How to choose CT ratio, accuracy class and VA burden for an 11kV panel, with a worked burden calculation and why an oversized VA rating hurts metering.
Failed rolling mill DC motor? When to rewind, fit a new DC motor or convert to AC with a VFD, and why the DC nameplate can undersize the AC motor by half.
Neutral earthing for an 11 kV plant: when a neutral grounding resistor (NGR) beats solid or resonant earthing, and what an NGR specification must include.
DGMS approval, CIMFR (CMRI) test reports and CCE/PESO approval explained: what each covers for flameproof motors and panels in underground mines in India.
Power factor correction on the 11 kV bus: when an HT capacitor bank fits, how to avoid harmonic resonance, and which detuned reactor to choose and why.
Transformer testing before energising: which routine and type tests to witness at works, which to repeat on site, and the oil test results to insist on.
A squirrel cage motor on a VFD suits most crane hoists. Slip ring motors still win where crushers, mills and deep hoists need high torque at low current.
