JPH0527791Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] This invention relates to an auxiliary contact circuit for an electromagnetic contactor.

[Background technology]

The conventional push button operation circuit, as shown in Fig. 5,
When the switch 1 is turned on, the electromagnetic contactor 3 is energized through the switches 1 and 2, the auxiliary contact 3a of the electromagnetic contactor 3 is turned on, the electromagnetic contactor 3 is self-held, and the operation lamp 4 is lit. Further, when the main contact 3b of the electromagnetic contactor 3 is turned on, power is supplied to the motor 5. When the switch 2 is turned off, the self-holding of the electromagnetic contactor 3 is released,
Main contact 3b and auxiliary contact 3a are turned off, power supply to motor 5 is stopped, and operation lamp 4 is turned off.

The conventional automatic driving circuit, as shown in Figure 6,
When the changeover switch 6 is set to "auto", the external contact 7
When turned on, the electromagnetic contactor 8 is energized, its auxiliary contact 8a is turned on and the operation lamp 9 is lit, and the main contact 8b is turned on and power is supplied to the motor 10. When the external contact 7 is turned off, the power to the electromagnetic contactor 8 is stopped and the main contact 8b is turned off.
Then, the auxiliary contact 8a is turned off, power supply to the motor 10 is stopped, and the operation lamp 9 is turned off.

Such a circuit is built into the control panel,
The control circuit section consisting of parts other than the electromagnetic contactors 3 and 8 is mounted on a printed wiring board, and includes the windings of the electromagnetic contactors 3 and 8 and auxiliary contacts 3a and 8.
It is necessary to connect a to the printed wiring board, and 4
Since control wiring had to be carried out, wiring required time and effort, and there were many external connection points to the printed wiring board, there was also a problem in terms of reliability.

[Purpose of invention]

The object of this invention is to provide an auxiliary contact circuit for an electromagnetic contactor that can reduce the number of connecting wires between the electromagnetic contactor and other circuit parts.

[Disclosure of invention]

The auxiliary contact circuit of the electromagnetic contactor of this invention includes an external connection terminal to which the drive coil of the electromagnetic contactor that opens and closes the main contact is connected and outputs a current that opens and closes the electromagnetic contactor, and this external connection terminal. A current transformer that is electrically connected to a terminal and has a primary winding connected in series to the drive coil, and a current detector that inputs the output of the secondary winding of this current transformer and detects the current flowing through the drive coil. A circuit, an auxiliary contact switch element that responds to the output of this current detection circuit, and load circuits such as a display circuit and a holding circuit that are controlled by this auxiliary contact switch element are mounted on a printed wiring board.

Examples will be described below based on the drawings.

A first embodiment of this invention will be described based on FIG. In this push button operation circuit, when the switch 11 is turned on, the relay 13 is energized through the switches 11 and 12, its contact 13a is turned on, and the electromagnetic contactor 14 is energized. As a result, the main contact 14a of the electromagnetic contactor 14 turns on and the motor 1
5. Further, when the electromagnetic contactor 14 is energized, the current detection amplifier circuit 16 detects this exciting current via the current transformer 17, and the current detection amplifier circuit 1
6 turns on the transistor (for the auxiliary contact) 18. As a result, the relay 13 is energized through the transistor 18 and the switch 12 to form a self-holding circuit, and the state of power supply to the motor 15 is maintained, and at this time the operation lamp 19 is lit.

Next, when switch 12 is turned off, a self-holding circuit consisting of relay 13, electromagnetic contactor 14, current detection amplifier circuit 16, and transistor 18 is opened, power supply to motor 15 is stopped, and operation lamp 1
9 goes out. 20 is a power supply circuit.

