Power and machines · In the CV

Star-Delta Motor Starter

Built a starter that lowers the starting current of a three-phase induction motor.

MCB
magnetic contactors
timer
thermal overload relay

About

A hardware star-delta starter built with magnetic contactors, a timer, overload protection and indicators for smooth control of a three-phase motor.

Photos and video

Star-delta starter wired on a wooden board: a three-pole CHINT circuit breaker, three contactors (one with a timer block on top), a green push button on a DIN rail and a terminal strip, connected with red, yellow and black wires. — Starter hardware: circuit breaker, contactors with a timer block, push button and terminal strip.

Hand-drawn connection diagram on paper: lines L1, L2 and L3 run through the MCB, main contactors and O/L to the motor windings U1-U2, V1-V2 and W1-W2, with Δ contactors and Y contactors; notes on the right list the standard Δ connections. — Hand-drawn connection diagram of the star-delta starter.

Video of the starter hardware (10 s). (6.4 MB)