Triac motor speed control

Claim 2

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier having its input terminals coupled in series with the main current path of said triac, the series combination of said bridge rectifier and said triac being coupled across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, the series combination thereof being coupled in parallel to said triac, said timing capacitor being also connected between said other terminal of said diac and one main current terminal of said triac; means for coupling a motor armature to the output terminals of said bridge rectifier; a first reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and a second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; and a second reset circuit coupled in parallel to said first reset circuit but with diodes connected in opposite polarity.

Claim 3

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier having its input terminals coupled in series with the main current path of said triac, the series combination of said bridge rectifier and said triac being coupled across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, the series combination thereof being coupled in parallel to said triac, said timing capacitor being also connnected between said other terminal of said diac and one main current terminal of said triac; means for coupling a motor armature to the output terminals of said bridge rectifier; a first reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; a second reset circuit coupled in parallel to said first reset circuit but with the diodes connected in opposite polarity; and a feedback potentiometer connected across the input terminals of said bridge rectifier, said bridge rectifier being coupled to the other main current terminal of said triac and said feedback potentiometer having a movable tap which is connected to one end of said speed potentiometer.

Claim 4

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier having its input terminals coupled in series with the main current path of said triac, the series combination of said bridge rectifier and said triac being coupled across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, the series combination thereof being coupled in parallel to said triac, said timing capacitor being also connnected between said other terminal of said diac and one main current terminal of said triac; means for coupling a motor armature to the output terminals of said bridge rectifier; a first reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; a second reset circuit coupled in parallel to said first reset circuit but with the diodes connected in opposite polarity; and a feedback potentiometer connected across the input terminals of said bridge rectifier, said bridge rectifier being coupled to the other main current terminal of said triac and said feedback potentiometer having a movable tap which is connected to one end of said speed potentiometer.

Claim 5

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier, the input terminals of said bridge rectifier being coupled in a series loop with the main current path of said triac across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, said timing capacitor being connected between the other terminal of said diac and one main current terminal of said triac, said bridge rectifier being also coupled to said one main current terminal of said triac; means for coupling a motor armature to the output terminals of said bridge rectifier; a reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and a second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; a line voltage compensation circuit having a resistor and a back-to-back pair of Zener diodes connected in series, the series combination thereof being coupled in parallel with the main current terminals of said triac, the series combination of said speed potentiometer and said timing capacitor being connected in parallel with said Zener diodes; and a feedback loop connected between said other terminal of said diac and the supply line side of said bridge rectifier.

Claim 6

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier, the input terminals of said bridge rectifier being coupled in a series loop with the main current path of said triac across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, said timing capacitor being connected between the other terminal of said diac and one main current terminal of said triac, said bridge rectifier being also coupled to said one main current terminal of said triac; means for coupling a motor armature to the output terminals of said bridge rectifier; a reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and a second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; a line voltage compensation circuit having a resistor and a back-to-back pair of Zener diodes connected in series, the series combination thereof being coupled in parallel with the main current terminals of said triac, the series combination of said speed potentiometer and said timing capacitor being connected in parallel with said Zener diodes; and a feedback loop connected between said other terminal of said diac and the supply line side of said bridge rectifier.

Claim 7

A motor speed control circuit as claimed in claim 3 wherein said feedback loop includes a fixed resistor, a capacitor in parallel with said fixed resistor, and a variable resistor in series with said fixed resistor.

Claim 8

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier having its input terminals coupled in series with the main current path of said triac, the series combination of said bridge rectifier and said triac being coupled across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, the series combination thereof being coupled in parallel to said triac, said timing capacitor being also connected between the other terminal of said diac and one main current terminal of said triac; said diode bridge rectifier being coupled to the other main current terminal of said triac; a reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and a second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; a motor of a type such that it acts as a generator when current is not being supplied to its armature, the motor armature being coupled to the output terminals of said bridge rectifier; and a feedback potentiometer connected across the input terminals of said bridge rectifier, said feedback potentiometer having a movable tap which is connected to one end of said speed potentiometer; the operation being such that the counter electromotive force generated by said motor when said triac is nonconductive diminished with increasing load on the motor thus tending to stabilize the motor speed.

