How can a small motor lift a heavy car, and what stops the car if it ever goes too fast?

motormachine brakedrive sheave, 6 rope groovesdeflector sheavegovernor (speed checker)hoist ropes (6)guide railcounterweight 1,360 kg12 filler weightsrail bracket and beamgovernor ropecar + load 1,000 kgcounterweight bufferbalance chainsafety (grips the rail)bufferpit pulleymachine roomcontrol cabinetlanding doorspit123
car
at floor 1 · 0.00 m up
speed
0.00 m/s · 0.00 m/s²
sides
car 1,000 kg · counterweight 1,360 kg
ropes
car side 9.8 kN · counterweight side 13.3 kN
motor
off
with no counterweight
-
energy this trip
-
brake
on, holding 3.5 kN
governor + safeties
ready, trips at 1.20 m/s

Press the steps in order, or press Auto. It runs in real time. Watch the readings: how hard does the motor pull, with and without the counterweight?

Elevator facts from the U.S. Mine Safety and Health Administration (Elevator Safety: Give the Miner a Brake: 6 to 8 ropes, counterweight = car + about 45% of rated load, governor trips 15 to 25% over rated speed) and the National Academy of Engineering (The Evolution of Elevators). Physics from OpenStax College Physics 2e (4.3 Newton's second law, g = 9.80 m/s², 2.5 motion equations) and University Physics 1 (7.4 Power, P = Fv). Rope mass and friction are left out. Car and load masses, speeds, the safety grip and all sizes are example values. Drawn to scale with the Anatomy kit (MIT license).