JPS588881A - Valve operating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to valve actuation devices and, more particularly, to the control aspects of such valve actuation devices.

More specifically, the present invention is capable of producing a valve operating torque of typically 6 kg/kg at the lower end of its operating range, and up to 1,000 lb/kg at the higher end of its operating range. It is possible to generate a valve operating torque of the order of #-11. This invention relates to a comparatively large-sized valve operating device. Such valve actuation devices have wide application in, for example, thermal power generation, gas storage and oil storage industries, etc.
It also has special uses such as for ships and water gates.

When such actuators are used, the designed operating speed and torque requirements of the actuators, as well as their auxiliary controls, are of critical importance to ensure safe and reliable operation. It is.

Such valve actuators have, for example, an output shaft driven by an electric motor through a gearing arrangement such as a worm and a worm gear, the electric motor being coupled in a dynamic relationship to the output shaft. The output shaft can also be rotated in the direction of inclination in order to open or close the valve. The opening and closing of the valve, ie activation of the motor in either direction, may be activated by a switch, such as a push button.

This motor shutdown is under the control of the R open and J closed run and torque limit switches.

The actuation of these switches to initiate the opening and closing of the valves is
The present invention is limited to providing appropriate energization of a motor start-up circuit, such as a reversing contactor or equivalent static switch element, if the motor begins to rotate in the desired direction. However, it relates to actuating devices in which the activation circuit is integrated with the actuating device, i.e. it is arranged inside the housing of the actuating device. Depending on the type of tomb in which the actuating device is used, the 71 Uzing is either flame-resistant or liquid-tight.

The reversible motor usually consists of a three-phase rust conduction motor. In the case of a three-phase induction motor, the direction of rotation of the motor is determined by the phase rotation of the power supply relative to the motor. If the power supply lead to the actuator is incorrectly connected, the phase rotation of the power supply will not be in the selected direction. This can have serious consequences. For example, [When the Close J button is pressed, the motor rotates in the direction of opening the valve, and vice versa.Furthermore, the travel limit switch and torque limit switch are activated in the direction in which normal travel is selected. The limit switch circuit only stops the motor when the motor is rotating to drive the actuator in one direction. Therefore, these switches cannot protect the actuating device.

British Patent No. 1,144,188 discloses that the integrated motor starting circuit includes a control system for preventing a polyphase motor from starting if the phase rotation of the power source is in the wrong direction. A valve actuation device is described that includes a circuit. A visual alarm will also be issued if the power source is incorrectly connected and an attempt is made to start the motor.

The disadvantage of this control circuit is that if an incorrect connection is made, a skilled technician must be brought in to correct the error. Correcting this error can be very expensive and time consuming since the actuator will not work until the error is corrected.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control circuit arranged so that a reversible polyphase motor always operates in a selected direction, regardless of the direction of phase rotation of the input power supply at the long terminal of the actuating device. be.

According to the present invention, the present invention has a reversible multi-phase motor, and includes a terminal mechanism for connecting to a multi-phase power source, and a mechanism for coupling the terminal mechanism to the motor so that the direction of phase rotation of the power source at the motor terminal can be reversed. , so that the rotation direction of the motor can be selected.
and a control mechanism capable of acting on the coupling mechanism in order to detect the phase sequence of the power source, and the direction of phase rotation at the motor terminal is selected regardless of the direction of phase rotation at the terminal mechanism. A control circuit is provided which is operative to cause rotation of the motor in either direction.

The coupling mechanism consists of a contactor mechanism in the feed line between the terminal mechanism and the motor terminal, the energization of which is selectively K IIJ Ill.

In another embodiment, the coupling mechanism comprises a contactor mechanism and a switching relay connected in a feed line between the terminal mechanism and the motor terminal, the energization of the relay coil being selectively controlled. and a time delay circuit is provided to delay energization of the contactor mechanism relative to the switching relay.

The control circuit detects the phase order in the terminal mechanism, and generates a first output signal when the phase order of the power supply is in a first direction, and generates a second output signal when the phase order is in the opposite direction. the first and second output signals are such that the phase connection at the front distribution motor terminal when the first output signal is present is the same as when the second output signal is present; It works in the opposite way. The phase discrimination circuit includes an optical isolator circuit from which the first and second output signals are extracted from the photodetector.

The invention will now be described in detail, by way of example only, with particular reference to the accompanying drawings, in which: FIG.

