Hi guys.. I am new to this forum.. I was observing some of the discussions here and I've seen a lot of professional electrical practitioners here.. By the way, I am an industrial electrician on one of the biggest petrochemical company here in KSA.. I only hold a working contract here because I am a Filipino..
We have an expansion on our plant..I want to know your expert opinion guys about this Liquid rotor starter (Water with sodium carbonate) which is recently installed on our 13.8 KV, 8 MW motor.. I know some of you guys already experienced this kind of set-up but since this kind of starter is new to me then I want to have an input about the advantages and disadvantages of this kind of starter..
Here’s the motor specs which having a liquid rotor starter:
KW = 8000 Rev / min = 1193 St. Volts = 13200 ± 5% St. Amps = 394 Rotor Volts = 2778 Rot amps = 1727 Freq. = 60 Hz Ph. = 3 Enclosure = IP55 Stator mass = 19000 kg Rotor mass = 11600 kg Cooler mass = 3400 kg Rotor axial float = 12 mm total Oil qty. / bearing = 34 liters / bearing Oil flow / bearing = 9 liters/min/bearing Water flow bundle = 396 liters / min
Our ambient temperature here reaches 56 degrees Celsius during summer and the motor application is for Polymer Extruder.. And also, There's no capacitor bank installed on this motor when I checked the drawing..
Yes sparkyinak it's a big motor, We have 2 existing plants having 2 Extruder motors each. our plant 1 and 2 is having 5 MW motor but not same set-up as what we installed now.. actually, we solo run the motor today and there's no voltage drop.. We have possitive impact on it's first run but we'll see the performance after the screw conveyor is coupled..
I don't know where to host my pdf file for the motor design.. I will re-upload this file for some other time.. Download it here.. sorry for inconvenience.. thanks
@JValdes Yes JValdes all the above data's is in the drawing I've uploaded on my previous reply.. it was made by ABB automation.. I think that was Germany.. the motor manufacturer performance actually is already proven on its all outputs in the years of service.. and 90 % of our plant uses ABB motors and some are SEW eurodrive for product handling / packaging mostly.. I was only looking for any idea about this electrolyte rotor starter.. anyway, the board of our inspectors already approved the said starter just today after they successfully run this motor with load.. thank you for the reply.. I appreciate you guys for being so attentive on our concerns..
@resqcapt19 thank you resqcapt19 I will try this link.. more power to this forum..
Dennis, I take it that the 'starter' has plate[s] which can be dipped progressively into a bath of electrolyte, [such as a salt solution], varying the area wetted to give variable resistance and thus controlled amps for starting. This method has been in use since the 1920s.
That's correct Alan Belson, We installed this starter to control the torque and speed of the motor during start-up by varying the resistance in the rotor. We used this to have a soft start and to help our pony motor during its initial start to have a soft slope of current and avoid excessive stress on the rotor winding. On its final run when the speed is already at its maximum, this starter will cut-off and the short circuit mechanism on the motor rotor will be engaged. Is anyone here have an idea what will be the future problem of having this starter? considering that we have 2KV voltage being dipped on it.. anyway, thank you so much Alan Belson.. I'll be temporarily out for some time.. I'll be back soon.. Thank you..