JP2006318661A - Electromagnetic contactor drive circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic contactor drive circuit with wasteful power consumption restrained, simply structured at a low price, without undue upscaling of a device. <P>SOLUTION: The circuit includes an input voltage source 3 with a high voltage and a retention voltage source 2 with a low voltage set by a direct current power source or a direct current power source with the alternate current power source rectified, an electromagnetic coil of an electromagnetic contactor 6 connected with the retention voltage source 2 through a switch 4, a series connected body a constantly closed contact 6b of the electromagnetic contactor connected in parallel with the electromagnetic coil and an auxiliary relay 5, a constantly open contact 5a of the auxiliary relay connected between the electromagnetic coil and the input voltage source 3, and flywheel diodes 8, 9 connected in parallel with the auxiliary relay and the electromagnetic coil, respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic contactor driving circuit, and more particularly to an AC / DC shared electromagnetic contactor driving circuit capable of driving an exciting coil of an electromagnetic contactor with both an AC power source and a DC power source.

FIG. 2 is a circuit diagram showing an example of an electromagnetic contactor driving circuit that has been used most frequently.
As shown in this figure, a DC power source 11 is connected to a series connection body of an electromagnetic coil 6 of an electromagnetic contactor and a holding resistor 12 via an operation switch 4 for turning on the electromagnetic contactor.

  Reference numeral 10 denotes a holding switch connected in parallel to the holding resistor 12, which is used in conjunction with the stroke of the electromagnet. If the operation switch 4 is closed with the holding switch 10 closed, the holding resistor 12 is short-circuited by the holding switch 10, so that the entire voltage of the DC power source 11 is applied to the electromagnetic coil 6, and the starting current is Flows, and adsorption energy is given to an electromagnet (not shown) to be attracted.

  After the adsorption, the holding switch 10 is opened and the holding resistor 12 is inserted in series with the electromagnetic coil 6 so that a small current necessary for holding is obtained. Further, when the electromagnetic coil 6 is released, the operation switch 4 is opened. In this system, since the holding resistor 12 is used to reduce the current required for suction holding, there is a disadvantage that wasteful power is consumed.

  In order to eliminate this drawback, an AC / DC shared electromagnetic contactor or the like has been proposed (see, for example, Patent Document 1). For example, the electromagnetic coil is divided into two for charging and holding, and switched by a semiconductor switch. Proposals have been made such as switching the current flowing through the individual electromagnetic coils by a semiconductor switch between turning on and holding.

JP 2002-184283 A

  The conventional magnetic contactor drive circuit is configured as described above, and when switching the current of the electromagnetic coil to a small current that is in the holding state, the holding resistor is connected in series, so that unnecessary power consumption due to the resistor is consumed. there were. Also, in order not to waste useless power due to the resistance, two electromagnetic coils for starting and holding are provided from the beginning, and these electromagnetic coils are switched by a semiconductor switch, and the electromagnetic coil is 1 In other words, there is a semiconductor switch that switches between a current that flows when it is turned on and a current that flows when it is held. However, there are problems such as a complicated and large-scale apparatus.

  The present invention has been made in order to solve the above-described problems, and is an electromagnetic contactor drive that can suppress wasteful power consumption and can be easily configured at a low cost without increasing the size of the apparatus. An object is to provide a circuit.

  The electromagnetic contactor drive circuit according to the present invention includes a high voltage input voltage source and a low voltage holding voltage source set by a DC power source or a DC power source rectified from an AC power source, and a switch to the holding voltage source. Connected to the electromagnetic coil, a series connection body of the normally closed contact of the electromagnetic contactor and the auxiliary relay connected in parallel to the electromagnetic coil, connected between the electromagnetic coil and the input voltage source A normally open contact of the auxiliary relay, and a flywheel diode connected in parallel to the auxiliary relay and the electromagnetic coil.

  According to the present invention, as the input voltage of the magnetic contactor, two types of DC voltage sources for charging and holding are set from a DC power source obtained by full-wave rectification of the AC power source or a direct DC power source. Then, after applying DC voltage to the electromagnetic coil for the first time and detecting that the electromagnetic coil is excited by the auxiliary normally closed contact of the magnetic contactor, the auxiliary normally closed contact is connected in series to the auxiliary relay. For this reason, when the auxiliary relay is de-energized, the auxiliary normally open contact of the auxiliary relay is used to switch from the input DC voltage to the holding DC voltage application. Each is applied at the optimum voltage, so there is no wasted power consumed by resistors, etc., and switching between turning on and holding is not a large-scale operation using a semiconductor switch, etc. The price of the device is obtained.

  In addition, when only 60 Hz specifications are supplied to the market as electromagnetic contactor specifications, for example, when it is necessary to drive with a 400 Hz power supply, there is no need to divide into two types of electromagnetic coils for input and holding. Since a direct current power source can be created by full-wave rectifying a 400 Hz power source for one electromagnetic coil of 60 Hz specification as it is, a device that can be driven regardless of the frequency can be obtained.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of the first embodiment. In this figure, by providing a tap on the output side of the transformer 1 connected to the single-layer AC power supply AC, two types of voltage sources, a high voltage input voltage source and a low voltage holding voltage source, are created. The charging voltage is applied to the full-wave rectifier 3, and the holding voltage is applied to the full-wave rectifier 2.