The drawings are simplified and do not show, for example, the control circuitry associated with maintaining the contactor in a desired state until a valve travel limit switch or torque limit switch is actuated.

Now, referring to Figure 1, the three-phase power supply circuit has terminals connected to the three-phase power supply during use, "Ll", "L2", "L".
3, and control power terminals 2 labeled rLJ and rNJ.

The control power supply may be independent of the three-phase main power supply, or
The next winding may be obtained from a filter-phase raw power source using a step-down transformer connected to two of the phases of a three-phase power source.

This power supply is applied to terminals TI, T2 and T3 of the polyphase induction motor through a pair of reversing contactors of standard design. - one set of contactors 4 is arranged to couple three phases directly to the motor, the other set 5 is arranged to reverse two of these six phases in a known manner as shown; . Six signal conductors extend from the power supply feed line to a phase discrimination circuit, shown as block 7. The circuit in the block consists of a resistor-capacitive network, arranged in such a way that when the phase rotation of the power supply is in one direction, a control current appears in the line 8 leading to the coil of the control switching relay 9. If in the other direction, line 8
No current flows and the relay coil 9 remains deenergized as shown in FIG. A palanquin phase discriminator path is described in British Patent No. 1.144.188.

The open and close buttons 10 and 11 are such that when the control switching relay 9 is deenergized, the open button 10 acts on the coil 22 and the close button 11 acts on the coil 21, so that the relay 9
This circuit is connected to the contactor, ivy coil 21, and contactor coil 22 via the control changeover relay contacts so that the relationship is reversed when the valve actuator is energized. It operates in the j direction as follows.

For the "valve closing" operation, the electric motor 3 is required to rotate in a clockwise direction, and this rotation direction is
．． The phases in L2 and L3 are in clockwise order and the required connections are Ll to T1, L2 to T2, L3
Let us assume that by connecting T3 to T3 we obtain at a certain time. In this state, the phase discrimination circuit is not sending current to the control switching relay 9 through line 8, so that when the "close" button 11 is pressed, the coil 21 of the contactor 4 is energized, thereby reducing Ll to T1. Connect L2 to T2, then connect L3 for 5 km.

If two of the power supply conductors are reversed at terminal 1, the input power phase will be in the counterclockwise direction.

This causes the phase discriminator 7 to energize the coil of the control switching relay 9, so that when the "close" button 11 is pressed, the coil of the contactor 5 is energized, rather than the previously mentioned coil 21. 22 is energized. Since contactor set 5 reverses the phase rotation, the motor connection is now L1 to T.
2, L2 to T1, and L3 to T3.

Since the input mains conductors have been reversed, the motor will now rotate in the desired clockwise direction. Similar explanations apply for the "valve open" operation.

As previously mentioned, the various limit setting and monitoring components of the control circuit are not shown since they do not affect the operation of the circuit described herein.

It will also be appreciated that the functions of the control switching relay and traction motor contactor may also be performed using solid state electronic devices.

Referring to FIG. 2, the conventional reversing contactor pair has been replaced with a single three-phase contactor 12 and power switching relay 13. A time delay circuit 14 is also added to the control circuit. The purpose of providing this time delay circuit is to ensure that the relay contacts never close when current is flowing, and to ensure that the power switching relay 3 operates and closes its contacts before the main contactor 12 operates. It's for a reason. The time delay circuit 14 also prevents the power switching relay from opening its contacts before the contactor interrupts the current.

The operation of the circuit shown in FIG. 2 is similar to that shown in FIG. The operation is similar to that of the circuit illustrated in and previously described.

When the power switching relay 13 is activated, a time delay circuit is activated to attract the main contactor 12 for a short time after the power switching relay contacts are closed.

It is also possible to provide the power switching relay 13 with an auxiliary contact. This auxiliary contact energizes a time delay circuit 14 to prevent main contactor 12 from activating until the power changeover relay has been activated when selecting a direction of motor rotation that requires the power changeover relay to be activated. It can be arranged as follows. Following the closing of the power switching relay auxiliary contact, the KW source switches until the time the main contactor closes its contact - the inherent response time of the control circuit is sufficient to ensure that full contact pressure is obtained. If is long, it is possible to do without a time delay circuit. Although an electromechanical mechanism is illustrated in FIG. 2 for the power switching relay, it will be appreciated that solid state devices may be used in alternative embodiments.

