KR940002920B1 - Instant reversing circuit - Google Patents

Abstract

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Description

Momentary reverse circuit

1 schematically illustrates a known prior art inverted switch arrangement.

2 is a circuit diagram of a circuit constructed in accordance with the present invention.

3 is a pending U.S. patent application (representative reference number) filed in 1986, 7, 14, entitled "Inexpensive, Load and Speed Sensitive Motor Control Start Circuit" by Wrege et al., Which is incorporated herein by reference. C. 6558-5), a waveform diagram showing the operation of the starting circuit of FIG.

FIG. 4 is a circuit diagram partially showing the modified state of FIG. 2 in accordance with pending applications of legs and the like. FIG.

5 is a waveform diagram showing the operation of the instantaneous inversion circuit of FIG. 2 according to the present invention;

* Explanation of symbols for main parts of the drawings

1: Sovereignty 2: Sovereignty

3: main power switch 4: AC power

6 switch 61 cut-out comparator

62 cut-in comparator 63 third comparator

64: fourth comparator 74: power triac

78, 80: Triac terminal 207, 208, 209: Up switch

210, 211, 212: down switch 213: first cantilever contact arm

213, 214a: fixed contact 214: second cantilever contact arm

215: Wiper Actuator

The present invention relates to a system for quickly reversing the rotational direction of a single-cycle AC induction motor. The invention is particularly priced more than pending US patent application Ser. No. 06 / 834,208, filed by Palaniappan, which is hereby incorporated by reference herein, on February 27, 1986, under the name “instantaneous inversion circuit”. This relates to a reduced and partially good improved system.

When quickly reversing a single-phase AC motor, only reversing the voltage polarity applied to the main and auxiliary windings of the motor during operation will not reverse the motor. That is, the voltage applied to the main winding may reverse polarity every half cycle, regardless of whether the polarity is positive during the first or second half cycle, and may be reversed without interaction with the auxiliary winding. none.

One possible way to reverse the motor is to stop the motor and then reactivate the starting winding with the opposite polarity with respect to the main winding or vice versa. This causes the motor to rotate in the opposite direction. This method of stopping the motor before reversal becomes undesirable or unacceptable in many applications such as, for example, an electric hoist motor, where a momentary reversal is required or required while going in a certain direction. .

In other known reversing systems, mechanical centrifugal disconnect switches are used in combination with mechanical reversing switches operated manually by the user. The user-operated reversal switch controls the first set of external switches to apply the first polarity voltage to the starting winding from the AC power source, and the external of the second set to apply the second reverse polarity voltage to the starting winding from the AC power source. Control the switches. In order to connect the starting winding to an AC power source, the centrifugal switch is normally closed upon initial activation of the motor. This centrifugal switch automatically opens when the motor speed is about 80% of synchronous speed, allowing the starting winding to disconnect from the AC power source. The centrifugal switch has two contact pairs, the first pair of contacts for supplying current through the starting winding in one direction when the set of external switches is closed, and the second pair of contacts for the set of external switches associated therewith. To supply current through the starting winding in the opposite direction when they are closed. At initial activation of the motor, the two contact pairs are closed and one set of external switches is closed to supply current in one direction through the starting winding.

When the motor starts to rotate, the wiper actuator is frictiontrionally dragged by the motor rotation to the first position near the first contact pair, starting from the AC power source when the centrifugal actuator is in operation. The wiper actuator opens the first centrifugal switch contact pair to disconnect the winding. During the operation mode, when the operator manually activates the external reversal switch, a different electrical circuit through the closed second centrifugal switch contact pair is applied to apply the reverse torque to the motor as it supplies current through the starting winding in the opposite direction. . When the motor is decelerated, the centrifugal switch is closed to move the wiper actuator axially, closing the first centrifugal switch contact pair in the open circuit. When the motor starts to rotate in the opposite direction, the wiper actuator is friction dragged to a second position adjacent to the second centrifugal switch contact pair. When the motor speed reaches about 80% of the synchronous speed in this direction of rotation, the centrifugal switch opens to move the wiper actuator axially to open the second pair of contacts and disconnect the starting winding with AC power. The cycle can be repeated, with the operator manually operating the external reversal switch to complete the electrical circuit through the first contact pair. This type of switching arrangement is typically known and commercially available as an "iron fireman" array. Another example is General Electric Lever Switch Eggs 98-1, 8422 (General Electric Reverswitch R98-1,8422). This arrangement provides instantaneous reversal (i.e. immediate application of reverse torque) because the wiper actuator has been moved by the rotation of the motor within the operating state to be prepared and in a position suitable for motor reversal. This type of arrangement has proved useful for its intended purpose, but nevertheless has limited lifetime, excessive contact arching due to disordered switching, fatigue, friction, especially dragging, vibration, mounting position, contacts and wipers of the wiper actuator. Problems inherent to mechanical actuation systems, including actuator wear, are affected.

