JP2876540B2 - Power supply for electromagnet applied equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power supply device for applying an electric excitation signal for setting an excitation coil of an electromagnet applied device to a positive excitation state or a reverse excitation state. More specifically, an electromagnetic chuck not using a permanent magnet, an electromagnetic chuck using a non-switchable permanent magnet and a switchable permanent magnet, an electromagnetic chuck using a switchable permanent magnet but not using a non-switchable permanent magnet, and an electromagnet The present invention relates to a power supply device for causing a voltage or current for positive excitation, reverse excitation, or demagnetization to act as an excitation signal on an excitation coil of an electromagnet-applied device such as a demagnetizer using the same.

(Prior art) As one of the power supply devices for applying an exciting voltage to an exciting coil of an electromagnet applied device, a rectifying circuit for generating a DC exciting voltage by full-wave rectifying an AC, and a rectifying circuit on an input terminal side. Some include arranged control rectifiers, such as thyristors, and control circuits that generate firing pulses for the control rectifiers. In this power supply device, the control circuit generates a firing pulse whose phase is shifted by a predetermined value with respect to the alternating current input to the rectifier circuit.

However, in this power supply device, the value of the excitation voltage output from the rectifier circuit is changed because the value of the excitation voltage is changed by changing the firing time of the control rectifier element, that is, the generation time of the firing pulse by a predetermined value. It depends on the frequency of the alternating current input to the power supply.

In particular, a power supply device including a setting device for setting a desired excitation voltage value, and generating a firing pulse shifted by a value determined by a value set in the setting device with respect to AC input to the rectifier circuit, This has the advantage that the excitation voltage can be set to an arbitrary value.On the other hand, the value of the excitation voltage is changed by changing the time at which the ignition pulse is generated by a value determined by the value set in the setting unit. There is a problem that the value of the voltage differs depending on the frequency of the alternating current input to the power supply device. As a result, for example, when a power supply device for commercial AC power of 50 Hz is used in an area where the frequency of commercial AC power is 60 Hz, the value of the excitation voltage output from the rectifier circuit greatly differs from the value set in the setting device. I will.

(Problems to be Solved by the Invention) It is an object of the present invention to provide a power supply device for an electromagnet applied device that generates an excitation signal of a predetermined value even when used in an area where the frequency of commercial AC power is different. I do.

(Means for Solving the Problems, Functions and Effects of the Invention) A power supply device for applying an electric excitation signal for setting an excitation coil of an electromagnet applied device to a positive excitation state or a reverse excitation state according to the present invention includes: Means for generating an electric excitation signal by rectifying the excitation signal, the excitation signal generation means comprising a control rectifying element for adjusting the value of the excitation signal, and a frequency for generating an electric signal for specifying the AC frequency A signal generating unit, based on an output signal of the frequency signal generating unit, generating a pulse signal having a phase corresponding to the output signal of the frequency signal generating unit, and outputting the pulse signal as a control signal to the control rectifier. Control means for selectively switching the polarity of an excitation signal applied to the excitation coil so as to selectively keep the excitation coil in a positive excitation state or a reverse excitation state; Instruction means for instructing the start of the operation of the electronic equipment or instruction means for instructing the start and stop of the operation of the electromagnet applied equipment. The control means includes:
A processing circuit is provided for generating the pulse signal and a switching signal for controlling the switching means in order to keep the excitation coil in a predetermined excited state when the start or stop of the operation is instructed by the instruction means.

If the frequency of the AC is 50 Hz, the control means generates a pulse signal that is phase-shifted with respect to the AC by a value corresponding to 50 Hz.If the frequency of the AC is 60 Hz, the control unit generates a phase signal with respect to the AC by a value corresponding to 60 Hz. A pulse signal is generated. When the start or stop of the operation is input to the control means, a pulse signal and a switching signal are generated from the processing circuit, whereby the excitation coil is set to a predetermined excitation state.

The power supply device includes an electromagnetic chuck using a switchable permanent magnet and a non-switchable permanent magnet, an electromagnetic chuck using a switchable permanent magnet but not using a non-switchable permanent magnet, and an electromagnetic chuck using no permanent magnet. It can be used as a power supply device for various electromagnetic chucks and demagnetizers, such as an electromagnetic chuck that demagnetizes a magnetic material when a work surface that adsorbs a magnetic material is de-energized, a demagnetizer that demagnetizes a magnetic material, and the like. .

