Custom motor projects go faster and land closer to right-first-time when the buyer arrives with a clear picture of the application: duty cycle, mounting envelope, electrical supply, ambient conditions, and any regulatory requirements the finished unit needs to meet.
From there, the engineering process typically moves through concept review, topology and material selection, prototyping, and validation testing against the application's real operating conditions — not just a bench test at room temperature.
Don't underestimate the value of an existing motor as a reference point, even an imperfect one. Mounting dimensions, shaft specifications, and known failure modes from a legacy unit shorten the design cycle considerably.
The best outcomes come from treating the manufacturer as an engineering partner from the first conversation, not a vendor brought in after the specification is already frozen.