Abstract: A paint gun cleaner includes a spray unit mounted in an enclosure in spaced relation to an opening in the enclosure through which the paint gun to be cleaned is inserted. A ring shaped spray unit combines a solvent dispenser, which may be either a solvent knife generating a curtain of solvent in the central opening of the spray unit or a plurality of nozzles directing solvent onto the paint gun, with an air knife positioned between the solvent dispenser and the enclosure opening. The air knife directs air flow radially and axially inward to prevent escape of solvent, and to recirculate air mixed with solvent around the sides of the spray unit and through the space between the spray unit and enclosure opening to reduce the amount of ambient air which is drawn into and which must be separated from the solvent and dissolved paint before discharge.

Abstract: A control system for energizing a direct current (DC) motor with alternating current (AC) power includes a first voltage sensor for a peak voltage of AC power; a second voltage sensor for a counter electromotive force (EMF) of the motor; a current sensor for an armature current of the motor; a digital processor having a first current controller responding to sensed armature current and a current reference, a cooperating second current controller responding to sensed peak voltage, sensed counter EMF and the current reference signal, and a gating circuit responding to the controllers; and a thyristor converter circuit sequentially gating portions of half cycles of AC power to the motor in response to firing signals from the gating circuit. The controllers may control a gate angle of the firing signals, the control system may include a third voltage sensor for a terminal voltage of the motor, and the armature current may have discontinuous and continuous waveforms.

Abstract: An impact load controller (28) compensates for the speed drop of a drive motor (12), which speed drop is caused by a load disturbance applied to the drive motor (12). A change in the dynamics of a speed controller (30, 34) in a speed regulator system for a stand in a tandem rolling mill is initiated by detecting a speed error (WE) which is greater than a predetermined speed error value and is removed after the speed error has been reduced to a predetermined value. The controller (28) is a pure rate controller whose input is converted into a rate change in speed error, which is multiplied by a gain factor. The resultant gain value product is initially increased by a predetermined factor to provide a high input signal to the (PI) speed controller (34) of a multi-loop speed regulator system for the drive motor (12), and to precharge a low pass filter.

Abstract: A control system for one or more dc motors in which thyristor power modules selectively gate portions of half cycles of ac voltage to the motor field and armature windings, has digitally implemented parallel inner control loops for the armature which each generate an intermediate control signal to which proportional plus derivative control action has been applied. Logic selects the intermediate control signal which phases back firing pulses for the thyristor power modules the most for application to a common digital integrator which produces a control signal having proportional plus integral control action. The voltage across each of the thyristors is monitored and used to detect continuous and discontinuous current operation for adjusting integrator gain.

Abstract: In a master speed regulator system for a multi-stand rolling mill, a control system and method for switching a pivot stand via a bumpless transfer back and forth from the second stand to the last stand depending on the phases of the mill and while the mill is operating. A microprocessor is used for recalculating the master speed reference B1, the integral values for the master speed reference integral controller, and the outputs for the tension/automatic gauge integral controllers for the new pivot state based on conditions of the previous pivot state.