In this way, in this embodiment, the auxiliary contact circuit consisting of the current transformer 17, the current detection amplifier circuit 16, and the transistor 18 is provided, so that the electromagnetic contactor 14 only needs the main contact 14a, and the electromagnetic contactor 14 and this Control circuit section consisting of other parts (mounted on printed wiring board: part surrounded by two-dot chain line)
It is now only necessary to connect the two wires with two wires, which simplifies wiring and shortens assembly time, and reduces the number of external connection points (points where screw connections are made), increasing reliability.

Additionally, an auxiliary contact is often required to perform interlock, interlocking, etc. when the electromagnetic contactor operates, but if an auxiliary contact circuit is provided in this way, one auxiliary contact is not required, so it is no longer necessary. The auxiliary contact built into the electromagnetic contactor can be used for other purposes, and even if an auxiliary relay or the like was required in the past, it can be made unnecessary.

In addition, when the control circuit section is made low-voltage, if the auxiliary contact of the magnetic contactor is directly connected to the low-voltage circuit, if the main contact and auxiliary contact of the magnetic contactor are shot during inspection, the high voltage of the low-voltage circuit will be removed. There is a risk that the power supply voltage will be applied and the light current circuit will be destroyed, but in this embodiment, the exciting current of the magnetic contactor 14 is taken in in an insulated state through the current transformer 17, so the light current circuit will not be destroyed. There isn't.

A second embodiment of this invention will be explained based on FIG. This automatic operation circuit is operated by the changeover switch 21
When the external contact 22 is turned on in the "automatic" state, the electromagnetic contactor 23 is energized, its main contact 23a is turned on, and power is supplied to the motor 24. Further, the current detection circuit 25 detects the excitation current of the electromagnetic contactor 23 via the current transformer 26, turns on the transistor (for auxiliary contact) 27, and lights up the operation lamp 28.

When the external contact 22 is turned off, the electromagnetic contactor 23
The power supply to the motor 24 is stopped, the main contact 23a is turned off, and the power supply to the motor 24 is stopped.
is turned off and the operation lamp 28 is turned off.
is the power supply circuit.

In addition, in FIG. 2, the portion surrounded by the two-dot chain line is mounted on the printed wiring board as a control circuit section.

The effects of this embodiment are similar to those of the first embodiment.

In addition, in the above embodiment, the electromagnetic contactors 14, 23
Although the transistors 18 and 27 are turned on when the transistors 18 and 27 are excited, they may be turned off instead.

A third embodiment of this invention will be explained based on FIG. This control device consists of a main body block BK 1, which is mounted on one printed wiring board and attached to the main body of the control panel case, and a main block BK ₂ , which is mounted on one printed wiring board and attached to the lid of the control panel case. Main power line (r line, s line: AC24V) and 1
It consists of a dedicated line _L1 for books and _a lid block _BK2 connected to the main body block BK1.

This will be explained in more detail below. First, if you set changeover switch SW ₁ to the position at hand (hand:
ON, OFF: OFF, AUTO: OFF). In this state, when switch PB _ON1 is turned on, r line → switch PB _OFF → diode
D ₁ → Switch PB _ON1 → Changeover switch SW ₁ → Dedicated line
L _{1 → Diode} D ₃ → _Resistor R ₂ → _Relay
Contact x ₁ of X ₁ turns on. As a result, R line - current transformer CT - contact x _{1 of relay x 1 -} magnetic contactor
The MC-thermal relay contacts are energized through the tm-S line path, and the electromagnetic contactor MC is energized and becomes operational. Further, when an excitation current flows through the electromagnetic contactor MC, the current detection circuit DT detects this excitation current via the current transformer CT, and turns on the transistor _Q4 . As a result, transistor _Q5 has a diode
Base current flows through D ₁₃ , resistor R ₁₀ , and transistor Q ₄ , turning on transistor Q ₅ . When this transistor _Q5 turns on, the s line →
Transistor Q ₅ → Diode D ₉ → Light emitting diode LED ₁ → Dedicated line L ₁ → Diode D ₈ → Resistor R ₈ , R ₉
→The light emitting part of photocouplers PC ₁ and PC ₂ → The other side is half-wave energized through the r line path, and the r line → switch
PB _OFF → Between emitter and base of transistor Q ₁ →
Resistor R ₁ → Light receiving part of photocoupler PC ₁ → Diode
One side is energized half-wave in the D ₇ → s line path, transistor Q ₁ is turned on, and the r line → switch is turned on.
PB _OFF → Transistor Q ₁ → Diode D ₂ → Changeover switch SW ₁ → Dedicated line L ₁ → Diode D ₃ → Resistor R ₂
→Relay X ₁ →Transistor Q ₂ →Diode D ₄ →
One side is half-wave energized in the s line path, relay X ₁
enters a self-holding state, and the magnetic contactor MC maintains its energized state. Also, the light receiving part of photocoupler PC ₂ turns on, and the indicator light circuit DP turns on the operation indicator lamp RL.
lights up, and light emitting diode LED ₁ also lights up. Note that the diode bridge DB ₂ and capacitor C ₃ are for the power supply of the current detection circuit DT.