Therefore, according to the present invention, the ignition timing of the control rectifying element is determined by the frequency of the alternating current regardless of the power supply for the electromagnetic chuck or the demagnetizer that rectifies the alternating current using the control rectifying element. As a result, the power supply is switched to a commercial AC power frequency of 50
The excitation signal output from the rectifier has a predetermined value, and the excitation coil is in a predetermined excitation state, regardless of whether it is used in the Hz region or the 60 Hz region.

As described in claim (2), when the start of the operation is instructed by the instructing means, the processing circuit causes the pulse signal and the switching means to keep the exciting coil in the positively excited state for a predetermined time. And a switching signal for controlling When the start of operation is instructed, the power supply generates an excitation signal for keeping the excitation coil in the positive excitation state for a predetermined time. For this reason, this power supply device is a power supply device for an electromagnetic chuck using a switchable permanent magnet and a non-switchable permanent magnet, or an electromagnetic chuck using a switchable permanent magnet but not using a non-switchable permanent magnet. It can be used as a power supply for

As described in claim (3), the processing circuit includes: a pulse signal for generating an excitation signal that gradually attenuates after the instruction to stop the operation by the instruction means;
A switching signal for controlling the switching means can be generated so that the exciting coil repeats the forward excitation state and the reverse excitation state at predetermined time intervals. This power supply device outputs an alternating voltage or an alternating current that gradually decreases after an instruction to stop the operation is issued. For this reason, this power supply device uses a power supply device for an electromagnetic chuck that demagnetizes the magnetic material when the work surface that attracts the magnetic material is de-energized, and a permanent magnet that is switchable but cannot be switched. It can be used as a power supply device for an electromagnetic chuck that does not use any.

As described in claim (4), the processing circuit gradually reduces the pulse signal and the excitation coil between the forward excitation state and the reverse excitation state after the instruction to stop the operation is given by the instruction means. And a processing circuit for generating a switching signal for controlling the switching means so as to be repeated at predetermined time intervals. After being instructed to stop the operation, the power supply repeatedly outputs the excitation signals having the opposite polarities alternately at gradually decreasing time intervals. For this reason, this power supply device uses a power supply device for an electromagnetic chuck that demagnetizes the magnetic material when the work surface that attracts the magnetic material is de-energized, and a permanent magnet that is switchable but cannot be switched. It can be used as a power supply device for an electromagnetic chuck that does not use any.

As described in claim (5), the processing circuit controls the pulse signal and the switching means so as to keep the exciting coil in the reverse excitation state for a predetermined time after the instruction to stop the operation is given by the instruction means. And a processing circuit for generating a switching signal. This power supply device outputs an excitation signal of the opposite polarity for a predetermined time after an instruction to stop the operation is issued. Therefore, this power supply device can be used as a power supply device for an electromagnetic chuck that demagnetizes a magnetic material when the work surface is de-energized. The electromagnetic chuck to which this power supply device can be applied includes an electromagnetic chuck that does not use a permanent magnet, an electromagnetic chuck that uses a non-switchable permanent magnet and a switchable permanent magnet, and an electromagnetic chuck that uses a switchable permanent magnet but cannot switch. There are electromagnetic chucks that do not use permanent magnets.
However, this power supply device is suitable as a power supply device for an electromagnetic chuck using permanent magnets that cannot be switched and permanent magnets that can be switched.

As described in claim (6), the processing circuit controls the switching means so that the pulse signal and the excitation coil are in a reverse excitation state after the instruction is given by the instruction means to stop the operation. A switching signal to be generated for a predetermined time, and then further, the pulse signal for generating an excitation signal that gradually attenuates, and the excitation coil repeats a positive excitation state and a reverse excitation state at predetermined time intervals. A processing circuit for generating a switching signal for controlling the switching means. This power supply device outputs an excitation signal having a reverse polarity for a predetermined time after an instruction to stop the operation is given, and then outputs an alternating voltage or an alternating current that gradually decreases. Therefore, this power supply device can be used as a power supply device for an electromagnetic chuck that demagnetizes a magnetic material when the work surface is de-energized. The electromagnetic chuck to which this power supply device can be applied includes an electromagnetic chuck that does not use a permanent magnet, an electromagnetic chuck that uses a non-switchable permanent magnet and a switchable permanent magnet, and an electromagnetic chuck that uses a switchable permanent magnet but cannot switch. There are electromagnetic chucks that do not use permanent magnets.
However, this power supply device is suitable as a power supply device for an electromagnetic chuck using permanent magnets that cannot be switched and permanent magnets that can be switched.

