Two related effects
Flicker is a perception of light instability. The stroboscopic effect alters the perception of a moving object when light varies over time. A rotating part may appear slower or even stationary. These phenomena form part of workplace lighting assessment and cannot be resolved simply by increasing lux levels.
Where they may occur
Behaviour depends on the light source, its power supply and dimming systems. A luminaire may behave differently at full output and when dimmed. Review the installation in its actual operating modes. An LED label alone does not guarantee the absence of temporal variations relevant to the workstation.
Machinery risks
An impression of stillness must never be used to decide that machinery is safe. Before intervention, follow the appropriate stopping and energy-control procedure. Improved lighting complements guards and lockout, without replacing them. This is particularly important for lathes, fans and other components with periodic motion.
Investigating a complaint
Record when it occurs, which luminaires are operating and whether it coincides with dimming, equipment start-up or particular tasks. A phone video may show bands but can also introduce camera artefacts; it is not a conclusive measurement. Technical verification needs suitable instrumentation and criteria for temporal variation, alongside listening to affected people.
A lamp-replacement example
In a hypothetical workshop, lamps are replaced without changing the electrical installation. Some people notice unusual motion in a shaft. Review checks power-supply and dimming compatibility, characteristics of the new source and operating conditions. While investigating, control access risks around the equipment; altered perception must not become accepted as normal.
Criteria and follow-up
Luminaire selection must consider the task, not only energy use and power. After correction, review different dimming levels and the conditions in which the problem occurred. Document what changed and how it was verified. Workplace regulations and applicable technical specifications determine the specific requirements.
