JPS63315487A - Lifting electromagnet 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 [Industrial Application Field] The present invention relates to a lifting electromagnet device that uses an electromagnet to attract and transport loads such as steel materials.

[Conventional technology]

The lifting electromagnet device (hereinafter referred to as lifting magnet 7 device) is equipped with a plurality of electromagnets (hereinafter referred to as magnets), and the number of magnets to be excited is changed depending on the amount of steel material to be attracted and transported.

By the way, in a lifting magnet device, it is necessary to control the attraction force (magnetic force) of each magnet in the same way, and for this reason, generally, the excitation current flowing through each magnet is controlled in the same way.

In conventional lifting magnet devices, a power supply device equipped with a constant current control means is provided for each magnet (or so-called selective excitation section), and the excitation current flowing through each magnet is controlled equally (for example, 1574
Publication No. 5, Utility Model Publication No. 57-4052, and Special Publication No. 5
No. 9-24714 III).

In the case of the above-mentioned lifting magnet device, in order to control the excitation of multiple magnets, multiple power supplies are required. We proposed a lifting magnet device (lifting electromagnet device) that can selectively excite multiple magnets using a power supply device.

[Problem that the invention seeks to solve]

By the way, the number of magnets is n1, the internal resistance of the lifting magnet is R1, the control range of the excitation current is l111(
Maximum) ~ In (minimum), the output voltage E of the Cyrisk rectifier is the selected number of lifting magnets n (
(n is a positive integer) is expressed by Equation (11).

E= hrR-n ~ In-R-n - (11, while
There are various sizes of steel materials to be lifted and transported by a lifting magnet device, and in general, the control range of the excitation current required to control the magnetic force of the magnet is approximately 100 to 10%.
It is. Therefore, the actual output voltage of the thyristor rectifier falls within the range shown by equation (2).

■Ugly Also, generally the output voltage control range of thyristor rectifier is 1
00 to about 5%, it is necessary to satisfy the relationship shown in equation (3).

As shown in equation (3), it is necessary that n≦2. In other words, in the case of the "lifting electromagnet device" filed on the same day, the number of lifting magnets is limited to two in order to achieve the above-mentioned necessary excitation current control range.
The above-mentioned required excitation current control range cannot be applied to a lifting magnet device having ~8 lifting magnets.

[Means for solving problems]

In the present invention, a plurality of magnets are connected in series to one voltage side 'a1!1 source device,
It has a selection means for selecting excitation for a plurality of magnets, and calculates the required power supply voltage based on the excitation current to be passed through the magnet, the resistance of the magnet, and the selected number of magnets, and calculates the required power supply voltage based on the required power supply voltage and a predetermined standard. A lifting magnet device having a control means for controlling the output voltage of the voltage controlled power supply device by comparing the voltage with the above voltage is obtained.

〔Example〕

The present invention will be explained below with reference to Examples.

First, referring to FIG. 1, an AC power source (not shown) is connected to a thyristor rectifier 2 via a power transformer l. On the other hand, a plurality of magnets 31 to 3n are connected in series to each other and connected to the thyristor rectifier 2. A plurality of electromagnetic contactors 41 to 4n are connected in series and connected in parallel to magnets 31 to 3n connected in series.

As shown in the figure, the connection points between the electromagnetic contactors and the connection points between the magnets are connected.

When lifting and transporting steel materials using the magnet device configured as described above, the alternating current from the power transformer 1 is passed through the Cyrisk rectifier 2.
The magnets 31 to 3 are converted into direct current as excitation current.
n. At this time, according to the amount of steel to be transported, the electromagnetic contactors 41 to 4n arranged in parallel to each magnet 31 to 3n are opened and closed to selectively control the magnets 31 to 3n to be energized. For example, magnets 31, 32 and 34 (magnet 34 is not shown in Figure 1)
When exciting the electromagnetic contactors 41, 42 . and 44 (magnetic contactor 44 is not shown in FIG. 1) contacts are opened,
The contacts of the other electromagnetic contactors 43, 45 to 4n are closed.

That is, when the contacts of the electromagnetic contactors 43.45 to 4n are closed, the corresponding magnets 33.35 to 3n are substantially short-circuited, and the exciting current is applied to the magnets 33.35 to 3n.
Almost no flow to ~3n, magnetic contactor 43.45~4n
flows through. That is, the magnets 33.35 to 3n are not excited.

Next, the thyristor rectifier 2 is turned on based on a current command from a command circuit (not shown), and the excitation current specified by the current command flows through the magnet.

At this time, as mentioned above, the magnets 31, 32° and 3
4 are connected in series, so each magnet) 31, 3
2. The excitation currents flowing through and 34 have the same value.