As described in claim (7), the instructing means is means for instructing start and stop of the operation of the electromagnet applied device, and the processing circuit is configured to, after the instructing means instruct the operation stop, The pulse signal and a switching signal for controlling the switching means to switch the polarity of the excitation signal applied to the excitation coil are generated for a predetermined time, and then the pulse signal and the excitation coil are in a positive excitation state. A processing circuit for generating a switching signal for controlling the switching means so as to repeat the reverse excitation state at gradually decreasing time intervals may be provided. The power supply device outputs an excitation signal of the opposite polarity for a predetermined time after the stop of the operation is instructed, and then repeatedly outputs an excitation signal of the opposite polarity alternately at gradually decreasing time intervals. Therefore, this power supply device can be used as a power supply device for an electromagnetic chuck that demagnetizes a magnetic material when the work surface is de-energized. Electromagnetic chucks to which this power supply device can be applied include an electromagnetic chuck using no permanent magnet, an electromagnetic chuck using a non-switchable permanent magnet and a switchable permanent magnet,
There is also an electromagnetic chuck that uses switchable permanent magnets but does not use non-switchable permanent magnets. However, this power supply device is suitable as a power supply device for an electromagnetic chuck using permanent magnets that cannot be switched and permanent magnets that can be switched.

As set forth in claim (8), the instruction means is means for instructing the start of operation of the electromagnet applied device, and the processing circuit is configured to gradually start the operation after the instruction means instructs the start of operation. A processing circuit for generating the pulse signal for generating the excitation signal to be attenuated, and a switching signal for controlling the switching means so that the excitation coil repeats the positive excitation state and the reverse excitation state at predetermined time intervals. Can be prepared. Since this power supply outputs an alternating voltage or an alternating current that gradually decreases when the start of operation is instructed, this power supply should be used as a power supply for a demagnetizer that demagnetizes a magnetic material. Can be.

As described in claim (9), after the start of the operation is instructed by the instructing means, the pulse signal and the exciting coil are repeatedly switched between the positive excitation state and the reverse excitation state at gradually decreasing time intervals. A processing circuit for generating a switching signal for controlling the switching means can be provided. When the start of the operation is instructed, the power supply unit repeatedly outputs the excitation signals having the opposite polarities alternately at gradually decreasing time intervals. For this reason, this power supply can be used as a power supply for a demagnetizer.

As in the power supply device according to claim (10), the frequency signal generating means may include a switch for specifying the frequency of the alternating current. In this case, the switch is switched every time the frequency of the commercial AC power is changed.

As in the power supply device according to claim (11), the frequency signal generating means includes a phase detector that outputs a signal when the alternating current has a predetermined phase angle, and the processing circuit is based on an output signal of the phase detecting means. The frequency of the alternating current can be determined.

As described in claim (12), the power supply further comprises:
The processing circuit includes means for setting a value of an exciting signal applied to the exciting coil, wherein the processing circuit is set in the setting means based on a value set in the setting means and an output signal of the frequency signal generating means. The pulse signal having a phase corresponding to the combination of the output signal of the frequency signal generating means and the output signal of the frequency signal generating means can be generated, and the pulse signal can be output to the control rectifier as a control signal. In this power supply,
If the AC frequency is 50 Hz, the control means generates a pulse signal that is phase-shifted with respect to AC by a value determined by a combination of the value set in the setting device and 50 Hz, and the AC frequency is 60 Hz.
In this case, a pulse signal whose phase is shifted with respect to AC by a value determined by a combination of the value set in the setting device and 60 Hz is generated. For this reason, the control rectifier is controlled so that the firing time is determined by the value set in the setting device and the AC frequency. As a result, for example, the power supply device is switched to a region where the frequency of the commercial AC power is 50 Hz. , And 60 Hz, the excitation signal output from the rectifier has the value set in the setting device.

As in the power supply device according to claim (13), the processing circuit can generate the pulse signal from when the start of the operation is instructed by the instruction means until the stop is instructed. The power supply device outputs an excitation signal for keeping the excitation coil in the positive excitation state from when the start of operation is instructed until the stop is instructed. For this reason, this power supply can be used as a power supply for an electromagnetic chuck that does not use permanent magnets.

(Embodiment) A power supply device 10 shown in FIG. 1 is used as a device for applying an excitation voltage to an excitation coil 12 of an electromagnet applied device such as an electromagnetic chuck.

The power supply device 10 includes a rectifier circuit 16 for rectifying an alternating current supplied from a commercial AC power source to a terminal 14 shown in FIG. 2A, and a switching circuit 18 disposed between the rectifier circuit 16 and the exciting coil 12.
And a control circuit 20 for controlling the switching circuit 18 and the control rectifier element 20 for opening and closing the flow path of the alternating current supplied from the terminal 14 to the rectifier circuit 16.