In both FIG. 1 and FIG. 2, the phase discriminator circuit 7 is shown as being permanently connected to the input power supply. This is done by connecting the Kll to the input power supply so that the input power supply has a unidirectional phase rotation. ``In the event of a malfunction, this will result in the coil of the control switching relay 9 being permanently energized.
It may be undesirable for this coil to be permanently energized, ie, independent of the manner in which the input power source is connected.

In this case, it is necessary to provide an additional contact on the "open" button 10 and the "close" button 11, and to arrange this additional contact so that it closes before the main I button contact closes. These additional contacts are arranged in such a way that they are wired in parallel at the button and complete the circuit between the line 8 and the control switching relay 9.

Under these circumstances, the relay coil will only be energized if either the open or close button is pressed and the phase discrimination circuit requires the switching relay to be activated.

This circuit is useful in applications where the motor is required to rotate in one direction at all times, such as in sealed wet rotor chemical pumps with multiphase stator windings and integrated starter and retention circuits. It can also be used in applications where the motor shaft is not visible and its direction of rotation cannot be determined by other methods. In such an application example, the circuit illustrated in FIG. 1 or 2 cannot be used, and the close button 11 cannot be used.
and the associated switching contact of the control switching relay 9 are omitted, leaving the button 10 as the motor start button.

Referring to FIG. 3, the power supply circuit has power supply terminals L1, L2, and L3, which terminals are connected to a six-phase power supply in use, and from which line A is connected.

B and C extend through a phase reversing contactor set 31 to motor terminals TI, T2 and T3. In one state, the contactor set 31 connects wires A and B to motor terminal T1, respectively.
and 72 to rotate the electric motor 3 in one direction, and in the other state, wires A and B are connected to terminals T2 and TI, respectively.
K connection to reverse the phase rotation direction at the motor terminals,
Rotate the motor in the opposite direction.

The state of the contactor set 61 is controlled by a control input IK supplied to the contactor set 31 via a logic board r32. The first control force I causes the electric motor 3 to rotate in one direction, and the second control force I causes the electric motor 3 to rotate in the opposite direction.

For example, terminal I, 1. Even if L2 and L3 are incorrectly connected to a 6-phase power supply, jF! To ensure that the motor always rotates in a predetermined direction for each of the first and second control inputs, a control circuit including a phase discrimination circuit as described below and supplies a logic O or a logic 1 to the logic board 32 depending on the phase order detected by this control circuit. This is 5K
L, the phase l[order] is associated with the actuation input signal, and therefore the terminal L1. Regardless of the direction of phase rotation at L2 and L3, the output from logic board 62 sets the state of contactor set 31 and therefore the direction of phase rotation at terminals T1, T2 and 73. Thus, in the case of a valve actuator, the first input I can be arranged reliably to produce 30 revolutions of the electric motor in order to drive the valve actuator in the direction of closing the valve, for example; The second input I can also be arranged to produce 30 revolutions of the motor to drive the valve actuator in the direction that the valve opens.

The control circuit includes a rectifier circuit 25 whose input terminals X, Y are connected to lines A, B and 14 through resistors R, R, and R and capacitor C as shown.
1 GK is connected. Figure 4 shows terminals X, Y of lines A, B and C.
The voltage v1 shown in FIG. 4 is the voltage between lines A and B, ie the voltage between line A and common point N, and is the equivalent circuit of the connection to 0. Also, voltage ■ is the voltage between lines C and B, that is, line A and the common point N
and is given by -■zi*cart.

The open circuit voltage vxY appearing between terminals X and Y is given by the following equation.

v='/-V has a value of vK vs. ta%-1 (xC1/R1), where xc is the reactance of capacitor C1. vYN is in phase Σ with v2, and vR2/(
If OV with a root mean square value of R3 in R2 is lagging with respect to VK, the voltage waveform shown in FIG. 5a will be generated. If V□ is in advance of v2, the voltage waveform shown in Figure 5b will be generated.

When V is 120° ahead of V, teLis
It can be seen that if (Xc1/R1) is 60 degrees and the magnitudes of XN and YN are the same, VxY will be zero.

Under these conditions, when vl lags v2 by 120°, XY has a considerable amplitude. This is achieved by selecting K.

The output terminal P (ltlK) of this bridge is connected to a light emitting diode 26 forming part of an optical isolator 270, which also contains a photodetector 28. When it indicates the phase rotation direction ABC, the light emitting diode 26
No light is emitted from the detector 28, and the detector 28 produces an output of 1 in binary code. However, when the voltage xY is greater than zero, light is emitted from the light emitting diode 26 and the detector 2
8 is a binary code and generates a 00 output to indicate the direction of phase rotation of the ACB.

