ok dave the air comporessor is:
L2.4/10 Air screw comporessor we use it in locomotive for braking the system consist of to air comporessor for more informition see zis thread: dc motor starter we discuss zis problem in detail
we have an air comporessor driven by dc series motor direct start the system work and stop many times as the air decrease in the main resirvoir , thus the motor temperature get more hot .
as an electirical engineer i want to protect the motor starting by add soft starter to it
But the male and female screw lubricating oil depend up on the delivered compressed air wich splashing the oil over there
And when i add the starter the speed at starting period is less than 1500rpm and the air decrease the starting period may be afew second
Is this affect on the lubricating of male and female of the comporessor
L2.4/10 air screw comporessor
Driven by dc series motor
I guess i found the source of the problem as there is a leakage in the air system
The motor work, the resirvoir pressure become 900Mpa , and the pressure switch open the circuit
But as there is leakage in the air system , the air in the resirvoir decrease , when the air became 750Mpa the pressure switch close and the motor start again , so this procedure make the motor always works with huge starting current , thus the motor's coils became more hot and burn ,
there is another reason , the two air resirvoirs are standing near front of the system, take into account the air drier system not working, and when you drain them the humidity increase and affect the performance of the motor,
Am i true?
The question now is there any method to monitor the motor's coil temperature?
We have tempratue sensor but it been inserted in side the lubricating oil of the male and female screw not the motor's coils
I see three possible solutions.
Fix the leaks and increase the size of the reservoirs to reduce the number of motor starts.
Fit a dump solenoid valve set to open at 850Mpa and shut at 800Mpa so that the compressor runs continually so it won't pull the starting current.
Fit a NR valve at the reservoir entrance and a dump valve at the compressor discharge start the compressor with the dump valve open and when it is up to speed close the dump.