Not exactly.epanzella wrote:I'm just guessing here, but I believe LEDs use only half the wave form of 60cycle AC so would that tend to have a strobe effect on rotating machinery?
Household LED lamps use an internal switch-mode power supply to generate low voltage direct current to power the LED cluster. Hence the current flow through the cluster is continuous, not cyclic. Also, light conditioning phosphors are used to give LED illumination a particular color temperature and to diffuse the light output to mimic what a frosted incandescent lamp emits. As phosphors have persistence, any residual flickering is suppressed.
By the way, you should take the life expectancy claims of the LED lamp manufacturers with a grain of salt. The LED cluster is probably good for 50,000 to 75,000 hours total lifetime (no one is certain right now, as the technology hasn't been used en masse for residential lighting for a statistically significant period of time). However, most failures are likely to occur in the power supply, not the LED cluster. This is a failure mode similar to that seen with compact fluorescent lamps (CFL).
Typically, a CFL's fluorescent lamp has a nominal 10,000 to 12,000 hour lifetime, assuming no more than one start cycle in 24 hours. In practice, few CFLs make it past 5,000 hours due to failure of the electronic ballast. The first generation of CFLs that were released in the 1990s used magnetic ballasts, and generally achieved the 10,000 hour lifespan. The desire to make them cheaper led to the use of the electronic ballast.
Another potential problem with LED illumination is heat-induced failure due to use of LED lamps in improperly ventilated fixtures. LEDs of the types used in residential lighting operate at relatively high (by LED standards) power levels and do emit heat. The power supply is not 100 percent efficient and also emits heat. Lacking adequate ventilation, the LED lamp will overheat and fail in short order. In some cases, the power supply may catastrophically fail and stink up the room, trip a circuit breaker, or both. Take a careful look at any fixtures into which you plan to install LED lamps. If they don't have openings at the top to allow heat to escape do not install the LED lamp.