“Technical consulting provided by Emerson CT is their best selling point,” said John Costanza, president of JC's MarineOilfieldServices. “Their technicians can solve problems quickly and comprehensively, which is very important for things like our business, and indeed It's better than our experience elsewhere. We only use Emerson CT drives in our projects, from 75 to 750 kW, AC and DC."
There are currently approximately 1,600 LeTourneau cranes serving on oil and gas rigs around the world. Although they were originally equipped with large motor generator sets, they did not provide variable speed, which meant that the weight reduction was entirely dependent on the technology of the cantilever operator.
"By changing the cantilever to the Emerson CT variable speed drive, we can ensure complete control of the speed and speed of the cantilever movement, so loads of up to 50 tons can be dropped to the ground like 'feather-like' rather than 'slamming'." Mr. Costanza said.
The cantilever motor drive system includes a SP5402 Unidrive variable speed AC drive rated at 210A continuous current, while the hook motor drive system uses a MentorMP420A4R DC drive rated at 420A continuous current. A Mentor MP210A4R rated at 210A continuous current is assembled to the rotary motor drive system. All drives are deliberately selected at twice the normal power required, which means the system never runs at its maximum capacity.
“I have been working with the new system for 12 months and have not encountered a problem,” said Justin Hillard, LeTourneau crane operator at the Atlantic 7 rig. “These controls are very user friendly, very smooth, and hooked. There is a wide variable speed on the swivel and boom. In my opinion, the boom is the biggest operational improvement. With its variable speed, you can carefully move the boom into position and keep the load stable and on the deck. The safety of personnel."
Justin also praised the enhanced security provided by the new system: "This crane is much quieter without the motor generator set running - you can hear what the crane is doing and what is happening around you. I also noticed that if you are in a position where you can't see the hook, you can actually hear the sound of the hook motor running and know how fast the hook is driving. I highly recommend this system - it is even more Safe, smooth and quiet, and requires little maintenance."
David Powers, consultant consultant for LeTourneau cranes at the Atlantic 7 rig, also likes the new control system. He has a design consistency certificate from the US Department of Shipping (ABS). “This new system provides better working parameters for cranes and is more responsive, and most importantly, these changes enable a safer working environment,” he said.
“Brake is achieved automatically, which increases safety and eliminates the operator's responsibility,” adds Mr. Costanza. “In addition, reliability is improved because the load is not suddenly “taken away”.”
Emerson CT's AC and DC driver technology brings additional benefits to end users, including conformal coatings on PCBs, which help protect the marine environment while providing a wide operating temperature range.