The rectifier element circuit 6 is a known bridge-type full-wave rectifier circuit using a plurality of rectifier elements such as diodes.
The switching circuit 18 switches the connection state between the output terminal of the rectifier circuit 16 and the terminal of the exciting coil 12 so that the rectifier circuit 16
The excitation voltage output from the
Is a known circuit for applying a forward or reverse direction in response to a switching signal supplied from the control circuit.

The control rectifier 20 is a known thyristor, such as a thyristor, that is turned on each time a control signal, i.e., a firing pulse is supplied from the control circuit 22 to the gate terminal, and closes the AC flow path until the voltage between the input and output terminals is inverted. Device. For this reason, if the phase of the ignition pulse is the same as that of the alternating current shown in FIG. 2A, the rectifier circuit 16 outputs the exciting voltage shown in FIG. 2B, which is applied to the exciting coil 12. You.

Instead of providing the control rectifier element 20 separately from the rectifier circuit 16, a control rectifier element such as a thyristor is used as the rectifier element in the rectifier circuit 16, and the rectifier element is generated by a pulse signal from the control circuit 22, that is, a firing pulse. You may make it control.

The power supply device 10 also includes a transformer 24 in which the alternating current input to the terminal 14 is supplied to the primary coil, and a phase detection circuit 26 that detects the phase of the alternating current obtained in the secondary coil of the transformer 24.

The phase detection circuit 26 is a known zero-cross detector that outputs an electrical pulse signal, that is, a zero-cross signal when the alternating voltage input to the terminal 14 is zero volts. Therefore, when the AC frequency input to the terminal 14 is 50 Hz, a zero-cross signal of 100 Hz is output from the detector 26 as a phase detection signal. In contrast, terminal 14
Is 60 Hz, the detector 26 outputs a zero-cross signal of 120 Hz as a phase detection signal. The zero cross signal from the detector 26 is supplied to the arithmetic circuit 28 of the control circuit 22.

The power supply device 10 further includes a switch 30 for instructing the start of the operation of the electromagnet applied device, a switch 32 for instructing the stop of the operation, and a setting device 34 for setting a desired excitation voltage. Each of the switches 30 and 32 is a push button switch that generates an electrical logic signal indicating that the switch is depressed, and is connected between the input terminal of the arithmetic circuit 28 and the ground.

Instead of using the switches 30 and 32, a single switch may be used, or a residual contact type switch or a double button switch may be used. When the power supply device 10 is used as a power supply device for an electromagnetic chuck, a switch for instructing the start of demagnetization may be provided.

The setting device 34 is a known device capable of manually changing a setting value. Examples of such setting devices include a variable resistor and a voltage value obtained by the variable resistor, which is a binary value corresponding to the voltage value. A circuit including an A / D converter for converting the code into a code, or a digital switch that outputs a set voltage value in a binary code can be used. Setting device 34
Is also connected to another input terminal of the arithmetic circuit 28.

The control circuit 22 includes, in addition to the arithmetic circuit 28, a clock signal generating circuit 36 having a frequency higher than the frequency of the AC supplied to the terminal 14, a binary counter 38 for calculating the clock signal, and an arithmetic circuit 28. Memory provided to accompany
40, a firing pulse generating circuit 42 for firing the control rectifier 20 and a drive circuit 44 for controlling the switching circuit 18 based on a signal supplied from the arithmetic circuit 28.

The count value of the counter 38 is read by the arithmetic circuit 28 and cleared by a clear signal from the arithmetic circuit 28 every time a zero cross signal is supplied from the phase detection circuit 26 to the arithmetic circuit 28. The memory 40 stores various data that is the basis of the timing of generating the firing pulse and various data for operating the switching circuit 18 by the drive circuit 44.

Note that the power supply device 10 is a power supply device for an electromagnetic chuck that applies an excitation voltage to the excitation coil only during a period when the magnetic material is to be attracted to the work surface, and does not demagnetize the magnetic material when operation is stopped. When used, the switching circuit 18 and the driving circuit 44 are unnecessary. Also power supply
When using 10 as a power supply for a demagnetizer, the switch 32 may not be used.

When the power switch is turned on, the phase detection circuit 26
A zero-cross signal shown in FIG. 2C having a frequency and a phase corresponding to the frequency of the alternating current supplied to 14 is generated.