As in the above-described Pallania plate application, the present invention solves the above-mentioned single phase motor instantaneous reversal and other problems, and provides an electronic system for electrically sensing polarity reversal and automatically reconnecting the starting winding to an AC power source. Instantaneous reverse technology is independent of the contact transfer time of the reverse switch. For example, the operator of the hoist may operate from the up state to the down state momentarily without momentarily delaying the reversing switch in the neutral off position before continuing with the inverted direction position. Can be. Within the Pallania plate application and the present invention, polarity inversion is instantaneously detected and recognized by detecting when one of the main winding voltage and the auxiliary winding voltage transitions from the preceding position to the delay position with respect to the other voltage, Between the windings and the auxiliary winding, the reverse polarity is instantaneously reconnected to the AC power source so that the reverse polarity begins to apply reverse toco to the motor to slow and accelerate the motor in the opposite direction of rotation.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Single-phase AC induction motors have a main winding to start the motor, and a starting or auxiliary winding to start the motor, which is activated when starting the motor from a standstill and then at many motor speeds To be disconnected. The electromagnetic fields in the primary and secondary windings are phase shifted by, for example, capacitance, inductance, resistance, etc. to set the starting and operating torque.

1 shows a known capacitor starting motor starting system and includes an inverting circuit. The main winding 1 and the auxiliary winding 2 of the single phase AC induction motor are connected to the AC power source 4 via the main power switch 3. Capacitor 5 provides incidental phase shift to the starting torque. When the motor reaches a predetermined threshold speed, the switch 6 is opened to disconnect the auxiliary winding 2 from the AC power source 4.

Various types of switches 6 and controllers are known. In one arrangement, mechanical switches and centrifugal actuators are mounted on a motor shaft or rotor. At certain critical speeds, the centrifugal weight is displaced radially outward to open the switch. Certain types of mechanical centrifugal switches that can be used in reverse applications are commonly known as "iron fireman" switches such as those used in the hoist industry. Another example of the switch 6 is General Electric River Switch Al98-1, 8422.

FIG. 1 shows the up state of the switch 6 with the external user operated up switches 207, 208 and 209 closed and the external user operated down switches 210, 211 and 212 open. Within this configuration, the same polarity voltage from the power source 4 is applied to the windings 1 and 2, and current flows in the same direction through the windings during each half cycle. The switch 6 is a centrifugal switch that is sensitive to mechanical direction and is closed when the motor is at standstill and during start-up and is open to disconnect the auxiliary winding 2 from the AC power source 4 when the motor reaches a specified speed. do.

The switch 6 includes a first cantilever contact arm 213 which is normally coupled to the fixed contact 213a. The switch 6 includes a second cantilever contact arm 214 that is normally coupled to the fixed contact 214a. In the stationary state and during start-up when the centrifugal switch is closed, the wiper actuator 215 remains unengaged with the contact arms 213 and 214. During start-up when the motor starts to rotate, the wiper actuator 215 is friction dragged to a first position that changes in the direction of rotation, for example clockwise, to a position adjacent to the contact arm 213 within the first degree. When the motor reaches the specified speed and the centrifugal actuator is operated, the wiper actuator 215 is disconnected from the contact 213a to open the contacts 213 and 213a, so as to disconnect the auxiliary winding 2 from the AC power source 4. The wiper actuator 215 is operated such that the wiper actuator 215 moves to hit the contact arm 213. At this time, the motor is in an operating state.

During the above-described operating state, the contacts 214 and 214a are closed but remain in the open circuit because the down switches 210 and 211 are open. If the user manually operates the reverse switch to the down position, the up switches 207, 208 and 209 are opened, and the down switches 210, 211 and 212 are closed. This connects the main and auxiliary windings 1 and 2 to the AC power source 4 in a reverse polarity relationship. For example, during the first half cycle of the AC power source 4, the current flows downward through the main winding 1. In addition, during this first half cycle, current flows downwardly from the AC power source 4 through the closed switch 210, and then upwards through the auxiliary winding 2, the capacitor 5, contacting It flows through the arm 214 and the contact 24a and then downwards through the closed switch 211. Therefore, reverse torque is applied to the motor, and the motor is decelerated at zero speed and then accelerated in the opposite rotational direction. When the motor decelerates below the specified cut-in speed, the centrifugal switch closes, causing the wiper actuator 215 to become uncoupled from the contact arm 213 so that the contacts 213 and 213a are re- To be closed. At this time, the contacts 213 and 213a are in the open circuit because the switches 207 and 208 are open. When the motor starts to rotate in the opposite direction, the wiper actuator 215 friction drags in this direction, for example in the degree of direction within the first figure, to a second position adjacent to the contact arm 214. When the motor reaches the cut-out speed specified in this opposite direction of rotation, the auxiliary winding from the AC power source 4 is impinged upon the contact arm 214 to decouple the wiper actuator 215 from the fixed contact 214a. The centrifugal actuator operates to open the contacts 214 and 214a to disconnect (2) to operate the wiper actuator 215.

2 shows an electronic switch corresponding to a mechanical centrifugal " iron fireman " switch. Figure 2 uses the same reference numerals as Figure 1 for ease of explanation. Within a preferred embodiment, the electronic system of the present invention is within the application of the above-described legs relating to an inexpensive, load and speed sensitive motor control start circuit and start winding disconnect system which detects and compares the relative magnitudes of the main winding voltage and the starting winding voltage. Used with the motor start circuit described.

2 shows a circuit for controlling a disconnection or start switch 6 comprising a start circuit according to the application of the above-described legs, and also shows a momentary reversal circuit according to the invention.

