On the Drilling platform our Draw works is driven by three ABB DC motors, each 750 kW
750 V – 1000 Amps. Each motor is controlled by the armature control system BBC Verithyr SZAD, Type : SZAD 06J1-01 3 x 660 V 1290 Amps.
This system is foreseen of the following control cards :
GU480, GH480, RT480, GT480, XT480, XT481, RT481, IE5A, IE6A, VE6, RE3 and HE11A
The cards are NOT foreseen of any additional auxiliary card.
Each motor can selected as Master whereby the other two motors are the slaves.
The complete system is very reliable.
During logging ( with a self make logging system ) I noticed that the current of the “B“ motor
is always higher than the “C” motor, lowest in current is the “A” motor.
Even by selecting the A, B or C as Master is the measurement the same.
These measurement is confirmed with scoop and are taken on the panel meters of the SCR’s
namely the Armature Current and Voltage.
These panel meters are giving the correct value compared with the Armature voltage measured with a Fluke and voltage measured over the shunt ( current signal 0-60 mV )
Sorry but it was not possible to ad the excel graph.
It seems that with this we facing mechanical problems in the gearbox of the Draw works.
The intension is to make an adjustment on the regulation that the three currents are same and limited to 1000 Amps.
The question is where and how can I make this kind of adjustment ?
In the hope that someone can help me out with this I stay with sincere greetings.
Johan