To be honest, escalators don’t usually surprise us. Most of the time, they work quietly, carrying people up and down without problems. But sometimes, something unexpected happens — a brand-new escalator suddenly stops, or an older one starts shaking, making passengers uncomfortable.
Because we are not only a manufacturer but also a technical support partner, maintenance companies often call us when they face these problems. We’ve helped fix issues that at first seemed big, but were solved with the right diagnosis and a simple change.
In this post, I’ll share two real cases from our partners: one where a new escalator refused to run, and another where an old one gave a rough ride. Both show how a small detail can cause big trouble — and how our support can get everything running smoothly again.
1. Speed Monitoring Device Fault – Escalator Cannot Run
Problem A GRF30-100 escalator had just been installed and handed over for use. Soon after, the customer reported that the escalator would not start. The PLC display showed an “overspeed/underspeed” fault. The local maintenance team suspected unstable power, a damaged PLC, or a faulty pulse sensor — but after checking each one, all were working fine.
Cause On this model, the speed monitoring device is mounted on the brake of the drive motor. A flywheel and magnetic block work together to send pulse signals to the pulse sensor, which then sends them to the PLC. If the speed is more than 1.2 times the rated speed, the system will cut power to meet national safety standard GB16899-1997. After our remote technical support guided further inspection, the team found that the pulse sensor and magnetic block were misaligned, and the vertical gap was too large. This caused the PLC to receive incomplete signals, mistakenly detecting overspeed and cutting the power.
Solution We guided the team to loosen the pulse sensor, align it with the magnetic block through the service hole in the flywheel, and adjust the gap to 5 mm. Once tightened, the escalator ran normally again — without replacing any parts.
2. Worn or Loose Drive Chain – Poor Riding Comfort
Problem An older escalator had begun to shake during operation, making passengers uncomfortable. The handrail was also moving slower than the steps.
Cause Most escalators use chain drives between the drive motor and the main drive shaft, as well as between the handrail drive shaft and the main drive shaft. Over years of use, the chains and sprockets wear out. The chain no longer sits in the correct position on the sprocket, and in severe cases, it may climb up or jump over the teeth. This causes step jerking and handrail delay.
Solution We advised our maintenance partner to:
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Check the main drive chain and sprockets, and replace if worn.
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Adjust the drive motor base cam to give the chain proper tension.
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Check and replace the handrail drive chain and sprockets if needed.
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Adjust the handrail tension bolt for correct tension.
After replacement and change, the escalator ran smoothly again and riding comfort was restored.
Conclusion
As a manufacturer, we don’t just supply equipment — we provide fast fault diagnosis and modernization advice to help our partners reduce downtime, avoid unnecessary part replacements, and improve passenger experience. If your escalator faces similar problems, our technical team is ready to help.