Claim 9

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier having its input terminals coupled in series with the main current path of said triac, the series combination of said bridge rectifier and said triac being coupled across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, the series combination thereof being coupled in parallel to said triac, said timing capacitor being also connected between the other terminal of said diac and one main current terminal of said triac; said diode bridge rectifier being coupled to the other main current terminal of said triac; a reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and a second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; a motor of a type such that it acts as a generator when current is not being supplied to its armature, the motor armature being coupled to the output terminals of said bridge rectifier; and a feedback potentiometer connected across the input terminals of said bridge rectifier, said feedback potentiometer having a movable tap which is connected to one end of said speed potentiometer; the operation being such that the counter electromotive force generated by said motor when said triac is nonconductive diminished with increasing load on the motor thus tending to stabilize the motor speed.

Claim 10

A motor speed control circuit as claimed in claim 5 which additionally includes a second reset circuit coupled in parallel to said first-named reset circuit but with diodes connected in opposite polarity.

Claim 11

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier having its input terminals coupled in series with the main current path of said triac, the series combination of said bridge rEctifier and said triac being coupled across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, the series combination thereof being coupled in parallel to said triac, said timing capacitor being also connected between the other terminal of said diac and one main current terminal of said triac; a reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and a second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; a motor of a type such that it acts as a generator when current is not being supplied to its armature, the motor armature being coupled to the output terminals of said bridge rectifier; and a feedback loop coupled between said other terminal of said diac and the supply line side of said bridge rectifier; the operation being such that the counter electromotive force generated by said motor when said triac is nonconductive diminishes with increasing load on the motor thus tending to stabilize the motor speed.

Claim 12

A triac motor speed control circuit comprising: a pair of supply line terminals; a triac; a diode bridge rectifier having its input terminals coupled in series with the main current path of said triac, the series combination of said bridge rEctifier and said triac being coupled across said pair of supply line terminals; a diac having one terminal coupled to the control gate of said triac; a speed potentiometer and a timing capacitor coupled together in series, the series combination thereof being coupled in parallel to said triac, said timing capacitor being also connected between the other terminal of said diac and one main current terminal of said triac; a reset circuit including a resistor and a first diode coupled in series with each other and in parallel with the main current path of said triac, and a second diode having one terminal connected to the juncture of said resistor and said first diode in polarity opposite to that of said first diode, and its other terminal connected to the other terminal of said diac; a motor of a type such that it acts as a generator when current is not being supplied to its armature, the motor armature being coupled to the output terminals of said bridge rectifier; and a feedback loop coupled between said other terminal of said diac and the supply line side of said bridge rectifier; the operation being such that the counter electromotive force generated by said motor when said triac is nonconductive diminishes with increasing load on the motor thus tending to stabilize the motor speed.

Claim 13

A motor speed control circuit as claimed in claim 7 wherein said feedback loop includes a fixed resistor, a capacitor in parallel with said fixed resistor, and a variable resistor in series with said fixed resistor; said diode bridge rectifier being coupled to said one main current terminal of said triac;

Claim 14

A motor speed control circuit as claimed in claim 7 wherein said diode bridge rectifier is coupled to the other main current terminal of said triac, and wherein said feedback loop includes a feedback potentiometer connected across the input terminals of said bridge rectifier, said feedback potentiometer having a movable tap which is connected to the resistor end of said speed potentiometer.

Claim 15

A motor speed control circuit as claimed in claim 7 which further includes a line voltage compensation circuit having a resistor and a back-to-back pair of Zener diodes connected in series, the series combination thereof being coupled in parallel with the main current terminals of said triac, the series combination of said speed potentiometer and said timing capacitor being connected in parallel with said Zener diodes.