As mentioned above, the auxiliary contact of the magnetic contactor MC is eliminated and the exciting current is detected by the current detection circuit DT.
When transistors Q ₄ and Q ₅ are turned on and off to take out the auxiliary contact output, the main block BK ₁
When mounted on a printed wiring board, the number of connection wires between the printed wiring board and the magnetic contactor MC can be reduced to two, simplifying wiring and shortening assembly time. can. Furthermore, the number of external connection points (points where screw connections are made) is reduced, and reliability can also be improved.

In addition, when an electromagnetic contactor operates, an auxiliary contact is often required for interlocking, interlocking, etc., but if an auxiliary contact circuit is provided in this way,
Since one auxiliary contact is no longer required, the auxiliary contact built into the electromagnetic contactor that is no longer needed can be used for other purposes, and even if an auxiliary relay or the like was required in the past, it can be made unnecessary.

Also, the main body block BK ₁ and the lid block
When the BK ₂ is powered to a low power source, if the auxiliary contact of the magnetic contactor is directly connected to the low power circuit, high power supply voltage will be applied to the low power circuit when the main and auxiliary contacts of the magnetic contactor are shunted during inspection. However, in this embodiment, the excitation current of the electromagnetic contactor MC is taken in in an insulated state through the current transformer CT, so the weak current circuit will not be destroyed.

Next, when the switch PB _OFF is turned off, the energization to the winding of the relay X ₁ is stopped, the self-holding of the relay X ₁ is released, the electromagnetic contactor MC becomes a de-energized state, and the operation is stopped. Further, the light receiving section of the photocoupler PC ₂ is turned off, and the indicator light circuit DP turns off the operation indicator lamp RL and turns on the stop indicator lamp GL.

Next, in an operating state where the self-holding state _of relay The current supply is stopped and the operation is stopped, the output of the current detection circuit DT disappears, transistors Q ₄ and Q ₅ are turned off, and the self-holding of relay X ₁ is released.
Operation indicator lamp RL goes out. In addition, by switching the contact tm to the normally open side, the R line - resistance
R ₁₁ - Diode bridge DB ₃ - Resistor R ₁₅ - Light emitting part of photocoupler PC _4A , PC _4B - Diode bridge
DB ₃ - Resistor R ₁₂ - Contact tm - The light receiving part of photocoupler PC _4A is turned on by energizing through the S line path.
Resistor R ₁₇ , photocoupler PC _4A photodetector, diode
Base current flows through _D14 to transistor _Q6 . As a result, s line → flicker circuit FC → transistor Q ₆ → diode D ₁₀ → light emitting diode
LED ₁ → Dedicated line L ₁ → Diode D ₈ → Resistor R ₈ , R ₉ →
The light emitting part of the photocouplers PC ₁ and PC ₂ is intermittently energized in half-wave on the other side through the path of the r line, and the transistor Q _1
is intermittently _turned on and _{tries to energize} relay This bypasses the light emitting diode LED ₂ and the base current flowing into the transistor Q ₂ through the resistor R ₃ and
Q ₂ is turned off and relay X ₁ is prohibited from being energized.
In addition, the light receiving part of photocoupler PC ₂ turns on intermittently, causing the indicator light circuit DP to turn on the error indicator lamp.
OL lights up and light emitting diode LED ₁ also flashes.

