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Class Number: 388 Class Title: ELECTRICITY: MOTOR CONTROL SYSTEMS Subclass Subclass Number Title 800 CLOSED LOOP SPEED CONTROL SYSTEM FOR DC MOTOR WITH COMMUTATOR 801 .Field control, or field and armature control, by digital or combined analog and digital circuitry 803 .Field control, or field and armature control, by analog (only) circuitry 804 ..By pulse width or duty cycle modification 805 ..By phase or frequency modification 806 ..By voltage or current modification 807 ...With variable impedance 808 ..By selection of windings 809 .Armature control by digital or combined analog and digital circuitry 811 ..By pulse width or duty cycle modification 812 ..By phase and frequency modification 813 ..By phase modification 814 ..By frequency modification 815 ..By voltage or current modification 816 .Analog armature control 819 ..By pulse width or duty cycle modification 820 ..By phase or frequency modification 821 ..By voltage and current modification 822 ..By voltage modification 823 ..By current modification 824 ..By variable impedance (e.g., potentiometer) 825 OPEN LOOP SPEED CONTROL SYSTEM FOR DC MOTOR WITH COMMUTATOR 826 .Field control, or field and armature control 827 ..With plural selectable speeds (e.g., manual switch) 828 .Armature control by digital or combined analog and digital circuitry 829 ..By pulse width or duty cycle modification 830 .Analog armature control 831 ..By pulse width or duty cycle modification 832 ..By frequency modification 833 ..By voltage or current modification 834 ..By selection of windings 835 ..By control of motor structure 836 ...Position or number of brushes 837 ..By periodic mechanical switch 838 ..With plural selectable speeds (e.g., with manual switch, potentiometer 839 ...By selecting impedance 840 ....Resistive 841 ....Inductive 842 CLOSED LOOP ACCELERATION CONTROL SYSTEM FOR DC MOTOR WITH COMMUTATOR 843 .Field control, or field and armature control 844 .Armature control 847 ..By voltage or current modification 848 OPEN LOOP ACCELERATION CONTROL SYSTEM FOR DC MOTOR WITH COMMUTATOR 849 .Field control, or field and armature control 850 ..By transformer or inductive devicee 851 ..By patterned switch 852 ..By insertion of resistance 853 .Armature control 854 ..By voltage or current modification 855 ..By selectable or variable impedance 856 ...By insertion of resistance or shorting of circuit 857 ....With relay 858 .....Time delay relay 859 ....With patterned switch 860 ...Manual * ****************************** * CROSS-REFERENCE ART COLLECTIONS * ****************************** 900 SPECIFIC SYSTEM OPERATIONAL FEATURE 901 .Sample and hold 902 .Compensation 903 .Protective (e.g., voltage or current limit) 904 .Stored velocity profile 905 .Armature and field windings connected in series (i.e., series motor) 906 .Proportional-integral system 907 SPECIFIC CONTROL CIRCUIT ELEMENT OR DEVICE 907.2 .Bridge circuit 907.5 .Computer or microprocessor 908 .Frequency to voltage converter 909 .Monitoring means 910 .Operational/differential amplifier 911 .Phase locked loop 912 .Pulse or frequency counter 913 .Saturable reactor, space discharge device, or magnetic amplifier 914 ..Thyratron or ignitron 915 .Sawtooth or ramp waveform generator 916 .Threshold circuit 917 .Thyristor or SCR 918 ..Trigger by unijunction transistor 919 ..Triggered by resistor or capacitor 920 ..Chopper 921 .Timer or time delay means 922 .Tuned or resonant circuit 923 SPECIFIC FEEDBACK CONDITION OR DEVICE 924 .Centrifugal device (e.g., governor) 925 ..Including contacts which open and close motor circuit 926 ..Which controls a vacuum tube or solid-state device in motor circuit 927 ..Which varies resistance of motor circuit 928 ..Which controls position of commutator brushes 928.1 .Counter or back EMF (CEMF) 929 .Fluid/granular material flow rate, pressure, or level 930 .Load or torque 931 ..Electric generator or magnet as auxiliary load 932 ..With reverse torque (e.g., braking) 933 .Radiant energy responsive device 934 .Thermal condition 935 SPECIFIC APPLICATION: 936 .Food preparation equipment 937 .Hand tool