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There are two identical separately excited DC motors ( 147KW, 460V, 705A) connected parallely have been coupled with one single load (Winch). The speed control is through Thyristor control using Allen Bradely Digital regulator 1395 in the armature. Field is adjusted and kept at certain value. Since the motors are connected in parallel, same output voltage is applied to both the motors.
Now while running the load at certain speed reference especially at high speed, it is observed that both the motors take different current. The difference of the current is as high as 300 A. Many of the times one goes into generating mode also.
It has been tried to trim the field to make both the motors share equal load, but it did not work.
1. Is there other method to control the load sharing of the two motors ?
2. What should be the maximum allowable load current difference ?
3. Will the difference of the two motors come down with increase of load?
Now while running the load at certain speed reference especially at high speed, it is observed that both the motors take different current. The difference of the current is as high as 300 A. Many of the times one goes into generating mode also.
It has been tried to trim the field to make both the motors share equal load, but it did not work.
1. Is there other method to control the load sharing of the two motors ?
2. What should be the maximum allowable load current difference ?
3. Will the difference of the two motors come down with increase of load?