The circuit in FIG. 2 is connected to terminals T1, T2, T3 and T4 corresponding to the same terminals T1, T2, T3 and T4 in the first diagram of the user-operated twin-pole reversal switch as shown. This circuit controls the start switch 6, which consists of a power triac 74, to automatically connect the auxiliary winding 2 to the AC power source 4 and disconnect it to the AC power source 4 during start-up and start-up mode. do. A user-operated inverting switch for reversing the voltage polarity applied to one of the windings with respect to the other winding from the AC power source 4 is shown at 207-212. This circuit electrically senses this polarity reversal in the operating mode and automatically closes the auxiliary winding 2 to the AC power source 4 by closing the switch 6, i.e., biasing the power triac 74 in a conductive state. This is described later.

A main voltage detector circuit comprising a diode 10 is connected across the main winding 1 to sense the magnitude of the AC main winding voltage. The main winding voltage is sensed through rectifying diodes 14 and 10 and resistors 16, 18, 20 and 28, and filtered by capacitors 22 and 24. The voltage at the node 26 is reduced by a parallel combination of resistors on the one side of the node and resistors 28 and series resistors 18 and 20 on the other side of the node. The voltage at the node 30 is the voltage at the node 26 that is smaller than the drop across diode 10. The voltage at the node 32 is the voltage at the node 30 reduced by a voltage divider consisting of resistors 18 and 20. Voltages at the nodes 30 and 32 are derived from the AC line and provide a reference voltage to the cut-out comparator 61 and the cut-in or restart comparator 62, which will be described later. These cut-out and cut-in reference voltages vary with line voltage, thus providing the same compensation and allowing the motor's cut-out speed and cut-in restart speed to be relatively independent of line voltage. The cut-in restart voltage at the node 32 is less than the cut-out voltage at the node 30.

The auxiliary voltage detector circuit including the diode 12 is contacted across the auxiliary winding 2 to sense the magnitude of the AC auxiliary winding voltage. The auxiliary winding voltage is reduced by a voltage divider network consisting of resistors 34 and 36, sensed through half-wave rectifier diode 12 and resistor 38, and filtered by capacitor 40. The auxiliary winding voltage sensed at the node 42 is supplied to the cut-out comparator 61 and the cut-in restart comparator 62 for comparison against each floating main winding AC line reference voltage.

Half-wave rectified DC power supply is provided from the AC power supply through diodes 14 and resistors 44, 46 and 94, clamped by zener diodes 48, and at node 52 to activate the control circuitry. It is filtered by the capacitor 50 to provide a fixed DC reference voltage, in this case 12V, which will be described later.

Schemanske et al., Incorporated herein by reference, are referred to in the pending US Patent Application Nos. 680, 489, filed on December 11, 1984, entitled "Load and Speed Sensitive Motor Start Circuits." The circuit in FIG. 2 uses a quad comparator chip such as the LM339, in which the manufacturer-specific pin number is shown for clarity. The first, second, third and fourth comparators on the chip are shown by reference numerals 61, 62, 63 and 64, respectively. In the application of the present application and the above-described legs and the like, the flip-flop 21 in FIG. 4 of the above-mentioned application of the Schmansk et al. Is removed, and this flip-flop function is a hard wire connection between the comparators. Which is provided later.

The negative input at pin 10 of comparator 61 is used as the reference input and is connected to node 30. The positive input at pin 11 of comparator 61 is a comparison input and is connected to node 42. The auxiliary winding voltage at the node 42 is greater than or equal to the cut-out value selected in relation to the magnitude of the main winding voltage at the node 30 as a function of motor speed whose magnitude corresponds to a predetermined cut-out speed. Increasing, the output of comparator 61 at pin 13 provides a turn-off high signal. The third comparator 63 is a voltage divider consisting of resistors 66 and 118, having a positive input at pin 7 which is used as a reference input and connected via a resistor 66 to a regulated DC power supply at the node 52. Receives a reduced voltage at the reduced divided node 72. Since the negative input at pin 6 of comparator 63 is a comparison input and receives a turn-off high signal from comparator 61 through diode 68, the high signal at pin 6 is a comparator at pin 1. The output of (63) is made low. The comparator 63 compares the output of the comparator 61 with a reference voltage at the node 72 from the DC power supply at the node 52 and the high turn-off signal at pin 6 is at pin 7. A low turn-off signal at pin 1 is output when it rises in a predetermined polarity direction above a predetermined value relative to the reference voltage. The low turn-off signal at pin 1 is fed via a resistor 70 to a fourth comparator 64 at pin 4 which is a negative input and used as a comparison input for the comparator 64. The positive input of the comparator 64 at pin 5 is the reference input and is in contact with pin 7 of the comparator 63 at the common node 72. When output pin 1 of comparator 63 goes low, input pin 4 of comparator 64 goes low as well, and output pin 2 of comparator 64 sends a turn-off signal to switch 6. Since the high state is provided, the auxiliary winding 2 is disconnected from the AC power source 4, which will be described later. Voltage comparator 64 compares the output of comparator 63 at input pin 4 with a reference voltage at pin 5, and a low turn-off signal from comparator 63 is selected relative to the reference voltage at pin 5. Output a high turn-off signal on pin 2 when decreasing below the value in the desired polarity direction.