Next, in an abnormal state, when the contact tm of the thermal relay is reset (returned to the normally closed side), the power to the photocouplers PC _4A and PC _4B is stopped, the light receiving part of the photocoupler PC _4A is turned off, and the photocoupler
The intermittent half-wave energization to the light emitting parts of PC ₁ and PC ₂ on the other side stops, the light receiving part of photocoupler PC ₁ is turned off, transistor Q ₂ is completely turned off, and the light receiving part of photocoupler PC ₂ is also turned off. Indicator light circuit
DP turns off the abnormality indicator lamp OL, turns on the stop indicator lamp GL, and also turns off the light emitting diode LED ₁ . Furthermore, when the light receiving section of the photocoupler PC _4B is turned off, the transistor _Q3 is turned off and the transistor _Q2 is turned on, thereby canceling the inhibition of excitation of the relay _X1 . In this way, when the thermal relay trips, transistor _Q2 is turned off and relay _X1 is prohibited from being energized.
Even if power is intermittently applied from the flicker circuit FC to the light emitting part of the photocoupler PC ₁ , the light receiving part is intermittently turned on, and the transistor Q ₁ is intermittently turned on,
Relay X ₁ is not energized at all, and even if the thermal relay is restored while current flows from the flicker circuit FC and the light emitting part of photocoupler PC ₁ is lit (lighting off is delayed a little due to capacitor C ₂ ), it remains in operation. It is safe.

Next, in the stopped state, when external contact Z is turned on, R line - external contact Z - resistor R ₁₃ - diode bridge DB ₄ - resistor R ₁₆ - photocoupler
Light emitting part of PC ₅ - Diode bridge DB ₄ - Resistor
R ₁₄ - Photocoupler is energized through the S line path.
The light receiving section of PC ₅ turns on. As a result, the resistance R ₁₈ ,
The base current flows into the transistor Q ₇ through the light receiving part of the photocoupler PC ₅ and the diode D ₁₅ , turning on the transistor Q ₇ , and then through the resistor R ₁₉ , the transistor Q ₇ , and the diode D ₁₅ .
Base current flows through _Q8 , turning on transistor _Q8 . Therefore, r line → transistor
Q ₈ → Diode D ₅ → _Resistor R ₂ → Relay X ₁ → Transistor Q ₂ → Diode D ₄ → _The s line is about to be energized. Light emitting section → Light emitting diode LED ₁ → Dedicated line L ₁ → Changeover switch SW ₁ →
Switch PB _ON2 → Resistor R ₆ → Diode D ₁₂ → Half-wave current is applied to one side through the s line path, and photocoupler PC ₃
The light receiving section of is turned on, turning on transistor _Q3 , turning off transistor _Q2 , and inhibiting the excitation of relay _X1 . In this way, when external contact Z is turned on, transistor Q ₂ is turned off and excitation of relay X ₁ is prohibited, so when switching switch SW ₁ is at hand, external contact Z
can be completely disabled. Furthermore, only one dedicated line _L1 is required to connect the main body block _BK1 and the lid block _BK2 .

