Ours is 90 Mva electric arc furnace . Recently we are facing furnace tripping consistently due to electrode arm Stool & column high temperatures.
Electrical parameters are all normal including secondary current and voltage. Due to reactance coil in phase 2 electrode ,its temperature is historically high compared to other phases.
We did replace temperature sensors, flow sensors but issue still remains same. Water inlet temp is 39 deg C and outlet from phase 2 reaches to 70 while in normal conditions its hovering around 60. There is no change in electrode regulation parameters.

1.What could be the reasons ?

Looking forward for your kind help.

Thanks
Rajat

 

Which temperature sensors did you replace? The ones on the cooling system or the sensor(s) detecting the column temperatures that are used for alarm/trip detection?

Over time, have dissolved or suspended material in the cooling water coated the surface area,effectively insulating the area that needs cooling so that heat transfer is now insufficient to cool the target object? Have you inspected that area?

 

Rajat...
Can you reveal the name of the Furnace Mfg?
Regards, Phil Corso

 

Rajat...
Can you reveal the name of the Furnace Mfg?
Regards, Phil Corso

Mr. Phil, its fuchs arc furnace

 

Which temperature sensors did you replace? The ones on the cooling system or the sensor(s) detecting the column temperatures that are used for alarm/trip detection?

Over time, have dissolved or suspended material in the cooling water coated the surface area,effectively insulating the area that needs cooling so that heat transfer is now insufficient to cool the target object? Have you inspected that area?

Yes we have replaced the flow switch as well as temperature transmitter in return lines. Flushing of lines has been done too. Is there is a possibility of eddy currents or induction in secondary side??how to control that though all electrical parameters are almost matching. Thanks

 

Sounds like a matter of over driving the electrodes, you'll have to reduce the power being delivered.

 

Rajat...
Welcome to Control.Com!
Please furnish recorded measurements for each phase, i.e., V, A, P, for each Phase!
Phil Corso