On-site calibration of large dynamometers ensures Fanø Kran-Service a minimum of delay and a reduction in time and money spent on transportation.

Denmark's offshore capital, Esbjerg, is the home of the medium-sized company Fanø Kran-Service A/S. The company was founded in 1995 and now employs around 100 employees with broad expertise in performing high quality services in the oil, gas and wind turbine industries and servicing on board installations on ships across the entire world.

Fanø Kran-Service handles the maintenance of various types of complex machinery, including cranes and lifting equipment. The cranes can lift up to 150 tonnes, for example containers, pipes and other heavy items. Safety is therefore paramount to ensure that the cranes are not overloaded. If the crane breaks during operation, it can cause serious material damage and, in the worst case, injury.

Fanø Kran-Service thus carries out an annual inspection of the cranes, including a check of the cranes’ load display system, which shows the crane operator the weight of the load. This ensures that the crane lifts within the permitted weight limit and is not overloaded. The weight is also crucial in calculating the price, e.g. for the transport of goods containers.

Fanø Kran-Service’s staff bring their own calibrated dynamometers to test the crane’s load display system. A dynamometer is an advanced set of weighing scales that is mounted onto the crane’s hook, after which a test weight is hooked securely onto the dynamometer. Fanø Kran-Service uses water bags as test weights. The bags are around 10 metres long and 6 metres in diameter and can hold up to 100 m3 of seawater, the equivalent of 100 tonnes.

It is our task to calibrate the dynamometers from Fanø Kran-Service; in 2015, we calibrated a total of 38. 

We calibrate dynamometers on site and in Brøndby, Copenhagen

In our laboratory in Brøndby, west of Copenhagen, we calibrate dynamometers with a pulling force of up to 50 tonnes. In order to service a growing number of customers with large dynamometers, which have a pulling force of up to 150 tonnes, we invested in a stronger force transducer in 2015. The transducer is the device which we use to calibrate the dynamometer.

When the large dynamometers with a pulling force over 50 tonnes are to be calibrated, we perform the calibration on-site at Fanø Kran-Service. They place a large calibration bench at our disposal, and we bring the rest of the equipment along with our expertise.  It takes app. one full working day to calibrate the large dynamometers.  We can calibrate at least three of the smaller dynamometers in a day.

Because of the on-site calibration of the large dynamometers, we ensure that Fanø Kran-Service is without the dynamometer only on the day of the calibration. Furthermore, this set-up saves Fanø Kran-Service time and money on transporting the dynamometer.

We calibrate the dynamometers in accordance with ISO 7500-1, which gives Fanø Kran-Service and our other customers the peace of mind in knowing the dynamometers comply with both Danish and international safety regulations. According to the standard, the indication on the dynamometer may deviate by up to 2% compared to the one on the force transducer. If the difference exceeds 2%, we adjust the dynamometer, either on customer premises or in our laboratory.

Test of dynamometers at Fanø Kran-Service A / S. Preparation of test setup.
The test set-up being prepared.
The completed test setup incl. Power transducers and dynamometer at Fanø Kran-Service A / S
The completed test set-up. 1). Blue calibration bench 2). Force transducer 3). Dynamometer