The switch 6 includes an optically isolated triac driver such as, for example, MOC3023, as known in the art. The switch 6 is adapted to control the conduction of the power triac 74 and the triac 74 in series with the capacitor 5 and the auxiliary winding 2 across the AC power source 4. A gate circuit comprising 76). The triac terminal 78 is connected to one side of the capacitor 5, and the triac terminal 80 is connected to the AC power source 4. If terminal 78 is positive with respect to terminal 80 and triac 76 is in a conducting state, the triac (such as triac) is allowed to flow through triac 74 between terminals 78 and 80. In order to bias the 74 into a conductive state, current flows from the terminal 78 through the limiting resistors 82 and 84 and the triac 76 to the gate 86 of the triac 74. Capacitor 88 and resistor 82 provide a snubber circuit to optical triac driver 76. Resistor 90 provides gate stability. Photoreaction triac 76 is optically connected to LED 92 and is operated by LED 92 to initiate conduction of triac 76 and conduction of triac 74. When output pin 2 of comparator 64 goes low, the circuit through LED 92 and resistor 96 is completed from the regulated DC power supply at node 52, to operate triac 76. Light rays are generated from the LED 92 to the photoreaction triac 76.

The initial setting device is composed of an RC timing circuit including a capacitor 98 and a resistor 100. At the initial turn-on at the close of the switch 3, current flows from the node 52 through the capacitor 98 and the diode 102 to the input pin 4 of the comparator 64, thus comparator at pin 2. Since the output of 64 is turned low to turn on the LEDs 92 and the triacs 76 and 74, the auxiliary winding 2 is connected to the AC power source 4 at the initial activation of the motor. When the motor reaches the cut-out speed, the voltage at node 42 at input pin 11 of comparator 61 is equal to the voltage at node 30 at input pin 10 of compare 61. The rise-off signal is supplied to the input pin 6 of the comparator 63 so that the output of the comparator 61 at pin 13 goes high to the selected cut-out value associated with it. Since the output of comparator 63 is brought low, a low turn-off signal is fed through resistor 70 to input pin 4 of comparator 64 so that the output of comparator 64 at pin 2 is high. The high turn-off signal prevents conduction through the diode 92 and thus turns off the triac 76, which turns off the triac 74, thus removing the auxiliary winding 2 from the AC power source 4. Disconnect it.

3 shows the AC line voltage across the main winding 1 as shown by the node 104 and also shows the auxiliary winding voltage as shown by the node 106. 3 also shows a half-wave rectified AC line cut-out reference voltage filtered at node 30, a half-wave rectified AC line cut-in reference voltage filtered at node 32, and a filtered at node 42. Half-wave rectified auxiliary winding voltage is shown. Upon cut-out, the half-operated rectified auxiliary winding voltage filtered at the node 42 rises to the half-wave rectified AC line cut-out reference voltage filtered at the node 30, as shown at intersection 108. The winding 2 is disconnected from the AC power source 4 as described above. As described above, the magnitudes of the main winding voltage and the auxiliary winding voltage are compared, and the auxiliary winding voltage at the node 42 including components from the rotational induction voltage due to the rotation of the AC power source 4 and the rotor is obtained by The auxiliary winding 2 is disconnected when increasing to a predetermined cut-out value, such as reference 108, with respect to the main winding voltage at the odd 30.

After the auxiliary winding 2 is disconnected from the AC power source 4, the voltage continues to appear across the auxiliary winding 2 due to the rotation of the rotor which induces a voltage in the auxiliary winding 2. The restart or cut-in comparator 62 senses the rotational induced voltage in the auxiliary winding after starting, i.e. after the auxiliary winding 2 has been disconnected from the AC power source 4, during operation of the motor. The cut-in or restart comparator 62 detects a predetermined amount of reduction in the induced auxiliary winding voltage corresponding to the overload condition of the motor, as at the cut-in crossing point 110 (FIG. 3), where the comparator 62 Turning on the switch 6 and reconnecting the auxiliary winding 2 to the AC power source 4 generates the turn-on signal described above at output pin 14 to reactivate the auxiliary winding. The motor will restart automatically without manual intervention. When the motor gains speed, the magnitude of the voltage at the node 42 again increases above the selected cut-out value with respect to the voltage at the node 30, as at the intersection point 112, and the switch 6 ) Is turned off to disconnect the auxiliary winding (2) from the AC power source (4) after an automatic restart. The cut-in speed is slower than the cut-out speed.

The node 32 and the input as a function of the motor speed corresponding to a predetermined cut-in speed is the voltage induced rotationally across the auxiliary winding 2 at the input pin 8 of the node 42 and the comparator 62. When reduced to a predetermined cut-in value relative to the magnitude of the main winding voltage at pin 9, the output of comparator 62 at pin 14 goes high and provides a turn-on signal. This high turn-on signal is supplied via diode 114 to input pin 4 of comparator 64, causing the output of comparator 64 at pin 2 to be low, thus conducting via LED 92. Thus, the triacs 76 and 74 are operated to connect the auxiliary winding 2 to the AC power source 4. In addition, the low state at output pin 2 of comparator 64 is applied to input pin 6 of comparator 63 through resistor 116 to cause output pin 1 to be high, thus flip-flop or latching operation. A high level is applied to input pin 4 of comparator 64 through resistor 70 to complete the < RTI ID = 0.0 > Resistors 120, 122 and 124 provide a pull-up resistor at the output of each comparator.

FIG. 4 shows an application state in a capacitor driven motor in which a run capacitor 130 is connected between the anodes 80 and 106 in series with the auxiliary winding 2. For clarity, FIG. The tiles are given the same reference numbers. Power trial by a pair of photoreaction triacs 76a and 76b triggered in series optically conductive state by respective LEDs 92a and 92b in series between node 52 and resistor 96. A high breakdown voltage capability is provided in the gate circuit of the liquid 74. The capacitor 88 can be removed because there is already a parallel capacitor 130 in the circuit. Resistors 132 and 134 are active and share voltage spikes or transitions to prevent unnecessary dv / dt turn-on.

