FEMSAN Launches Serial Production of Slotless BLDC Motors Following a Successful R&D Process

Procurement of slotless BLDC servo motors, which are only manufactured in countries achieving certain technology levels, are becoming achievable from domestic sources. The Defense and Aerospace qualification of slotless BLDC servo motors were launched in 2014 as an R&D project, with all electromagnetic and structural designs were successfully completed by Turkish engineers.

Date: Issue 86 - November 2018

Electric Motors are classified due to many different criteria. One of the most basic qualification methods is that of separating the motor according to the power source that operates the motor. From such a point of view, we come across a grouping of alternative current (AC) and direct current (DC) motors. In addition to this basic classification, electric motors can be categorized as asynchronous - synchronous motors, brush - brushless motors pursuant to the number of phases. The separation within the slotless, BLDC Motor that is the topic of our article is based on the structure of the motor. As it is seen, there are also slotted type brushless motors. Slotless motors are frequently confused with coreless motors. Sometimes, there is a core in the slotted and slotless motors known as lamination. The difference between the two is that while the copper wire winding constituting the electromagnetic area is enrolled within the slot, in the other type the core is in the tubular shape and it externally covers the coils in a cylindrical shape. There are two critical points in slotless BLDC motors. The technological difficulty in the winding is optimizing the magnetic field strength without the tips of the slot, while the difficulty in terms of the process is forming the coils impeccably, and placing them inside the iron core and keeping it there. The slotted  and slotless BLDC motors structures are demonstrated in the image below.

As the name suggests, in the coreless engine structures, there are no cores interacting with the bobbins in any way. The windings are hardened with resin or an epoxy derivative chemical and thus the structure could be kept as rigid.