CH3
Chapter 3 · Elevators and mine hoists
Vertical transport, where gravity drives the load: counterweights and roping, the four quadrants on a real lift, S-curves and leveling, braking resistors and regenerative drives, the fail-safe brake and safety chain, and the mine hoist.
6 lessons· 190 min
- 01Counterweight, roping and reflected torqueWhy a lift carries a counterweight, how 1:1 and 2:1 roping trade speed for torque, and the static and dynamic torque the motor must supply.30 min
- 02Four-quadrant operationMotoring and generating in both directions on a real lift: the four cases, Tutorial 3.1 worked through, and one Lab III trip traced instant by instant.30 min
- 03S-curves, positioning and levelingJerk and the seven-phase S-curve, what comfort costs in trip time, and how an encoder and hoistway vanes stop the car level with the floor.30 min
- 04Torque at zero speed, braking resistor or regenerationProving torque before the brake opens, what regenerated energy does to the DC bus, and how to size a braking resistor (Tutorial 3.2) or return the energy with an active front end.35 min
- 05The brake, the safety chain and the controllerThe fail-safe brake, the series safety chain and its two kinds of failure (Tutorial 3.3), fault finding by bracketing, and how lift controllers went from relays to microcontrollers.35 min
- 06Mine hoists (extractors)The same four-quadrant principles at the largest scale: drum and Koepe winders, the balanced hoist, the winding cycle and its production rate, drives from Ward-Leonard to regenerative converters, and hoist safety.30 min