Static field current control apparatus for reel drives

Claim 2

In strip handling apparatus including a reel upon which strip material may be wound and unwound, a variable speed d-c motor for driving the reel, the d-c motor having armature and field windings, and motor field current supply means comprising: means for generating a diameter signal directly proportional to the diameter of the strip material wound on the reel, and static circuit means coupled to said diameter signal generation means for receiving said diameter signal therefrom, said static circuit means being responsive to said diameter signal to generate an electric output signal having a magnitude defined by: F D/(A + BD) where F is the magnitude of the output signal, D is the magnitude of the diameter signal, and A and B are constants having magnitudes established in accordance with saturation chracteristics of the d-c motor.

Claim 3

Motor field current supply means as defined by claim 1 in which said static circuit means is coupled to the field windings of the d-c motor for supplying the output signal of said static circuit means to the field windings as the motor field current, said constants A and B having magnitudes established such that the field strength varies linearly with the diameter signal.

Claim 4

Motor field current supply means as defined by claim 2 further comprising means for generating signals proportional to A and B, said static circuit means comprising a plurality of static circuit elements interconnected to operate on the diameter signal and the signals proportional to A and B to produce the output signal.

Claim 5

In strip handling apparatus including a reel upon which strip material may be wound and unwound, a variable speed d-c motor for driving the reel, the d-c motor having armature and field windings, and motor field control means responsive to a reference signal for varying the field current in accordance with variations in the reference signal, reference signal generation means comprising: means for generating a diameter signal directly proportional to the diameter of the strip material wound on the reel, and static circuit means coupled to said diameter signal generation means for receiving said diameter signal therefrom, said static circuit means being responsive to said diameter signal to generate a reference signal having a magnitude defined by: F D/(A + BD) where F is the magnitude of the reference signal, D is the magnitude of the diameter signal, and A and B are constants having magnitudes established in accordance with saturation characteristics of the d-c motor such that the field strength varies linearly with the diameter signal.

Claim 6

In strip handling apparatus including a reel upon which strip material may be wound and unwound, a variable speed d-c motor for driving the reel, the d-c motor having armature and field windings, and motor field control means responsive to a reference signal for varying the field current in accordance with variations in the reference signal, reference signal generation means comprising: means for generating a diameter signal directly proportional to the diameter of the strip material wound on the reel, and static circuit means coupled to said diameter signal generation means for receiving said diameter signal therefrom, said static circuit means being responsive to said diameter signal to generate a reference signal having a magnitude defined by: F D/(A + BD) where F is the magnitude of the reference signal, D is the magnitude of the diameter signal, and A and B are constants having magnitudes established in accordance with saturation characteristics of the d-c motor such that the field strength varies linearly with the diameter signal.

Claim 7

Motor field control means as defined by claim 4 further comprising means for generating signals proportional to A and B, said static circuit means comprising a plurality of static circuit elements interconnected to operate on the diameter signal and the signals proportional to A and B to generate the reference signal.

Claim 8

Motor field control means as defined by claim 4 further comprising means for generating signals proportional to A and B, said static circuit means comprising: first means coupled to said diameter signal generation means to receive the diameter signal therefrom and coupled to receive the signal proportional to B, said first means being responsive to the diameter signal and the signal proportional to B to generate a signal proportional to BD, second means coupled to receive the signal proportional to A and coupled to said first means to receive therefrom the signal proportional to BD, said second means being responsive to the signal proportional to A and the signal proportional to BD to generate a signal proportional to (A + BD), and third means coupled to said diameter signal generation means to receive the diameter signal therefrom and coupled to said second means to receive the signal proportional to (A + BD) therefrom, said third means being responsive to the diameter signal and to the signal proportional to (A + BD) to generate the reference signal.

Claim 9

Motor field control means as defined by claim 6 in which said first means comprises a solid state multiplication element and said third means comprises a solid state division element.

Claim 10

Motor field control means as defined by claim 7 in which said second means comprises a summing amplifier.