Pre Test / Post Test: Pengenalan HMI

What is meant by blackout in potline operations?

• Intentional current reduction

• Power outage in the potline

• Delayed alumina supply

• Excess metal in the pot

What should the operator do when there is a power outage?

• Leave the pot immediately

• Restart all machines

• Stop all work except redressing and hopper filling

• Open all pot hoods

What should be done if blackout lasts more than 180 minutes and the pot does not improve?

• Add suction gas

• Continue monitoring

• Proceed with normal operations

• Consider the pot for cut-out

What are common causes of blackout in potline?

• Lack of alumina

• Full bath

• Trouble with power plants or rectifiers

• Damage to the anode cover

What is an early indication of a leaking pot?

• Increased air temperature

• Fe or Si in metal increases without clear reason

• High alumina level

• Anode cannot be lowered

If there is damage to the lower busbar greater than 50%, then...

• Just leave it

• Rotate the pot

• Must be repaired immediately

• Directly cut-out

If blackout lasts between 90-180 minutes, the following actions are taken EXCEPT...

• Monitor pot voltage

• Operate the breaker or perform blade periodically

• Leave the anode pallet in place

• Lower the beam slowly according to instructions

What should be done during an emergency to prevent workplace accidents?

• Leave the pot

• Use complete PPE, stay calm, and follow procedures

• Speed up work

• Ignore procedures

The purpose of lowering the jack during a blackout is to...

• Close the gas

• Increase voltage

• Keep the anode submerged in the bath

• Increase pot temperature

If there are 4 problematic anodes such as RWB, broken, and mix welding, the action taken is...

• Stabilize with high voltage

• Insert PHS and take action

• Add liquid bath

• Drill