3∅, 8 pole, 750 rpm alternator has 72 slots, each of which contains 10 conductors. Calculate the RMS values of EMF per phase is flux per pole is 0.1 wb sinusoidally distributed. Assume full pitch coils and Kd as 0.96
- A 3Φ, 4 pole, 50Hz star connected alternator has 36 slots with 30 conductors per slots. The useful flux per pole is 0.05 wb. Find synchronous speed and line voltage on no-load. Assume Kw=0.96
- A 2 pole, 3∅ running at 3000 rpm has 42 slots with 2 conductors per slot. Calculate the flux per pole required to generate a line voltage of 2300 V. Assume Kd=0.952, Kp=0.956. The armature is star connected
- A 6 pole, 3∅, 50 Hz alternator has 12 slots per pole & 4 conductors per slot. The winding is 5/6 full pitched, a flux of 25 mwb is sinusoidally distributed along the air gap. Determine the line EMF, if the alternator is star connected
- A 3∅, 4 pole, 50 Hz star connected alternator has an armature with 2 slots per pole per phase and 40 conductors per slot. Calculate the EMF generated if the flux per pole is 0.06 wb distributed sinusoidally