The circuits described above are similar to the circuits shown in the application of the above-mentioned racks and have been given the same reference numbers for clarity. Capacitors 117 and 119 have been added to better filter the inputs of the respective voltage comparators 63 and 64.

As in the above Pallania plate application, the present invention provides an electronic system that electrically senses polarity reversal by the user inverting the switches 207-212 during the movable mode and provides the auxiliary winding 2 with an AC power source ( Reconnect automatically to 4). The present invention achieves this function in part with satisfactory circuitry and reduced cost. Another desirable feature of the present invention is that it can simply be added to the circuits of the legs and the like described above with a simple connection in applications where instantaneous reversal is required.

Referring to FIG. 2, diode 14, resistors 44, 46 and 94, zener diode 48 and capacitor 50 are described in the power supply described in node 52 for comparators 61-64. And a reference voltage. The node 52 also provides power supply and reference voltages to voltage comparators 221, 222 and 223 that are part of other quad comparator chips, such as the LM 339. Manufacturer-specific pin numbers are shown for clarity. Resistors 226, 228, and 230 are pull-up resistors at the output of each of comparators 221, 222, and 223, and capacitor 232 provides filtering to remove noise. Voltage from node 52 on line 234 is applied to input pin 5 used as reference input of voltage comparator 221 and input pin 6 used as reference input of voltage comparator 222. Reduced by voltage dividers formed by resistors 236 and 238 to provide a reference voltage at node 240.

The main voltage detector circuit is provided by a diode 242 connected to the terminal T2 at the node 104 to sense the voltage across the main winding 1. The main winding voltage is sensed via diode 242 and clamped by resistors 246 and 248. Capacitor 250, along with resistors 246 and 248, form an RC filter to remove transition voltage noise that may appear on the power line at T2. Therefore, half-wave rectified and filtered voltage is provided to the node 244. An auxiliary voltage detector circuit is provided by the diode 254 to sense the voltage across the auxiliary winding 2. Auxiliary winding voltage is sensed through the diode 254 from the node 106 at T4 and reduced at the node 256 by a voltage divider formed by resistors 258 and 260 and filtered out by a capacitor 262. It is clamped by the zener diode 264. Within the described embodiment, such that the comparators 221 and 222 operate within their rated values, the zener diodes 252 and 264 are each of the nodes 244 and 256 and the respective input pins of the comparators 221 and 222, respectively. Limit the voltage at 4 and 7 to a maximum of 9V. Also within the preferred embodiment, the voltage at the DC power supply line 234 is 12V, dividing down to 4V at the node 240 as the reference input to pins 5 and 6 of the comparators 221 and 222, respectively.

The voltage comparator 221 has a reference input at pin 5 from the power supply, a comparison input at pin 4 from the main voltage detector by the diode 242, and node voltage main winding at the node 214. The output voltage responsive to the predetermined polarity and magnitude of the main winding voltage in relation to the reference voltage compared to the reference voltage at 240. Referring to FIG. 5, the timing line T2 represents the voltage waveform at the terminal T2 and the node 104. Line 266 shows the waveform at output pin 2 of comparator 221 on line 266. If the main winding voltage at node 244 drops below 4V at node 240, the output at pin 2 on line 266 is such that the main winding voltage at node 244 is equal to node 240. Transitions to a high state as shown by transition point 268 (FIG. 5) to generate a pulse 270 that persists until it rises above 4V, where output pin 2 on line 266 is zero. It transitions to the low state as shown by transition point 272 at 5 degrees.

Line T4 in FIG. 5 shows auxiliary voltage waveforms at terminal T4 and node 106. At initial turn-on, the auxiliary winding voltage precedes the main winding voltage by about 90 ° as shown by comparing waveforms T2 and T4 within FIG. After starting, the auxiliary winding voltage in the motor's running mode typically precedes the main winding voltage by 90 ° or less, as shown by the broken line, but the leading rate can be 0 ° -90 °. Line 274 in FIG. 5 shows the output waveform from comparator 222 at pin 1 on line 274. If the auxiliary winding voltage at the node 256 rises above 4V at the node 240, the output 1 of the comparator 22 on the line 274 is the auxiliary winding voltage at the node 256 is the node 240 Output of comparator 222 on line 274 because it is high as shown by transition point 276 (FIG. 5) to generate an output pulse 278 that lasts until it drops below 4V. Pin 1 goes low as shown by transition point 280.

The third voltage comparator 223 has a reference input at the negative input pin 8 on the line 266 from the comparator 221 and the differential circuit 282 from the output of the comparator 222 on the line 274. Has a comparison input on pin 9 (+) via. Output pulse 278 on line 274 from comparator 222 is differentiated by capacitor 284 and input of comparator 223 through diode 286 to generate pulse 288 (FIG. 5). Supplied to node 290 at pin 9. Within the described embodiment, the voltage divider formed by the parallel coupling of resistors 292 and 294 generates a pulse 288 (fig. 5) of 2V amplitude at the node 290. The diode 286 prevents the capacitor 284 from discharging through the resistor 294, thus extending the pulse width of the pulse 288 well to 2 msec. The width of the pulse 288 is smaller than the width of the pulse 270. Diode 286 limits the discharge of capacitor 288 to increase the width of differential pulse 288 and prevents negative pulses from appearing at input pin 9 of comparator 223. Resistors 292 and 294 are connected to common feedback line 296 with respect to comparator 222. The other ends of the resistors 292 and 294 are connected to the respective nodes 298 and 290, respectively. Capacitor 284 is charged through resistors 292 and 284 to provide the elongated differential pulses described, but only through resistor 292. Diode 286 blocks the discharge of capacitor 284 through resistor 294.

