Preferably not. Shuttle does not qualify any dimmer model to be used with wire wound transformers due to the possibility of dimmer and/or LED damage. In fact, a number of prominent dimmable LED manufacturers/suppliers issued release notes which state that the LED’s are not to be dimmed when powered from wire wound transformers.

Unless the wattage load on the wire wound transformer is close to the VA rating of the transformer, the back EMF can be very large. If the real load is close to the VA rating, most of the back EMF is only caused by the transformer leakage inductance which is normally only about 1-4% of the total inductance (depending on the size and winding method). The problem with LED is that one would place a “replacement” lamp on the transformer – that is light output replacement, not wattage replacement. For instance, a 200VA wire-wound normally had 4x50W halogen lamps. Now the 4 halogens are for instance replaced with 4x10W LED’s and the 200VA transformer only has a load of 40W which implies that the total circuit now becomes hugely inductive (same with a 1x10W LED on a 50VA) and the power factor deteriorates significantly. When not being dimmed, the much larger energy stored (causing back EMF) is simply returned to the mains without a problem, unless there is a brown-out. During a brown-out, the voltage is momentarily interrupted and it can cause a much higher back EMF to be generated. Fortunately this would generally not cause a problem since it’s for a very short time. If the under-loaded wire wound transformer is however dimmed, the problem becomes significant. Essentially the voltage to the transformer is interrupted during each cycle and the EMF generated will over stress the dimmer and failure will occur unless a dimmer specifically designed for an inductive or so called “motor” load is used.