As mentioned earlier, terminal L1. Correct connection of L2 and R3 should produce a phase rotation direction of ABC, but if they are incorrectly connected to produce a phase rotation direction of ACB, the binary code 00 output from the control circuit will be output. In relation to the operation control human power I, it is as if the terminal L1
, R2, and R3 would produce the same phase rotation at motor terminals T1, 〒2, and 73 as if the direction of the phase sequence in , R2, and R3 were ABC.

Thus, it will be appreciated that the present invention provides an arrangement that ensures that the polyphase motor operates in the required direction regardless of the phase order of the power supplies.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention when applied to a contactor/starter for reversing the phase of a valve actuating device, and FIG. A second embodiment of the invention as applied to a three-phase contactor is shown in FIG. 3, and FIG. As an example, FIG. 4 shows a voltage waveform derived from the equivalent circuit of the embodiment shown in FIG. 1-m-main power terminal, 2-m-control power terminal, 3----
3-phase induction motor, 4.5---contactor set, 7---
-Phase discrimination circuit, 9-m-control switching relay, 1O---
"r open" push button, 1l---r close" push button, 12-11 main contactor, 13-m-power switching relay, 14--
One time delay unit, 25-m-rectifier bridge, 26
---Light emitting diode, 27--optical isolator circuit, 28-m-photodetector, 31-m-set of contactors, 32--11 wheel processing board. Agents: Patent attorney Teru Ito and 3 other people Contag Jl Kontageta 2 Chu'Rai rK,

Claims (1)

[Claims] (!) It has a reversible multi-phase motor, and has a terminal mechanism for connecting to a multi-phase power source, and the terminal mechanism is coupled to the motor so that the direction of phase rotation of the power source at the motor terminals can be reversed. a control mechanism operable to act on the coupling mechanism to enable selection of the direction of rotation of the electric motor; 1. A valve actuating device comprising a control circuit operable to cause the direction of phase rotation at the motor terminals to be in a direction which causes rotation of the motor in any selected direction. (21) The control circuit detects the phase order in the terminal mechanism, and when the phase order of the power supply is in the first direction,
a phase discrimination circuit that generates a second output signal when the output signal of the first output signal is generated and the phase order is reversed;
and a second output signal such that the phase connection at the front motor terminals when the first output signal is present is opposite to that when the second output signal is present. (3) The control mechanism is operable to control the coupling mechanism such that the phase connections at the motor terminals are reversed when reversal of motor direction is selected. The second (2nd
The valve actuation device according to paragraph 1, wherein: (4) the phase discrimination circuit includes an optical isolator circuit, whereby the first and second output signals are extracted from a photodetector;
The valve actuation device according to item 1. (5) the optical isolator circuit includes a rectifier bridge circuit in which the light emitting device is connected between the output terminals of the bridge;
The light emitting de, when the orientation is ? connected between the terminals of the terminal mechanism such that the light emitting device is in the off state when the chair is in the on state and in the opposite orientation;
(6) The coupling mechanism comprises a contactor mechanism in the power supply line between the terminal mechanism and the motor terminal, and the energization of the contactor mechanism is controlled by the first and second terminals. Items 121 to (51) selectively controlled by the second output signal.
The valve actuation device according to any one of paragraphs. (71) the control mechanism for determining the electric lateral rotation direction is electrically distributed to control the energization of the contactor mechanism in combination with the control circuit for detecting the phase sequence of the power supply in the terminal mechanism; (8) The coupling mechanism includes a contactor mechanism and a switching relay connected in a power supply line between the terminal mechanism and the motor terminal, and The relay coil is energized by the W mentioned above.
clause (2), wherein a time delay circuit is selectively controlled by J1 and a second output signal and is provided for delaying activation of said contactor mechanism relative to said switching relay; The valve actuation device according to any one of items (5) to (5). (9) The control mechanism for determining the direction of rotation of the electric motor is configured to energize the contactor mechanism and to detect the phase sequence of the power supply in the terminal mechanism in combination with the control circuit for energizing the contactor mechanism and detecting the phase sequence of the power supply in the terminal mechanism. 182. The valve actuation device according to paragraph 181, wherein the valve actuation device is arranged at 5 to control the pressure. aI The control mechanism controls the control circuit so that the control circuit is enabled only when the control mechanism is activated and immediately before the control mechanism performs its action on the coupling mechanism. The valve operating device according to any one of the above.