  On the output side of the full-wave rectifier 2, a series connection body of an electromagnetic coil of an electromagnetic contactor 6 and a diode 7 and an normally closed contact 6 b which is an auxiliary b contact of the electromagnetic contactor 6 and an auxiliary relay 5 are connected via an operation switch 4. Are connected in parallel. On the output side of the full-wave rectifier 3, a normally open contact 5 a that is an auxiliary a contact of the auxiliary relay 5 enters in series, and is connected between the electromagnetic coil of the electromagnetic contactor 6 and the diode 7. Flywheel diodes 8 and 9 for absorbing the back electromotive force of the coils are connected in parallel to the electromagnetic coils of the auxiliary relay 5 and the magnetic contactor 6, respectively.

  Next, the operation of the first embodiment will be described. When the operation switch 4 is turned on, a low voltage for holding the full-wave rectifier 2 is applied to the electromagnetic coil of the auxiliary relay 5 through the normally closed contact 6b to excite the auxiliary relay 5, and simultaneously the electromagnetic coil of the electromagnetic contactor 6 Also, a low voltage for holding is applied. At this time, the magnetic contactor 6 does not operate because the voltage is low. As a result of the operation of the auxiliary relay 5, the auxiliary a contact 5 a is closed, and the electromagnetic coil of the electromagnetic contactor 6 is applied with a high input voltage supplied from the full-wave rectifier 3 and is operated by being excited.

  As a result, the auxiliary b contact 6b of the electromagnetic contactor 6 is opened, and the electromagnetic coil of the auxiliary relay 5 is not excited. As a result, the auxiliary a contact 5a is opened, and the electromagnetic coil of the electromagnetic contactor 6 is switched from the input voltage of the full wave rectifier 3 to the holding voltage of the full wave rectifier 2, and the electromagnetic coil of the electromagnetic contactor 6 is excited. Maintained and operation continues. Next, when the operation switch 4 is opened, the electromagnetic coil of the magnetic contactor 6 is de-energized and released.

  In the above-described first embodiment, the resistor 1 is not used in order to switch between the voltage for charging and holding, and two types of voltage for charging and holding are created by the transformer 1, so the resistance is wasted. Power consumption can be prevented. Further, the switching of the input voltage and the holding voltage is made non-excited by opening the auxiliary b contact 6b which detects that the electromagnetic coil of the electromagnetic contactor 6 is excited and operated, and by opening the auxiliary a contact 5a. Since the input voltage is switched to the holding voltage, it can be easily configured and an inexpensive device can be obtained as compared with a method using a semiconductor switch.

  Furthermore, when the auxiliary relay 5 is de-excited by the auxiliary b contact 6b, the effect of the flywheel diode 8 delays the time for the auxiliary relay 5 to be released.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the AC power supply AC is shown as a single phase in FIG. 1, and the transformer 1 and the full-wave rectifiers 2 and 3 are all shown as a single phase, but the AC power supply AC is a three-phase AC power supply. It is good. Further, the same effect can be obtained by connecting a direct current power source directly to each direct current output side instead of the full wave rectifiers 2 and 3 in FIG.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described. In the first embodiment described above, the switching timing from the input voltage to the holding voltage is delayed by the operation timing of the auxiliary relay 5 after the opening operation of the auxiliary b contact 6 b of the electromagnetic contactor 6. If the auxiliary relay 5 is used as a time relay and is operated with a delay of about 1 second, a more reliable closing operation can be performed.

It is a circuit diagram which shows the structure of Embodiment 1 of this invention. It is a circuit diagram which shows the conventional electromagnetic contactor drive circuit.

Explanation of symbols

1 Transformer 2, 3 Full wave rectifier 4 Operation switch 5 Auxiliary relay,
5a normally open contact, 6 magnetic contactor, 6b normally closed contact, 7 diode,
8, 9 Flywheel diode.

Claims (3)

  A high voltage input voltage source set by a DC power source or a DC power source rectified from an AC power source, a low voltage holding voltage source, an electromagnetic coil of an electromagnetic contactor connected to the holding voltage source via a switch, A series connection of a normally closed contact of the electromagnetic contactor connected in parallel to the electromagnetic coil and an auxiliary relay, a normally open contact of the auxiliary relay connected between the electromagnetic coil and the input voltage source, and An electromagnetic contactor drive circuit comprising flywheel diodes connected in parallel to the auxiliary relay and the electromagnetic coil, respectively.   2. The electromagnetic contactor drive circuit according to claim 1, wherein the AC power source is a single-phase or three-phase AC power source.   The electromagnetic contactor drive circuit according to claim 1 or 2, wherein the auxiliary relay is a time relay.

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