JPH07206308A - Electromagnetic brake device of elevator - Google Patents

Abstract

PURPOSE:To provide an electromagnetic brake device of an elevator, by which burning of a coil is prevented by easily detecting that a switch is gotten stuck and a resistor is short-circuited. CONSTITUTION:An electromagnetic brake device comprises a relay 12 for detecting an electric current flowing through a coil 1 and detecting that the detected electric current exceeds a designated value, and a warning device 15 for giving information to the outside when the detection relay 12 is energized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in electromagnetic brake devices for elevators.

[0002]

2. Description of the Related Art In an electromagnetic brake device for an elevator, as disclosed in, for example, Japanese Utility Model Laid-Open No. 56-40163, a coil and a resistor of the electromagnetic brake are connected in series in order to improve the response time of the electromagnetic brake. In addition, a circuit having a switch that opens and closes according to the position of the plunger is connected in parallel with this resistor. At the time of start-up, the resistor is short-circuited by a switch, the exciting current flowing through the coil rises sharply, and when the plunger reaches a predetermined position, the switch is opened and the resistor is inserted to limit the exciting current to a predetermined value.

[0003]

By the way, in the conventional electromagnetic brake device, there is a problem in that the switch sometimes gets stuck, the resistance is short-circuited, an excessive current flows in the coil, and the coil is burned.

In view of the above-mentioned drawbacks, the present invention can easily detect that the switch is tight and the resistor is short-circuited,
It is an object of the present invention to provide an electromagnetic brake device for an elevator that prevents the coil from being burnt.

[0005]

An object of the present invention is to provide an electromagnetic brake device for an elevator, in which a coil and a resistor are connected in series, and which is excited by a circuit having a switch which opens and closes in parallel with the resistor in accordance with the position of a plunger, This is achieved by providing means for detecting a current flowing through the coil and detecting that the detected current exceeds a predetermined value and means for notifying the outside when the detecting means operates.

[0006]

[Operation] Now, if the switch fails and the resistor is short-circuited,
When the current flowing through the coil increases and exceeds a predetermined value, for example, a failure detection relay operates and an alarm sounds.

As a result, it is found that the brake device has failed, and it is possible to prevent the coil from being burnt out in advance and to prevent accidents due to the brake device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 3 is a schematic diagram of the electromagnetic brake.

In the figure, 1 is a coil, 2 is an arm that rotates about a hinge 3 as a fulcrum, 4 is a shoe fixed to the arm 2, 5 is a drum connected to a hoisting machine (not shown), and 6
Is a spring for pressing the arm 2, 7 is a frame for fixing the coil 1, 8 is a switch attached to the frame 7, and when the electromagnetic brake is released, the contact 8b of the switch 8 is closed, but the electromagnetic brake is excited. Then, the arm 2 is rotated outward, and the contact 8b is opened.

FIG. 1 is an electrical connection diagram of an electromagnetic brake device according to the present invention.

In the figure, P and N are DC power supply terminals and 10
a is a contact of a start command relay (not shown), 11 is a resistor connected in series to the coil 1 of the electromagnetic brake, and the contact 8b of the switch 8 is connected in parallel with the resistor 11. Reference numeral 12 is a failure detection relay that is activated when the current flowing through the coil 1 exceeds a predetermined value, 12a is its a contact, and 13 is an auxiliary relay that stores that the relay 12 is energized. 13a is its a contact, and 14b is the relay 1
A switch for releasing 3 and 15 are alarm devices connected in parallel with the relay 13.

Next, the operation of this embodiment will be described with reference to the time chart of the current flowing through the coil 1 shown in FIG.

Now, when the elevator is started at time t0 in FIG. 2, the contact 10a is closed, and P-10a-8b-12.
A current flows through the -1-N circuit and the current increases as shown by the solid line F1, and when the arm 2 rotates, the switch 8 operates,
The contact 8b opens, and the current is limited by the resistor 11 and becomes the rated current I1.

Next, it is assumed that the switch 8 is so reluctant to operate.

In this case, the current exponentially increases as indicated by the dotted line F2, and when the current reaches the current I2 (time t2), the relay 12 is energized and the current rises to the current I3. When the relay 12 is energized, the contact 12a is closed and the auxiliary relay 13 is energized, self-held via the contact 13a, and the alarm 15 sounds.

The person in charge of the building notices that the electromagnetic brake is abnormal due to this ringing sound, takes corrective action, and pushes the switch 14b to restore the original state.

In this way, when an abnormality occurs in the switch, the alarm is sounded and the manager is notified, so that the coil 1 can be prevented from being burned.

Although the abnormal current of the coil 1 is directly detected by the relay 12 in the above embodiment, the current value may be amplified and detected. Although the alarm device 15 is activated when a failure occurs, it goes without saying that the alarm may be sent to the monitoring center, for example, and the elevator may be stopped at the nearest floor.

[0020]

As described below, according to the present invention, when the current flowing through the coil of the electromagnetic brake exceeds a predetermined value, it is configured to notify the outside, so that burnout of the coil can be prevented. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is an electrical connection diagram of an electromagnetic brake device according to the present invention.

FIG. 2 is a time chart diagram of a current flowing through a coil 1 of an electromagnetic brake device.

FIG. 3 is a schematic configuration diagram of an electromagnetic brake.

[Explanation of symbols]

 1 coil 8 switch 12 relay for detecting fault current 15 alarm device

Claims (1)

[Claims] 1. An electromagnetic brake device for an elevator, wherein a coil and a resistor are connected in series, and a circuit having a switch that opens and closes in parallel with the resistor is excited. ,
An electromagnetic brake device for an elevator, comprising: means for detecting that the detected current exceeds a predetermined value and means for notifying the outside when the detecting means operates.