After clearing the counter 38, the arithmetic circuit 28 waits for the supply of a zero-cross signal, as shown in FIG. 3 (A). When the zero-cross signal is supplied, the arithmetic circuit
28 operates the counter 38. This allows the counter
38 calculates the clock signal supplied from the clock signal generation circuit 36. When the next zero-cross signal is supplied to the arithmetic circuit 28, the arithmetic circuit 28 stops the operation of the counter 38, takes in the calculated value of the counter 38, determines the AC frequency input to the terminal 14, The data in the frequency storage unit in the memory 40 is updated to data according to the result of the determination.

The determination of the frequency in the arithmetic circuit 28 is performed, for example, by determining the count value read from the counter 38 as a clock signal generating circuit 36.
The frequency can be set to 50 Hz when the frequency is equal to or higher than a specific value determined by the frequency of the clock signal generated in the above, and to 60 Hz when the frequency is lower than the specific value.

Instead of determining the AC frequency input to the terminal 14 by the arithmetic circuit 28, a manually operated switch for specifying the AC frequency input to the terminal 14 may be provided.

Thereafter, the arithmetic circuit 28 executes a start process for starting the operation of the electromagnet applied device when the switch 30 is depressed, and a stop process for stopping the operation of the electromagnet applied device when the switch 32 is depressed. Execute. The start processing and the stop processing differ depending on the type of the electromagnet application device using the power supply device.

Although the power supply device 10 is different depending on which power supply device for the electromagnet applied device, the arithmetic circuit 28 performs the frequency conversion with respect to the zero-cross signal supplied from the phase detection circuit 26 during the start processing or the stop processing. FIG. 2 (D) in which the phase is shifted by a value T determined by the determination result and the value set in the setting device 34.
Is output to the firing pulse generation circuit 42 every time a zero-cross signal is input.

As the phase shift value T of the pulse signal with respect to the zero-cross signal output from the phase detection circuit 26, for example, a phase shift value for each combination of a voltage value that can be set in the setting device 34 and an AC frequency is stored in a memory. , Can be obtained by reading out a predetermined phase shift value to the arithmetic circuit 28 every time the zero-cross signal is supplied to the arithmetic circuit 28. As the phase shift value T, a coefficient for obtaining a predetermined phase value is stored in the memory 40 for each combination of a voltage value that can be set in the setting device 34 and an AC frequency. A predetermined coefficient can be read out to the arithmetic circuit 28 each time it is supplied to the arithmetic circuit 28, and a predetermined operation can be executed by the arithmetic circuit 28 to obtain the coefficient.

The arithmetic circuit 28 may be configured to, for example, clear the counter 38 every time a zero-cross signal is input, and generate a pulse signal when the calculated value of the counter 38 matches the phase value T read from the memory 40. .

Each time the pulse signal is supplied from the arithmetic circuit 28, the firing pulse generation circuit 42 outputs a firing pulse having the same phase as the pulse signal to the control rectifier 20. This causes the control rectifier element 20 to perform a phase shift with respect to the alternating current input to the terminal 14 by a value corresponding to the combination of the voltage value set in the setting unit 34 and the frequency of the alternating current. The AC shown in FIG. 2 (E) is supplied to 16, and a voltage shown in FIG. 2 (F) is obtained between the output terminals of the rectifier circuit 16 and applied to the exciting coil 12. Therefore, the excitation voltage applied to the excitation coil 12 has a value corresponding to a combination of the voltage value set in the setting device 34 and the AC frequency.

Next, start processing, stop processing, and demagnetization processing by the arithmetic circuit 28 when the power supply device 10 is used as a power supply device for an electromagnetic chuck will be described.

I. Start Process When the power supply device 10 is used as a power supply device for an electromagnetic chuck that does not use a permanent magnet, the arithmetic circuit 28 is configured as shown in FIG.
As shown in the figure, a pulse signal having a predetermined phase difference with respect to the alternating current input to the terminal 14 is fired every time a zero-cross signal is input from the time when the switch 30 is pressed down to the time when the switch 32 is pressed down. It is supplied to the pulse generation circuit 42. At the same time, the arithmetic circuit 28 outputs a switching signal for controlling the switching circuit 18 so that the exciting coil 12 is in the positive excitation state.
It is supplied to the switching circuit 18 via 44. As a result, the firing pulse generating circuit 42 outputs a firing pulse to the control rectifier 20 every time a pulse signal is input from the arithmetic circuit 28. As a result, the work surface for attracting the magnetic material is in the excited state.

When the power supply device 10 is used as a power supply device for an electromagnetic chuck that uses a switchable permanent magnet but does not use a non-switchable permanent magnet, the arithmetic circuit 28 operates as shown in FIG. As a result, a pulse signal having a predetermined phase difference with respect to the alternating current input to the terminal 14 is supplied to the ignition pulse generating circuit 42 for a certain period of time. At the same time,
The arithmetic circuit 28 supplies a switching signal for controlling the switching circuit 18 to the switching circuit 18 via the drive circuit 44 so that the excitation coil 12 is in the positive excitation state. As a result, the switchable permanent magnet is magnetized, so that the work surface for attracting the magnetic material is in an excited state.

