3-Phase to 5-Phase Transformer: Design & Protection

3 PHASE TO 5
PHASE
TRANSFORMER

WHY 5 PHASE OVER 3 PHASE
Multiphase machine has a greater fault tolerance compared to
its 3 phase counterparts if one phase of the 3 phase machine
becomes open circuited so single phasing occurs . It may
continue to run, but will require external means for starting
and must be massively derated. If one phase of multiphase
machine becomes open circuited it will self start and will run
with only minimal derating
Another reason for multiphase variable speed drive is the
possibility of reducing the required rating of the power
electronics components for a given output power of the motor,
when compared to a 3 phase motor.

Utilization of multiphase motor drives also enables
improvement in the noise characteristics when compared to three
phase motor drives
The stator excitation in a multiphase machine produces
a field with a lower space-harmonic content, so that the
efficiency is higher than in a three-phase machine.
Reduction in stator joules loss achieved by increasing the
number of phases beyond 3
No of phase - 5 6 9 12 15 18
Stator cu loss - 5.6 6.6 7.9 8.3 8.5 8.8
reduction (%)
wrt 3 phase

FACTS ABOUT TRANSFORMER
It works on the principle of mutual
induction
It is a shell type of transformer
Transformation ratio is unity
Phase difference between each phase is
72 degrees

CONSTRUCTION & WORKING