Swedes shrink servomotors `by more than two thirds`

A Swedish company has developed a range of servomotors that it claims are a third of the weight and a quarter of the size of conventional machines.

The company, High Density Drives (HDD), says its has been able to shrink its motors by using a new principle for the way that iron and copper are used in the stator. HDD`s managing director, Lennart Stridsberg, says that today`s conventional servomotors use essentially the same servo design as was used for synchronous and asynchronous motors almost a century ago.

The result of the new approach to stator design is that one of HDD`s Stritorque motors with a torque rating of 4.2kg, weighs just 3kg, compared to the 9kg of a typical conventional servomotor. It measures 9cm in all three dimensions, compared to the 12cm by 13cm 20cm dimensions of a typical conventional servomotor.

Stridsberg says that the motors` compact size makes them easier to install and can increase the lifting power in applications such as robots because the robotic arm does not have to lift a heavy motor as well as its payload. The 20-pole motors operate at speeds up to 3,000 rpm and are said to emit less heat than conventional machines.

The motors are fitted with a resolver as standard and can be equipped optionally with high-resolution feedback devices. They support both the SinCos and ENDAT standards.