Escalators move on a pair of chains that looped around two pairs of gears. An electric motor turns the drive gears at the top that rotates the chain loops. High horsepower motors are being used for escalators. The escalator is provided with number of control devices for a smooth and safety run. Handrail safety guards are provided to stops the escalator immediately when a hand or other object is caught in the handrail inlet. Broken drive-chain safety device stops the escalator if the drive-chain stretches or breaks and prevents the steps from dropping. Electric circuit protection devices are provided with an automatic circuit breaker to protect the escalator circuitry and power supply parts.
Electromagnetic brakes brake the motor smoothly by a spring force action if power fails or any safety device is activated. Fire shutter interlocked device stops the escalator when interlocked fire shutter near the escalator is activated. Comb plate switch stops the escalator if any matter is caught between a step and the comb or if a step collides with the comb, so that a horizontal force is exerted along comb plate.
