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At the ZEDCON Manufacturing Plant nothing goes to waste. The main arc furnace is the largest arc furnace in the world, by a large margin. It is used to melt down scrap steel from the stamping processes to be reused.
It is a DC furnace, and has two operators. One human working 12 hour days, and one mech, working 18 hour days. Their shifts overlap twice for 3 hours.

Normally furnace operation is smooth, but that doesn't mean this panel hasn't seen some action.

Just for fun, I will try to explain some of the controls. In general from left to right. The 3 large gauges indicate the incoming AC supply voltage to the rectifier rooms. It is measures after the huge step down transformers, so it ends up being around 13kV RMS. This information is important, because depending on rectifier settings, you can introduce huge voltage sags on individual phases of the 13kV. Obviously you want to try and balance these voltages.

The panel below that reads "PUSH WITH FORCE TO INTERRUPT" is like an emergency stop. Grabbing the handle and pushing it into the panel will kill a safety circuit, cutting the AC supply. You would really not want to do this with the electrodes down, as they will become stuck (molten material will collapse onto the electrode). This would be a huge problem that would be costly and time consuming to repair. This would be considered only if much greater damage was imminent, or there was a immediate threat to human life.

To the right of this is the rectifier control panel. Each phase has a high power variable transformer and up to 9 rectifiers. Each with it's own capacitor bank. The variable transformers step down and regulate the AC voltage to the rectifiers. This is how the DC voltage is controlled. Range is approx 50 - 1000 VDC. The round gauges measuring the AC Voltage from the variable transformers. The selector switch can put the rectifier control from Auto to Manual. The square gauge reads bank current. This can be thousands of amps on the low voltage side. The 9 button panel allows you to manually drop out rectifiers. The buttons are illuminated and show red or yellow to indicate problems. Green is OK.

Directly above this is an oscilloscope. It displays the waveforms from the 13Kv supply. The arc furnace tends to introduce large voltage fluctuations and noise. These should be suppressed and not impact the supply, but if there is a capacitor problem or some crazy arcing in the furnace, it can be seen on this display.

To the left is the horn button. It sounds a loud air horn in the furnace chamber. The operator will sound the horn several times before energizing the furnace. It is also used to get the attention of other personnel in the furnace chamber.

Above it on top of the panel is a CCTV system that is used to monitor the furnace. The middle section of the panel are the furnace controls. The big lever on the left is used to set the electrode depth. Normally automatically controlled by the system. The lever has hydraulic feedback, which allows the operator greater control of the electrode. If the electrode experiences resistance to descending. the operator can feel that in the controls. If the electrode is stuck, the controls will be extremely stiff. The large linear gauge above it reads the current electrode depth. The 3 rectangular indicators above indicate if the electrode is fully extended, or retracted. The top one indicates an electrode motion alarm. The large selector switch switches the controls to manual (levers). This gives full control of electrode depth and DC voltage to the operator. There is a sticky note which reads "CALL ME BEFORE TURNING LEVER x65988". The right lever sets the electrode voltage. Electrode voltage is displayed on the large gauge above. This lever also has feedback. Resistance to voltage change can be felt when moving the lever. The gauge cluster in the center indicates hydraulic pressures for the electrode mechanics as well as coolant and oil temps. The small switches set different things such as the lid locks, lid lift, bypass coolant, and backup oil pumps.

Next item to the left are the coolant tank levels. Above that is the phone. It is just like any other phone in the plant, and can send and receive calls normally. There is a plague that reads "DIAL 100 FOR EMERGENCY". Extension 100 is the emergency line. Above the phone there is a microphone that is used for the external loudspeakers. The mech operator is known to play loud music into the furnace chamber. The large screen is a general display of machine health and operation. Any alarms will readout on this display. On the wall there is an alarm bell. It sounds for severe faults that require immediate operator intervention. Next to it is the EVAC lever. Pulling it down puts the system in evacuation mode. It sounds a bunch of alarms and requires the furnace chamber be evacuated. It would be used in a dangerous emergency, like a failing furnace wall. This does not stop the furnace, allowing the operator to attempt to safely control the situation. Above that is a set of indicators that illuminate if the furnace electrode is energized or not.(edited)

I probably missed some stuff, but that is the gist.

