Not if the CPT is external to the warranteed equipment.But since the existing design uses one of the three phase conductors to power their controls, installing the CPT would mean modifying the design. Personally, that's likely what I would've done. But I can also understand the risk of voiding the warranty.
BTW, if this is truly equipment design for 240/120V 3? 4W, will either have to use the 1? autotransformer setup, or a 1:1 3? isolation transformer... assuming the equipment has only 4 power supply terminals.