Benefits and pitfalls when using permanent magnet motors in spinning applications

For close to half a century, the textile and fiber industries have been using synchronous motors in their spinning applications. These motors have traditionally been of the synchronous reluctance-type due mostly to the cost of their nonexcited competitor: the permanent magnet (PM) motor. The steady decline in the cost of permanent magnets paired with less expensive manufacturing techniques have lowered the price of PM motors drastically. This economic attractiveness coupled with its inherent electrical advantages is making the PM motor the motor of choice in new textile and fiber spinning machine installations. The advantages of PM motors versus their synchronous reluctance counterparts, however, can quickly be negated by not thoroughly understanding the predictability of the PM motor's performance. This paper offers some insights into predicting performance of PM motors so they can be most advantageously applied in new installations.