Modular Cranes Pty Ltd, a Melbourne-based crane manufacturer, were presented with an unusual problem to solve for one of their customers.
Modular’s customer, a heavy truck trailer manufacturer, already had two 22-metre-wide overhead cranes installed in their factory which ran on the same set of rails.
Each of the cranes was rated at 12.5 tonnes and had given reliable service for many years.
They were identical in their specification, and were synchronised with both their slow and fast speeds, as well as the elapsed distance they travelled to slow down and stop.
The customer’s new production process now required that a third crane was included on the same set of rails to move very long, heavy trailers along the factory, with the load shared between two of the cranes at any one time.
The cranes would be actuated simultaneously, as required, using a wireless handheld remote control.
The problems faced by Modular Cranes were that the existing overhead cranes were no longer available to be sourced, and that an alternative needed to be installed and synchronised to match the existing cranes. Importantly, Modular Cranes were looking for a solution that also needed to be economical for their customer.
Modular Cranes sought the expertise of NORD Drivesystems, the German Helical geared motor and frequency inverter manufacturer, for the two travel drive Helical geared brake motors on the new crane.
To solve the synchronisation problem, NORD Drivesystems’ de-centralised frequency inverter technology was also employed.
To further enhance the economy requirement, NORD Drivesytems proposed a conventional 4 pole electric motor with a 10Nm electromagnetic brake mounted to each of the NORDBloc.1 series inline Helical geared brake motors.
The NORD SK205E series de-centralised frequency inverter was also included, complete with internal 24 Volt power supply cartridge, and an external brake resister to accommodate the re-generative current produced by the cranes’ weight when slowing to a stop.
The high-precision accuracy of the NORD Helical gear set and the flexibility of the de-centralised frequency inverter software allowed this new crane to be synchronised with the existing cranes, without the requirement of rotary encoders.
Furthermore, utilising the two de-centralised frequency inverters eliminated the need or any shielded cable in this installation. Modular Cranes commissioned the new crane in 2012 and met their customer’s expectations regarding their requirement for an economic solution.
For all further information regarding NORD Drivesystems products and services, please go to www.nord.com , or phone 1300 – 00 NORD ( NORD ), or email au-sales@nord.com