Motion control system helps lighthouse

The motion control system drives 5,000 kg lantern optical system at a constant speed from a 24V battery source. It will be used to provide a long life, low maintenance and cost-effective solution for Mclennan’s unmanned lighthouse on Tory Island, off the north-west coast of County Donegal.

An integrated brushless servo motor with built-in encoder, servo drive and intelligent

motion controller was chosen from Mclennan’s distribution partner JVL Industri Elektronik.

Minimises cabling

A 400 W version with 24 – 48 V DC power and RS 485 communications is part of a range that extends to a wide choice of communications and servo feedback options. This distributed control solution also minimises cabling between the motor control and the control cabinet in the lantern room where space is at a premium.

For the drive mechanics, two low-backlash planetary gearboxes were mechanically coupled as a single rotary servo-actuator to provide the required torque and speed characteristics for the application. With a final output speed of around 14 rpm and the stringent acceleration torque and generous safety margins accounted for, Mclennan selected NP series 015 and 035 gearboxes from its distribution partner WITTENSTEIN alpha.

These high efficiency gear units, with 70mm and 120mm nominal diameters, provided 10:1 and 20:1 ratios respectively, and the two-part assembly was complemented with a servo flange output and a Mclennan-designed shaft adapter for the drive pinion. The free-wheel clutch was also integrated into the assembly.

By Rebecca Jeffrey