Overload Relay Sizing for Star-Delta Starters
How to size a thermal overload relay for a star-delta starter using the FLC divided by √3 delta-leg current calculation.
MPCB Sizing for Star-Delta and Soft Starting
How to size an MPCB's thermal dial and magnetic trip for star-delta and soft-start motor circuits, including the 58% winding-current rule and soft-starter co...
How to Size an RCBO for a Final Circuit
How to size an RCBO for a final circuit: matching In to design current and cable capacity, setting IΔn and type by load, and checking discrimination with the...
VFD Sizing for Constant vs Variable Torque Loads
How to match a VFD's Normal Duty or Heavy Duty overload rating to constant-torque and variable-torque loads, with the sizing steps, overload-margin formula, ...
Soft Starter for High-Inertia Loads: Sizing and Start Profile
How to size a soft starter for a high-inertia load: the torque-vs-voltage sizing trap, WK² acceleration time, current limit versus torque control, and AC-53a...
How to Size an MCB for a Circuit
How to size an MCB using the Ib ≤ In ≤ Iz coordination rule, curve matching, and breaking-capacity verification, with a worked example.
How to Select and Size a Soft Starter for a Motor
How to size a soft starter correctly by full-load current, IEC 60947-4-2 duty class, starting torque against the load, control method, wiring topology and pr...