Line 300 (FIG. 5) Shows the output of comparator 223 at pin 14 on line 300. FIG. As can be seen in the timing diagram, the differential 2V pulse 288 at the node 290 at the comparison input pin 9 of the comparator 223 is a 12V pulse 270 on the line 266 at the input eighth. While the output of comparator 223 at pin 14 on line 300 goes low. This low signal prevents conduction of the diode 302 connected by the line 304 to the node 306 at the input pin 4 of the comparator 64, so that the output of the comparator 64 at pin 2 is high. In this state, the triac 74 remains off and the auxiliary winding 2 is disconnected from the AC power source 4 because the LED 92 is kept in a non-conductive state. The dashed waveform shown by lines T4, 274 and 290 in FIG. 5 shows how the auxiliary winding voltage at T4 is phase shifted in relation to the line voltage at T2 during normal acceleration of the motor at running speed. . During this acceleration, transitioned differential pulse 288a is still generated concurrently with pulse 270 and at line 300 the output of comparator 223 remains low. While the auxiliary winding voltage precedes the line voltage (rotates in either direction), output pin 14 of comparator 223 on line 300 remains low.

When the user operates the inversion switch to open the switches 207-209 and close the switches 210-212, the polarity of the auxiliary winding voltage at terminal T4 is reversed. That is, as shown by the timing line T4-R (FIG. 5), it is shifted by about 180 degrees from the preceding position to the delay position with respect to the main winding voltage. This voltage is induced in the auxiliary winding due to the rotation of the motor, and momentarily phase shifted by about 180 ° when the user activates the reverse switch. Auxiliary winding voltage at input pin 7 of node 256 and comparator 222 rises through zero to reach 4V level at node 240 and input pin 6 at reference 308 (FIG. 5). In this case, the output of the comparator 222 on the line 274 becomes high as shown by the transition point 310 in the timing line 274-R, so as shown on the timing line 274-R. Similarly, the differential pulse 312 is generated. The pulse 312 does not coincide with the pulse 270 on the line 266, but instead occurs when the voltage on the input pin 8 of the line 266 and the comparator 223 is less than or equal to zero, thus the pin on the line 300. The output of comparator 223 at 14 goes high as shown by pulse 314 in timing line 300-R. This high signal is transmitted via diode 302 and line 304 to node 306 at input pin 4 of comparator 64, which drives the output of comparator 64 at pin 2 to a low state, Allows conduction through LED 92 to turn on triac 74 and reconnect auxiliary winding 2 to AC power source 4 to decelerate the motor and cut-out to comparator 61 as described above. Reverse torque is applied to the motor to accelerate the motor in the opposite direction until The node 306 is common with the output of the comparator 62 at pin 14 via diode 114 and the output of comparator 63 at pin 1 via resistor 70.

Typically, the inversion is achieved because the motor decelerates during the first line cycle after the triac 74 becomes conductive and the auxiliary winding voltage at the node 42 is below the level at which normal cut-out occurs. Only a single pulse at the output pin 14 is required for the comparator 223 on the line 300. The motor has not been decelerated sufficiently due to, for example, contact bounce of the reversing switch, and another positive pulse is output on the line 300 from the comparator 223.

Thus, the present invention provides a first voltage detector device configured with a comparator 221 for sensing a primary winding voltage, a second voltage detector device configured with a comparator 222 for sensing an auxiliary winding voltage, and a reference input at line 266. And AC auxiliary windings 2 having a comparison input at the node 290 from each of the first and second voltage sensors and being polarized by the inversion switch 207-212 when operated by the user. Provided is a third voltage detector device consisting of a comparator 223 having an output at line 300 that activates start switch 74 to reconnect to power source 4. The first voltage detector outputs a pulse 270 (FIG. 5) in response to a predetermined polarity and magnitude of the main winding voltage. The second voltage detector outputs a pulse 278 (fig. 5) in response to a predetermined polarity and magnitude of the auxiliary winding voltage induced during the motor's running mode, the induced auxiliary winding voltage being derived from the main winding voltage during the running mode. 0 ° -90 ° phase transition. Differential circuit 282 differentiates the output pulse 278 from the second sensor into a pulse 288 (FIG. 5) with a reduced pulse width narrower than the output pulse 270 from the first sensor. The third sensor in the comparator 223 compares the pulse 270 with the pulse 288.

Upon polarity inversion, the auxiliary winding voltage is shifted about 180 ° with respect to the main winding voltage, and the differential pulse 288 is related to the timing line 290 with respect to the output pulse 270 from the first sensor on the timing line 266. Transition from the movable mode position as shown in FIG. 5) to the polarity inversion position as shown by pulse 312 on timing line 290-R (FIG. 5). Within the movable mode position, the differentiated pulse 288 is generated simultaneously with the output pulse 270. Within the polarity inversion position, the differentiated pulse 312 is not generated simultaneously with the output pulse 270. Comparator 223 responds to the relative transitioned output pulse to actuate start switch 74 to reconnect auxiliary winding 2 to Ac power source 4.