On the other hand, the secondary side of the power transformer 1 is connected to the contact 5 of the electromagnetic contactor 5.
The electromagnetic contactor 6 is connected to the SiRisk rectifier 2 through the contact point '6a of the electromagnetic contactor 6, and a predetermined tap is connected to the SiRisk rectifier 2 through the contact '6a of the electromagnetic contactor 6. Further, this lifting magnet device includes a control device consisting of an arithmetic circuit 7 and a comparison circuit 8, and the comparison circuit 8 includes a comparator 8a, a switching transistor 8b, and an electromagnetic contactor 9.

The arithmetic circuit 7 stores the excitation current value to be passed through the magnet (current command (i) from the command circuit), the resistance value of the magnet (
R) and the number of magnets to be selectively excited (n) are input, and the arithmetic circuit 7 calculates the required power supply voltage (V
).

V = i x Rx n...-
-<41 This calculated power supply voltage (V) is input to the comparator 8a. On the other hand, the power supply switching reference voltage (ν
) is input. When the calculated required power supply voltage (V)≧power supply switching reference voltage (V), the comparator 8a outputs a high level signal (H
The switching transistor 8b is turned on by this H signal. switching transistor 8
When b is turned on, the electromagnetic contactor 9 is excited, and its contact 9
a is switched to the terminal 9b side. As a result, the electromagnetic contactor 5 is excited, and its contact 5a is closed (the contact 6a of the electromagnetic contactor 6 is open).

On the other hand, when V<v, the comparator 8a outputs a low level signal (L
signal). As a result, switching transistor 8b is turned off. When the switching transistor 8b is turned off, the excitation of the electromagnetic contactor 9 is stopped, that is, it is in a de-energized state), and as a result, the contact 9a is connected to the terminal 9c.
Switch to the side.

This brings the IIM contactor 5 into a de-energized state and opens the contact 5a. Further, the electromagnetic contactor 6 is excited and the contact 6a is closed.

By the way, 1. To select the tap on the secondary side of the power transformer l,
For example, when the electromagnetic contactor 5 operates, the output voltage range of the thyristor rectifier 2 becomes 100 to 5%, and the electromagnetic contactor 6
operates, the output voltage range of the thyrisk rectifier 2 will be 5
~0.25%. Therefore, the control range of the output voltage of the Sirisk rectifier 2 is 100~0.25%
becomes. That is, the control range of the output voltage of the thyristor rectifier becomes wider, and as a result, it becomes possible to increase the number of magnets.

In addition, although the above-mentioned Example demonstrated the case where one tap was provided on the secondary side of the power transformer l, the structure can be similarly configured even when a plurality of taps are provided.

In order to reduce the number of electromagnetic contactors, for example, as shown in FIG. The electromagnetic contactor 43 may be made to correspond to the magnets 36 and 37.

In other words, one electromagnetic contactor may be arranged in correspondence with a plurality of magnets. Furthermore, as shown in FIG.
The electromagnetic contactor 42 may be made to correspond to the magnets 36 and 37, and the electromagnetic contactor 43 may be made to correspond to the magnets 36 and 37. In other words, a magnet that is constantly excited may be provided, and one electromagnetic contactor may be provided in correspondence with one or more magnets.In this way, various arrangements can be considered for the relationship between the magnet and the electromagnetic contactor. It will be done.

〔Effect of the invention〕

As explained above, according to the lifting magnet device according to the present invention, not only can the currents flowing through a plurality of magnets be equally controlled with one voltage-controlled power supply device, but also the control range of the output voltage of the voltage-side m power supply device is possible. As a result, the number of magnets can be increased.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the lifting magnet device according to the present invention, and FIGS. 2 and 3 are diagrams showing other examples of the connection relationship between the magnet and the electromagnetic contactor, respectively. 1...Power transformer, 2...Thyristor rectifier, 3
1 to 3n...Magnet, 41 to 4n...Magnetic contactor, 5.6...Magnetic contactor, 7...Arithmetic circuit, 8.
...Comparison circuit. Figure 2 1: ``One thing'' Figure 3. -11211”

Claims (1)

[Claims] 1. In a lifting electromagnet device that includes a plurality of electromagnets and uses the electromagnets to attract and transport cargo, the plurality of electromagnets are connected to each other in series and connected to one power supply device, and the plurality of electromagnets are connected in series to one power supply device. a selection means for selecting an electromagnet to be excited from among the electromagnets, and determines the required power supply voltage based on the exciting current to be passed through the electromagnet, the resistance of the electromagnet, and the number of electromagnets, and calculates the required power supply voltage and the selected power supply voltage in advance. A lifting electromagnet device comprising: control means for controlling the output voltage of the power supply device by comparing it with a predetermined reference voltage.