When the power supply device 10 is used as a power supply device for an electromagnetic chuck using a switchable permanent magnet and a non-switchable permanent magnet, the operation circuit 28 switches the switch 30 down as shown in FIG. 3 (C). Thereby, a pulse signal having a predetermined phase difference with respect to the alternating current input to the terminal 14 is supplied to the ignition pulse generation circuit 42 for a certain period of time, and the switching circuit 18 is controlled so that the excitation coil 12 is in a positive excitation state. The switching signal is supplied to the switching circuit 18 via the driving circuit 44. As a result,
Since the switchable permanent magnet is magnetized in the same manner as the non-switchable permanent magnet, the work surface for attracting the magnetic material is in an excited state.

II.Stop processing When the power supply device 10 is used as a power supply device for an electromagnetic chuck that does not use a permanent magnet, the arithmetic circuit 28 supplies a pulse signal to the ignition pulse generation circuit 42 when the switch 32 is depressed. Stop. As a result, the ignition pulse is not supplied to the control rectifier 20 and the excitation voltage is not applied to the excitation coil 12, so that the work surface for attracting the magnetic material is in a non-excitation state.

When the power supply device 10 is used as a power supply device for an electromagnetic chuck that uses a switchable permanent magnet but does not use a non-switchable permanent magnet, the arithmetic circuit 28 operates by switching the switch 32 down. The demagnetization process for degaussing is performed. As a result, the switchable permanent magnet is demagnetized, and the work surface is de-energized. The degaussing process in this case is the same as the degaussing process for the magnetic material described later.
Therefore, in this case, the switchable permanent magnet is demagnetized, and the magnetic material adsorbed on the work surface is simultaneously demagnetized. However, the demagnetization processing of the magnetic body may be executed after the demagnetization processing of the switchable permanent magnet is executed.

When the power supply device 10 is used as a power supply device for an electromagnetic chuck using a switchable permanent magnet and a non-switchable permanent magnet, the arithmetic circuit 28 reversely excites the excitation coil 12 due to the switch 32 being pressed down. In order to supply a pulse signal having a predetermined phase difference with respect to the alternating current input to the terminal 14 to the ignition pulse generation circuit 42 for a predetermined time,
A switching signal for controlling the switching circuit 18 to be in the reverse excitation state of 12 is supplied to the switching circuit 18 via the driving circuit 44. As a result, the switchable permanent magnet is magnetized reversely to the non-switchable permanent magnet, so that the work surface for attracting the magnetic material is kept in the non-excited state.

III. Demagnetization Process The power supply device 10 can execute a demagnetization process for demagnetizing the magnetic material adsorbed on the work surface of the electromagnetic chuck after the termination process is completed. This demagnetization processing is performed by an arithmetic circuit
28 is done by performing one of the following:

(A) As shown in FIG. 3 (D) or FIG. 3 (E),
A pulse signal having a predetermined phase is generated from the arithmetic circuit 28 to generate a firing pulse which generates a gradually attenuating excitation voltage.
A switching signal for controlling the switching circuit 18 is output from the arithmetic circuit 28 to the switching circuit 18 via the driving circuit 44 so that the exciting coil 12 repeats the forward excitation state and the reverse excitation state at predetermined time intervals, while outputting the same to the switching circuit 18. Output.

(B) As shown in FIG. 3 (D) or FIG. 3 (E),
The switching circuit 18 outputs a pulse signal having a predetermined phase from the arithmetic circuit 28 to the firing pulse generation circuit 44, and the switching circuit 18 causes the excitation coil 12 to repeat the forward excitation state and the reverse excitation state at gradually decreasing time intervals. Arithmetic circuit for switching signal to control
The signal is output from 28 to the switching circuit 18 via the driving circuit 44.

(C) As shown in FIG. 3 (F), a pulse signal having a predetermined phase is output from the arithmetic circuit 28 to the ignition pulse generation circuit 44 and switched to keep the excitation coil in the reverse excitation state for a predetermined time. A switching signal for controlling the circuit 18 is output from the arithmetic circuit 28 to the switching circuit 18 via the drive circuit 44.

