Araya’s World

One of the most important applications of linear stepper and synchronous motors is their use in controlling valves. The new Saia EGD Series demonstrates that linear stepper functionality can be used with great value in the gas valve industry.

The seal between the mechanical system for producing linear motion and the current carrying coils of the linear motor is achieved via a stainless steel shaft. This type of drive enables direct linear movement of the valve balls in the gas without imposing mechanics. To achieve maximum possible energy efficiency, the drive is controlled so that it only absorbs power when moving and the adjusting rod maintains its instantaneous position automatically. The fine stepped resolution of > 600 steps over the whole range ensures high control accuracy. The drive is extremely compact with a stator diameter of only 28 mm, and with 500,000 cycles of operation, both life and reliability are achieved.

There are two types of EGD motors available; the EGD 403 gas tight linear motor with push pull movement and the EGD 421 which also incorporates a safety function by means of an integral return spring in the event of supply failure. These motors are ideal for use in boilers, heaters and other gas valve applications.