Next, when changeover switch SW ₁ is set to automatic (remote) state (local: OFF, off: OFF, automatic:
ON) will be explained. In this state,
When external contact Z turns on, R line - external contact Z - resistor R ₁₃ - diode bridge DB ₄ - resistor R ₁₆
- Light emitting part of photocoupler PC ₅ - Diode bridge
DB ₄ - Resistor R ₁₄ - Power is applied through the S line path, the light receiving section of photocoupler PC ₅ is turned on, transistors Q ₇ and Q ₈ are turned on, and R line → transistor Q ₈ → diode D ₅ → resistor R ₂ → Relay X ₁ → Transistor Q ₂ → Diode D ₄ → Half-wave current is applied in _the s line path, _relay
is turned on, the magnetic contactor MC is energized, and becomes operational. Further, the current detection circuit DT detects the excitation current and turns on the transistors Q ₄ and Q ₅ . As a result, the s line → diode D ₉ → light emitting diode LED ₁ → dedicated line L ₁ → diode D ₈ → resistors R ₈ , R ₉ → light emitting part of photocouplers PC ₁ , PC ₂ → the other half wave on the r line path. Energized, photocoupler PC ₂
The light receiving section of is turned on, the indicator light circuit DP lights up the operation indicator lamp RL, and the light emitting diode LED ₁ also lights up.

Next, when external contact Z is turned off, power to the light emitting part of photocoupler PC ₅ is stopped, and the photocoupler
When the light receiving part of PC ₅ is turned off, the transistor Q ₇ ,
Q ₈ is turned off, relay X ₁ is no longer energized, and
Contact _x1 is turned off, and the magnetic contactor MC becomes de-energized, and the operation is stopped. Furthermore, by eliminating the excitation current, transistors Q ₄ and Q ₅
is turned off, power to the light emitting part of photocoupler PC ₂ is stopped, the light receiving part of photocoupler PC ₂ is turned off, and the indicator light circuit DP turns off the operation indicator lamp RL, turns on the stop indicator lamp GL, and starts emitting light. Diode LED ₁ also turns off.

During operation with the external contact Z turned on, when the thermal relay trips and the contact tm switches to the normally open side, the excitation of the electromagnetic contactor MC is stopped and the operation is stopped. Furthermore, as the excitation current disappears, transistors Q ₄ and Q ₅ are turned off, power to the light emitting part of the photocoupler PC ₂ is stopped, the light receiving part is turned off, and the indicator lamp circuit DP turns off the operation indicator lamp RL. Turn off the light. Furthermore, the photocoupler
Turn on power to PC _4A and PC _4B to turn on their light receiving sections. As a result, s line → Fritzker circuit FC →
Transistor Q ₆ → Diode D ₁₀ → Light emitting diode LED ₁ → Dedicated line L ₁ → Diode D ₈ → Resistor R ₈ , R ₉
→ Light emitting parts of photocouplers PC ₁ and PC ₂ → The r line is intermittently energized, and the indicator light circuit DP lights up the error indicator lamp OL. Also, by turning on the light receiving part of photocoupler PC _4B , the transistor
Turn off Q ₂ and inhibit energization of relay X ₁ .

After that, when the thermal relay is reset, the power to the light emitting parts of photocouplers PC _4A and PC _4B is stopped.
Those light receiving sections are turned off. As a result, the indicator light circuit DP turns off the abnormality indicator lamp OL and turns on the stop indicator lamp GL, and also turns off the transistor _Q2.
Turn on to release the prohibition of excitation of relay _X1 .

Next, the case where the changeover switch SW ₁ is turned off (hand: OFF, off: ON, automatic: OFF) will be explained. In this state, relay _X1 is not energized at all even if switch PB _ON1 is turned on. Also,
When external contact Z turns on, the transistor
Q ₈ turns on and r line → transistor Q ₈ →
Diode D ₅ → Resistor R ₂ → Relay X ₁ → Transistor Q ₂ → Diode D ₄ → It tries to be energized through the path of S line, but R line → Transistor Q ₈ →
Diode D ₅ → Light emitting part of photocoupler PC ₃ → Light emitting diode LED ₁ → Dedicated line L ₁ → Changeover switch SW ₁ →
Resistor R ₇ → diode D ₆ → s line is energized for half a wave on one side, and the light receiving part of photocoupler PC ₃ is turned on, transistor Q ₃ is turned on, and transistor Q ₂ is turned on.
is turned off, prohibiting the excitation of relay _X1 , and the stop indicator lamp GL lights up.