(D) As shown in FIG. 3 (D) or FIG. 3 (E),
A pulse signal having a predetermined phase is output from the arithmetic circuit 28 to the ignition pulse generating circuit 44, and a switching signal for controlling the switching circuit 18 so that the exciting coil 12 is in the reverse excitation state is output from the arithmetic circuit 28 for a predetermined time. Switching circuit via drive circuit 44
18 and then further output a pulse signal having a predetermined phase from the arithmetic circuit 28 to the ignition pulse generating circuit 44 to generate a gradually attenuating excitation voltage, and the exciting coil 12 is in a state opposite to the positive excitation state. A switching signal for controlling the switching circuit 18 so as to repeat the excitation state at predetermined time intervals is output from the arithmetic circuit 28 to the switching circuit 18 via the drive circuit 44.

(E) As shown in FIG. 3 (D) or FIG. 3 (E),
A pulse signal having a predetermined phase is supplied from the arithmetic circuit 28 to the ignition pulse generation circuit 44, and the switching circuit 18 is configured to switch the polarity of the excitation voltage applied to the excitation coil 12.
And a switching signal for controlling the excitation coil 12 is output from the arithmetic circuit 28 to the ignition pulse generating circuit 44.
Outputs a switching signal for controlling the switching circuit 18 from the arithmetic circuit 28 to the switching circuit 18 via the drive circuit 44 so that the forward excitation state and the reverse excitation state are repeated at gradually decreasing time intervals.

The demagnetization processing of the magnetic material can be performed after the termination processing is completed. However, instead of this, a switch for instructing the start of the degaussing process may be provided, and the degaussing process may be performed when the switch is depressed.

When the power supply 10 is used as a power supply for a demagnetizer for demagnetizing a magnetic material, the arithmetic circuit 28 first clears the counter 38 when the power is turned on, as shown in FIG. 3 (G). Then, the count 38 is activated by the supply of the zero-cross signal, and then the operation of the counter 38 is stopped by the supply of the next zero-cross signal. The frequency of the alternating current to be performed is determined, and the data in the frequency storage unit in the memory 40 is updated to data according to the result of the determination.

Thereafter, the arithmetic circuit 28 executes a degaussing process when the start command switch 30 is depressed. The degaussing process at this time may be performed by one of the above-mentioned (a) to (e), preferably (a) or (b).

Operation circuit during start processing, stop processing, and degaussing processing
The phase difference T between the pulse signal supplied from 28 to the ignition pulse generation circuit 42 and the alternating current input to the terminal 14 is the difference between the frequency of the alternating current input to the terminal 14 and the set voltage value set in the setting unit 34. It is preferable to set the value according to the combination. However, the phase difference T between the pulse signal generated during any one of the start processing, the stop processing, and the demagnetization processing and the AC input to the terminal 14 is input to the terminal 14, The phase difference T between the pulse signal generated during other processing and the alternating current input to the terminal 14 may be a constant value determined by the power supply 10 as a value according to the combination with the set voltage value set to 34. .

[Brief description of the drawings]

FIG. 1 is a block diagram of an electric circuit showing one embodiment of a power supply device of the present invention, FIG. 2 is a diagram showing a waveform of an electric signal, FIG. 3 (A), FIG. 3 (B), FIG. (C), FIG. 3 (D),
FIGS. 3 (E), 3 (F), and 3 (G) are diagrams for explaining the operation of the power supply device of the present invention. 10 ... power supply device, 12 ... excitation coil, 14 ... AC input terminal, 16 ... rectifier circuit, 18 ... switching circuit, 20 ... control rectifier element, 22 ... control circuit, 24 ... transformer, 26 ... Phase detection circuit, 28 ... Calculation circuit, 30 ... Switch for operation start command, 32 ... Switch for operation stop command, 34 ...
Setting device for excitation voltage, 36 ... Clock signal generation circuit,
38: Counter, 42: Firing pulse generation circuit, 44: Drive circuit.

Claims (13)