The invention may be modified in various forms within the scope of the appended claims.

Claims (11)

It has a main winding and an auxiliary winding that can be connected to an AC power source, and has a start switch device for automatically connecting the auxiliary winding to the AC power source in the start-up and running modes, and disconnecting from this AC power source and related to the other of the windings. A single phase AC induction motor having a reversible switch operable by a user for reversing the voltage polarity applied to one of the windings from an AC power source, the single phase AC induction motor electrically sensing the polarity reversal during the movable mode and And a device for automatically reconnecting the power supply to the AC power source, wherein the sensing device detects a main winding voltage, a second voltage sensing device sensing a secondary winding voltage, and the first and second voltages. Has a reference input from one of the voltage detector devices and detects the first and second voltage A third comparator device having a comparator input from another voltage sensor device in the device and having an output for operating said start switch device to reconnect said auxiliary winding to said AC power source upon said polarity reversal; A momentary reversal circuit comprising a voltage sensor device. 2. The differentiator device according to claim 1, wherein said differential device is between said second voltage sensor device and said voltage comparator device of said third voltage sensor device and differentiates each one of said reference input and said comparison input to said voltage comparator device. Instantaneous reversal circuit comprising a. 3. The method of claim 2, wherein the differentiator device is adapted to interrupt discharge of a capacitor through a capacitor, a pair of resistors connected in circuit with the capacitor such that the capacitor is charged through two resistors, and one of the resistors. And a diode connected in the circuit with the capacitor. 3. The apparatus of claim 2, wherein the first voltage detector device generates a pulse in response to a given polarity and magnitude of the main winding voltage, wherein the second voltage detector device is between 0 ° and 90 ° from the main winding voltage in the movable mode. Output a pulse in response to a given polarity and magnitude of the auxiliary winding voltage induced during the movable mode phase shifted by °, and the differentiator device differentiates to a reduced fall width that is better than the output pulse from the second voltage sensor device; The differential output pulse from the second voltage sensor device is compared with the output pulse from the first voltage sensor device by the voltage comparator device such that an auxiliary winding voltage at the polarity inversion is related to the main winding voltage. 180 ° transition, and the differentiated pulse is applied in relation to the output pulse from the first voltage sensor device Transition from a mode position to a polarity inversion position, wherein the differentiated pulse is generated simultaneously with the output pulse from the first voltage sensor device at one of the movable mode position and the polarity inversion position, and the differentiated pulse is generated from the movable mode Wherein the output pulse from the first voltage sensor device is not simultaneously generated at a different position between the position and the polarity inversion position. It has a main winding and an auxiliary winding that can be connected to an AC power supply, and has a start switch device for automatically connecting the auxiliary winding to the AC power supply and disconnecting it from the start-up and running modes, A single-phase AC induction motor having a user-operated reversal switch for reversing the voltage polarity applied to one of the windings from an AC power source, the single phase AC induction motor electrically sensing the polarity reversal and operating the auxiliary winding during the movable mode. A device for automatically reconnecting to the AC power source, the sensing device being connected to the AC power source for providing a reference voltage, a main voltage detector device for sensing a main winding voltage, and detecting an auxiliary winding voltage Auxiliary voltage detector device, reference from the power supply device And a comparison input from the main voltage detector device and comparing the main winding voltage with the reference voltage to generate an output pulse in response to a given polarity and magnitude of the main winding voltage in relation to the reference voltage. A first voltage comparator device, having a reference input from the power supply device and having a comparison input from the auxiliary voltage detector device and comparing the auxiliary winding voltage with the reference voltage to the auxiliary winding voltage in relation to the reference voltage; A second voltage comparator device for generating an output pulse in response to the given polarity and magnitude, and a second input having a reference input from the output of the first voltage comparator device and having a comparison input from the output of the second voltage comparator device. Including the three voltage comparator device, One of the voltage and the auxiliary winding voltage is shifted about 180 ° from the preceding position to the delay position with respect to the other winding voltage, and an output pulse from one of the first and second voltage comparator devices And relative to another voltage comparator device of the second voltage comparator device, wherein the relatively transitioned output pulse to operate the start switch device to reconnect the auxiliary winding to the AC power source. In response to the momentary inversion circuit. 6. The apparatus of claim 5, wherein an output pulse from the second voltage comparator device is connected in series between an output of the second voltage comparator device and the comparison input of the third voltage comparator device. And a capacitor that differentiates with a reduced pulse width narrower than the output pulse from the instantaneous inversion circuit. 7. The method of claim 6, wherein the capacitor is connected to the capacitor with force to extend the pulse width of the pulse having a width of the differentiated pulse but less than the width of the output pulse from the first voltage comparator device. And a diode for limiting discharge. 8. The diode of claim 7, wherein the diode is connected in series in the forward direction between the capacitor and the comparison input of the third voltage comparator device, one end of which is connected to the node between the capacitor and the diode anode and the other end of which is A first resistor connected to a common quench line associated with the second voltage comparator device, one end of which is connected to a node between the cathode of the diode and the comparison input of the third voltage comparator device and the other end of the Including a second resistor connected to the common feedback line, the capacitor is discharged through two resistors to provide the extended differential pulse, but not through the second resistor, and the diode is connected to the first resistor. 