_C1 is a capacitor that delays the excitation stop of relay _X1 for a certain period of time, _D11 is a diode, _DB1 is a diode bridge, and _C4 and _C5 are capacitors.

Switch PB _ON2 cuts off the current flowing to resistor _R6 the moment switch PB _ON1 is pressed, and r-
This is to prevent the voltage drop on the s line and to make it easier for relay _X1 to be excited even if the power supply voltage drops.
You don't have to. Once relay _X1 is turned on, it will not open even if the voltage drops slightly, so there is no problem even if switch PB _ON2 is turned on afterwards.

A fourth embodiment of this invention will be described based on FIG. This control device uses a contact ry of a relay RY in place of the external contact Z in FIG. 3, and the on/off of this contact ry is performed by the following configuration. When switch SW ₂ is turned on, power is applied through the R line - switch SW ₂ - switch SW ₃ - relay RY - S line, relay RY is energized, contact ry is turned on, and magnetic contactor MC is energized.
Contact mc turns on, forming a self-holding circuit for relay RY, and when switch SW ₃ is turned off,
The above self-holding is released and the excitation of the electromagnetic contactor MC is stopped.

Other configurations and effects are the same as those in FIG. 3.

In addition, in the case of the configuration shown in Fig. 4, when the switch SW 1 is put into operation with the switch SW ₁ at hand, when the switch SW ₁ is switched to automatic, the relay on the route passing through the dedicated line L ₁ Even if the current to X ₁ is momentarily cut off, the capacitors C ₁ ,
Due to the action of C ₂ , the relay X ₁ and photocoupler PC ₁ are de-energized for a certain period of time, so even when the changeover switch SW ₁ is switched, the operating state continues as it is, and it can be used in a remote location (for example, a monitoring board). There is no need to go and operate _switch SW _{2 located} at All you need to do is set it to the (distant) state, and the automatic (distant) state during inspections, etc.
It is very easy to restart the system. Moreover, the superiority of hand-held operation can be ensured (when it is held at hand, even if operated from a distance, it does not become operational) and is safe.

In addition, there is a switch to switch from the remote state to the local state.
The operating state continues even when SW ₁ is switched.

[Effect of idea]

According to the control device of this invention, an electromagnetic contactor,
It is possible to reduce the number of connection wires between other circuit parts, that is, load circuits such as display circuits and holding circuits, which reduces assembly time, and also improves reliability by reducing the number of external connection points. can. Furthermore, since the configuration is such that the current flowing through the drive coil is detected, there is no false detection and the detection reliability is high.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a first embodiment of this invention, Fig. 2 is a circuit diagram of a second embodiment of this invention, Fig. 3 is a circuit diagram of a third embodiment of this invention, and Fig. 4 is a circuit diagram of a third embodiment of this invention. The figure is a circuit diagram of a fourth embodiment of this invention, and FIGS. 5 and 6 are circuit diagrams of conventional examples, respectively. 14...Magnetic contactor, 16...Current detection amplifier circuit, 17...Current transformer, 18...Transistor.

Claims (1)

[Scope of utility model registration request] an external connection terminal to which a drive coil of an electromagnetic contactor that opens and closes the main contact is connected and outputs a current that opens and closes the electromagnetic contactor; A current transformer having a secondary winding connected in series; a current detection circuit that receives the output of the secondary winding of the current transformer and detects the current flowing through the drive coil; and a current detection circuit that responds to the output of the current detection circuit. A switch element for an auxiliary contact, a display circuit controlled by the switch element for an auxiliary contact,
An auxiliary contact circuit for an electromagnetic contactor that includes a load circuit such as a holding circuit mounted on a printed wiring board.