(57) [Claims] 1. A power supply device for applying an electric excitation signal for setting an excitation coil of an electromagnet applied device to a positive excitation state or a reverse excitation state, and rectifies an alternating current to generate an electric excitation signal. Means for generating excitation signal comprising a control rectifier for adjusting the value of the excitation signal,
Frequency signal generating means for generating an electric signal specifying the frequency of the alternating current, based on the output signal of the frequency signal generating means, to generate a pulse signal having a phase corresponding to the output signal of the frequency signal generating means, Control means for outputting the pulse signal to the control rectifier as a control signal; and selectively switching the polarity of the excitation signal applied to the excitation coil so as to selectively keep the excitation coil in a positive excitation state or a reverse excitation state. Switching means, and instructing means for instructing the start of operation of the electromagnet applied equipment or instructing means for instructing start and stop of the operation of the electromagnet applied equipment, wherein the control means is capable of starting or stopping the operation by the instructing means. In response to the instruction, the pulse signal and a switching signal for controlling the switching means are generated to keep the excitation coil in a predetermined excitation state. Comprising a processing circuit, a power supply device electromagnet application equipment. 2. The instructing means is means for instructing start and stop of the operation of the electromagnet applied device, and the processing circuit is configured to set the excitation coil to a predetermined state in response to an instruction to start the operation by the instructing means. 2. The power supply device according to claim 1, wherein the power supply device generates the pulse signal and a switching signal for controlling the switching unit so as to be in the time-positive excitation state. 3. The instructing means is means for instructing start and stop of the operation of the electromagnet applied device, and the processing circuit comprises:
Generating a pulse signal for generating an excitation signal that gradually attenuates, and a switching signal for controlling the switching unit so that the excitation coil repeats a positive excitation state and a reverse excitation state at predetermined time intervals, The power supply device according to claim 1. 4. The instructing means is means for instructing start and stop of the operation of the electromagnet applied device, and the processing circuit is configured to, after the instructing means instruct the operation stop, by the instructing means.
2. The processing circuit according to claim 1, further comprising a processing circuit that generates the pulse signal and a switching signal that controls the switching unit so that the exciting coil repeats a forward excitation state and a reverse excitation state at gradually decreasing time intervals. 3. Power supply. 5. The instructing means is means for instructing start and stop of the operation of the electromagnet applied device, and the processing circuit reverses the exciting coil for a predetermined time after the instructing operation is instructed by the instructing means. 2. The power supply device according to claim 1, further comprising a processing circuit for generating said pulse signal and a switching signal for controlling said switching means so as to be in an excited state. 6. The instruction means is means for instructing start and stop of the operation of the electromagnet applied device, and the processing circuit is configured to, after the instruction means instructs the stop of the operation,
The pulse signal and a switching signal for controlling the switching means so that the excitation coil is in a reverse excitation state for a predetermined time, and then further, the pulse signal for generating an excitation signal that gradually attenuates, 2. The power supply device according to claim 1, further comprising a processing circuit for generating a switching signal for controlling said switching means so that said excitation coil repeats a forward excitation state and a reverse excitation state at predetermined time intervals. 7. The instructing means is means for instructing start and stop of the operation of the electromagnet applied device, and the processing circuit comprises:
The pulse signal and a switching signal for controlling the switching means to switch the polarity of the excitation signal applied to the excitation coil are generated for a predetermined time, and then the pulse signal and the excitation coil are in a positive excitation state. 2. The power supply device according to claim 1, further comprising a processing circuit for generating a switching signal for controlling the switching means so as to repeat the reverse excitation state at gradually decreasing time intervals. 8. The instructing means is means for instructing the start of the operation of the electromagnet applied device, and the processing circuit generates an excitation signal which attenuates gradually after the instructing means instructs the start of the operation. 2. A processing circuit according to claim 1, further comprising a processing circuit for generating the pulse signal for causing the excitation coil and a switching signal for controlling the switching unit such that the excitation coil repeats the positive excitation state and the reverse excitation state at predetermined time intervals. The power supply as described. 9. The instructing means is means for instructing the start of operation of the electromagnet-applied device, and the processing circuit is configured to execute the pulse signal and the exciting coil after the instructing start is instructed by the instructing means. 2. The power supply device according to claim 1, further comprising: a processing circuit for generating a switching signal for controlling said switching means so as to repeat the forward excitation state and the reverse excitation state at gradually decreasing time intervals. 10. The power supply device according to claim 1, wherein said frequency signal generating means includes a switch for specifying the frequency of said alternating current. 11. The frequency signal generating means includes a phase detector that outputs a signal when the alternating current has a predetermined phase angle,
The power supply device according to any one of claims 1 to 9, wherein the processing circuit determines the frequency of the alternating current based on an output signal of the phase detection unit. 12. The apparatus according to claim 12, further comprising: means for setting a value of an excitation signal applied to said excitation coil, wherein said processing circuit sets the value of said excitation signal based on a value set by said setting means and an output signal of said frequency signal generation means. Generating the pulse signal having a phase corresponding to a combination of the value set by the setting means and the output signal of the frequency signal generating means, and outputting the pulse signal as a control signal to the control rectifier. Item (1)
The power supply device according to any one of (1) to (11). 13. The processing circuit according to claim 1, wherein the processing circuit generates the pulse signal from when the start of the operation is instructed by the instructing means until the stop is instructed. A power supply according to claim 1.