Lift Elevator motor plant room controller selector Otis

[bearchoirfan]

At the end of the video I can see the motor running at a steady slow speed. This looks very much like a double-speed or triple-speed AC machine. But there's clearly the sound of the MG-set. So does DC models also have such a steady slow mode just before halting like AC models?

[jorologo]

@bearchoirfan

For a long long long time DC motor speed control was the best form of regulation over AC motors with 2-3 speed windings.

Today AC motors are controlled by Variable Frequency drive units. Some of these units can control the speed as good or even better than DC Ward Leonard control. Variable Frequency is known to be more energy efficient over DC control.

In recent years elevators that use traditional M.G sets are being removed to be replaced with these control converters.

[V8Jagnut]

nice. just the way it should be.

[mrmattandmrchay]

Great stuff, this is more like the stuff that I want to see!  Excellent video. If I was in this room then I'd be in there for hours trying to work out the role of each relay!