In the welding and repair plant at the CATERPILLAR service depot in Upplands Väsby, Sweden there is an Electrical Overhead Traveling crane with two hoists, capacity 5 ton and 10 ton respectively. The crane was designed for a load combination of max. 10 ton. The two hoists are used separately or jointly but must never be loaded with more than the sum of 10 ton. Individual overload protection of the two hoists was also required. Furthermore, the customer specified an overload protection system offering separate visual load indications since determining the approximate weight of assemblies would be very useful.
The PIAB LKVE Electronic force transmitter with the PIAB Electronic Unit 8:300 prepared for load indication.
Engson (Sales and Service of CATERPILLAR machinery), Upplands Väsby Sweden.
Engson chose a PIAB System for the following reasons;
- Installation could be made without influencing or changing the design of the traveling crane.
- The simple installation and consequent short down-time as the PIAB equipment is preset from factory. The switch values are already adjusted and test loading is not necessary. The system uses an output (4-20 mA), which is resistant to interference. Therefore standard non-shielded cables can be used. Normally the Overload Protection System cables can be installed together with other electrical cables of the traveling crane without causing any interference problems.
- The PIAB LKVE is protected against faulty operation and indicates an overload condition for all (if there are any) combinations of cable faults and/or short circuits The load cell in the PIAB LKVE can be overloaded mechanically by 100% of the nominal load without affecting the accuracy of measurement.
- The PIAB System does not limit the working range or the working capacity of the crane.
After years of operation they have noted a significant reduction of maintenance cost. As a bonus, overload related standstills or damages have disappeared.