CP SB1 User Manual
64
5.1.5 Safety Aspects
Feeding currents of several amps through a coil rated at hundreds of Henries
causes a high magnetic energy to be stored in the coil inductance. If the
measuring circuit was interrupted without discharging this energy, very high
voltages would be induced which would be very dangerous for the operator and
the test system. An automatic discharge of the coil inductance after
measurement is automatically carried out as it is essential for safe operation,
though while switching from one tap to another, a discharge cycle is not
necessary and this saves a lot of time.
5.1.6 Delta-Connected Windings
For delta-connected windings, R12, R23 and R31 cannot be measured directly
but are calculated from the measured Ra, Rb and Rc values.
Ra = R1 + R2
Rb = R2 + R3
Rc = R3 + R1
Y connection without Neutral:
Rc - Rb + Ra = 2 R1 => R1 = (Rc + Ra - Rb) / 2
Ra - Rc + Rb = 2 R2 => R2 = (Ra + Rb - Rc) / 2
Rb - Ra + Rc = 2 R3 => R3 = (Rb + Rc - Ra) / 2
Closed delta winding
To Next Page
Loading...
General