2. The instantaneous inversion circuit, characterized in that the discharge of the capacitor through the resistor is interrupted. It has a main winding and an auxiliary winding that can be connected to an AC power supply, and has a start switch device for automatically connecting the auxiliary winding to the AC power supply and disconnecting it from the start-up and running modes, In a single-phase AC induction motor having a user-operated reversing switch for reversing the voltage polarity applied to one winding of the windings from an AC power source, the control circuit includes a main voltage detector for sensing the magnitude of the main winding voltage. In response to the device, the auxiliary voltage detector device for sensing the magnitude of the auxiliary winding voltage, the main voltage detector device and the auxiliary voltage detector device, compare the magnitude of the auxiliary winding voltage with the magnitude of the main winding voltage and give the magnitude of the auxiliary winding voltage The magnitude of the main winding voltage as a function of motor speed corresponding to cut-out speed Compare the magnitude of the auxiliary winding voltage with the magnitude of the main winding voltage in response to the first voltage comparator, the main voltage detector device and the auxiliary voltage detector device to output a turn-off signal when increased to a predetermined cut-out value. Stall or overload conditions derived from a voltage induced rotationally in the auxiliary winding during start-up of the motor as a function of the motor speed corresponding to a given cut-in speed where the magnitude of the auxiliary winding voltage is slower than the given cut-out speed A second voltage comparator for outputting a turn-on signal when the voltage is increased to the predetermined cut-in value in relation to the magnitude of the main winding voltage, which is a voltage; a turn-off signal in response to a turn-off signal from the first voltage comparator A third voltage comparator responsive to the output of the first voltage comparator and an output of the third voltage comparator Responsive to a turn-off signal from the third voltage comparator to output a turn-off signal to a start switch to disconnect the auxiliary winding from the AC power source in response to an output of a comparator and direct the auxiliary winding to the AC power source. A fourth voltage comparator responsive to a turn-on signal from said second voltage comparator for outputting a turn-on signal to said start switch for connection, a rectified voltage connected to said AC power source as a power source for each of said comparators And a power supply providing a reference voltage, a second main voltage detector device for sensing a main winding voltage, a second auxiliary voltage detector device for sensing a secondary winding voltage, and a reference input from the power supply device; Has a comparison input from the second main voltage detector device and compares the main winding voltage with the reference voltage A fifth voltage comparator for generating an output pulse in response to a given polarity and magnitude of said main winding voltage in relation to said reference voltage, having a reference input from said power supply device and from said second auxiliary voltage detector magnetic device. A sixth voltage comparator having a comparison input and generating an output pulse in response to a given polarity and magnitude of the auxiliary winding voltage in relation to the reference voltage by comparing the auxiliary winding voltage with the reference voltage. And a seventh voltage comparator having a reference input from the output and a comparison input from the output of the sixth voltage comparator, wherein one of the main winding voltage and the auxiliary winding voltage is different from the winding voltage at the time of the polarity inversion. In relation to the fifth and sixth voltage ratios Output pulses from one of the voltage comparators is transferred in relation to the other voltage comparators of the fifth and sixth voltage comparators and the seventh voltage comparator operates the start switch to reconnect the auxiliary winding to the AC power source. Responsive to said relatively transitioned output pulse. 10. The turn from the first voltage comparator of claim 9, wherein the third voltage comparator compares the output of the first voltage comparator with the reference voltage and rises in a given polarity direction with a value selected in relation to the reference voltage. Outputs a turn-off signal in response to a -off signal, an output of the second voltage comparator and an output of the third voltage comparator are connected together to a common node, and the fourth voltage comparator is connected to a voltage at the common node. Is compared with a reference voltage and outputs the turn-off signal to the start-up switch device when the voltage at the common node is reduced in a given polarity direction with a turn-off value selected with respect to the reference voltage. The turn-on value to the start switch when the voltage at the anode increases in a given polarity direction to a turn-on value selected in relation to the reference voltage. Outputting the turn-on signal to the start switch when increasing in a given polarity direction, and an output of the fourth voltage comparator is applied to an input of the third voltage comparator in response to the output of the first voltage comparator Turn-on applied to the input of the fourth voltage comparator receiving the output of the second voltage comparator so that the fourth voltage comparator continues to generate a turn-on signal from the output of the fourth voltage comparator A turn-on signal from the fourth voltage comparator is applied to a third voltage comparator to output a signal, and the third voltage comparator receives an output of the second voltage comparator to provide a latching flip-flop function. Outputs a turn-off signal to an input of the four-voltage comparator, and turns-off from the output of the fourth voltage comparator such that the fourth voltage comparator continues to generate a turn-up signal. A signal is applied to an input of a third voltage comparator receiving an output of the first voltage comparator, and the output of the seventh voltage comparator is configured to output the output of the second voltage comparator and the output of the third voltage comparator to the fourth voltage. And a common node connected to an input of a comparator. 11. The apparatus of claim 10, wherein the second main voltage detector device comprises a diode and a voltage divider network connected across the main winding, and the second auxiliary voltage detector device includes a voltage divider network connected across the diode and the auxiliary winding. Each of the fifth and sixth voltage comparators has a plus and a minus input, the plus input of the fifth voltage comparator is a reference input and is connected to the power supply device to receive the reference voltage; The negative input of the voltage comparator is a reference input and is connected to the power supply device to receive the reference voltage, the negative input of the fifth voltage comparator is a comparison input and is connected to the voltage divider network of the second main voltage detector device, The positive input of the sixth voltage comparator is a comparison input and the minutes of the second auxiliary voltage detector device Time reversal circuit, characterized in that connected to the network group.

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