Description
Download for Details!

At the ZEDCON Manufacturing Plant nothing goes to waste. The main arc furnace is the largest arc furnace in the world, by a large margin. It is used to melt down scrap steel from the stamping processes to be reused.
It is a DC furnace, and has two operators. One human working 12 hour days, and one mech, working 18 hour days. Their shifts overlap twice for 3 hours.

Normally furnace operation is smooth, but that doesn't mean this panel hasn't seen some action.

Just for fun, I will try to explain some of the controls. In general from left to right. The 3 large gauges indicate the incoming AC supply voltage to the rectifier rooms. It is measures after the huge step down transformers, so it ends up being around 13kV RMS. This information is important, because depending on rectifier settings, you can introduce huge voltage sags on individual phases of the 13kV. Obviously you want to try and balance these voltages.

The panel below that reads "PUSH WITH FORCE TO INTERRUPT" is like an emergency stop. Grabbing the handle and pushing it into the panel will kill a safety circuit, cutting the AC supply. You would really not want to do this with the electrodes down, as they will become stuck (molten material will collapse onto the electrode). This would be a huge problem that would be costly and time consuming to repair. This would be considered only if much greater damage was imminent, or there was a immediate threat to human life.

To the right of this is the rectifier control panel. Each phase has a high power variable transformer and up to 9 rectifiers. Each with it's own capacitor bank. The variable transformers step down and regulate the AC voltage to the rectifiers. This is how the DC voltage is controlled. Range is approx 50 - 1000 VDC. The round gauges measuring the AC Voltage from the variable transformers. The selector switch can put the rectifier control from Auto to Manual. The square gauge reads bank current. This can be thousands of amps on the low voltage side. The 9 button panel allows you to manually drop out rectifiers. The buttons are illuminated and show red or yellow to indicate problems. Green is OK.

Directly above this is an oscilloscope. It displays the waveforms from the 13Kv supply. The arc furnace tends to introduce large voltage fluctuations and noise. These should be suppressed and not impact the supply, but if there is a capacitor problem or some crazy arcing in the furnace, it can be seen on this display.

To the left is the horn button. It sounds a loud air horn in the furnace chamber. The operator will sound the horn several times before energizing the furnace. It is also used to get the attention of other personnel in the furnace chamber.

Above it on top of the panel is a CCTV system that is used to monitor the furnace. The middle section of the panel are the furnace controls. The big lever on the left is used to set the electrode depth. Normally automatically controlled by the system. The lever has hydraulic feedback, which allows the operator greater control of the electrode. If the electrode experiences resistance to descending. the operator can feel that in the controls. If the electrode is stuck, the controls will be extremely stiff. The large linear gauge above it reads the current electrode depth. The 3 rectangular indicators above indicate if the electrode is fully extended, or retracted. The top one indicates an electrode motion alarm. The large selector switch switches the controls to manual (levers). This gives full control of electrode depth and DC voltage to the operator. There is a sticky note which reads "CALL ME BEFORE TURNING LEVER x65988". The right lever sets the electrode voltage. Electrode voltage is displayed on the large gauge above. This lever also has feedback. Resistance to voltage change can be felt when moving the lever. The gauge cluster in the center indicates hydraulic pressures for the electrode mechanics as well as coolant and oil temps. The small switches set different things such as the lid locks, lid lift, bypass coolant, and backup oil pumps.

Next item to the left are the coolant tank levels. Above that is the phone. It is just like any other phone in the plant, and can send and receive calls normally. There is a plague that reads "DIAL 100 FOR EMERGENCY". Extension 100 is the emergency line. Above the phone there is a microphone that is used for the external loudspeakers. The mech operator is known to play loud music into the furnace chamber. The large screen is a general display of machine health and operation. Any alarms will readout on this display. On the wall there is an alarm bell. It sounds for severe faults that require immediate operator intervention. Next to it is the EVAC lever. Pulling it down puts the system in evacuation mode. It sounds a bunch of alarms and requires the furnace chamber be evacuated. It would be used in a dangerous emergency, like a failing furnace wall. This does not stop the furnace, allowing the operator to attempt to safely control the situation. Above that is a set of indicators that illuminate if the furnace electrode is energized or not.(edited)

I probably missed some stuff, but that is the gist.