JPH0581517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a safety device for an elevator equipped with means for detecting running due to brake dragging or the like and preventing brake seizure.

[Prior Art] Fig. 5 is a block diagram showing a conventional elevator safety device disclosed in, for example, Japanese Patent Application Laid-open No. 60-228379. In the figure, 1 is an induction motor for driving an elevator car (hereinafter simply 2 is a speed command generating means for generating an elevator speed command, 3 is an actual speed detecting means for detecting the actual speed of the elevator, and 4 is a means for comparing the elevator speed command and the actual speed from both of these means 2 and 3. speed control calculation means for calculating and outputting a torque command for the electric motor 1 based on the deviation of the
5 is a current command means for generating a current command to an inverter (not shown) for driving the electric motor 1 based on the torque command from the speed control calculation means 4; 6 is a current command generated by the current command means 5; 7 is a speed control calculation output determination means for determining whether the torque command from the speed control calculation means 4 is equal to or greater than a predetermined value; 8 is a torque command by the speed control calculation output determination means 7; 9 is an elapsed time determining means for determining whether or not the determination of a predetermined value or more has continued for a predetermined time or more, and 9 is an abrupt stop that gives an abrupt stop command to the electric motor 1 in response to determination by the elapsed time determining means 8 that the predetermined time or more has elapsed. It is a command output means.

Next, the operation will be explained. During normal elevator operation, the speed control calculation means 4 generates a torque command based on the deviation between the speed command generated by the speed command generation means 2 and the actual speed of the electric motor 1 detected by the actual speed detection means 3. is calculated, and a current command based on this torque command is given to the inverter for driving the electric motor 1 by the current command means 5, and the operation of the electric motor 1 is controlled by this current.

If the elevator runs with the brakes on (hereinafter referred to as running with brake dragging), the desired torque of the electric motor 1 will need to be increased by the amount of torque caused by the brakes. Therefore, the torque command calculated by the speed control calculation means 4 also becomes larger than during normal operation. In accordance with this increase in torque, the current command from the current command means 5 also increases, but since the upper limit value is specified by the current command limit means 6, it does not increase any further, and the electric motor 1 maintains the current of this upper limit value. energized. On the other hand, when the torque command exceeds a predetermined constant value (acceleration torque equivalent value during normal operation), the speed control calculation output determination means 7 operates, and when this continues for a predetermined time or more, the elapsed time determination means 8 operates, Sudden stop command output means 9
outputs a sudden stop command to bring the elevator to a sudden stop, preventing accidents such as brake seizure.

[Problems to be solved by the invention] Since the conventional elevator safety device is configured as described above, running due to brake dragging is effectively detected, but the power supply voltage may drop even during normal running without brake dragging. In this case, the torque that the electric motor 1 can generate decreases, and the actual speed of the elevator lags behind the commanded speed. Therefore, the torque command generated by the speed control calculation means 4 becomes larger than when the power supply is normal and exceeds a predetermined constant value, and the speed control calculation output determination means 7 and the elapsed time determination means 8 operate, causing the sudden stop command output means 9 to suddenly stop. A stop command may be output. The allowable power fluctuation for the elevator is approximately -15%, and it is possible to operate the elevator normally with power fluctuations of this degree, but in this case, as described above, the sudden stop command output means 9
There was a problem with the system malfunctioning.

This invention was made to solve the above-mentioned problems, and although it reliably detects running due to brake drag and stops the elevator, it does not respond to power supply voltage fluctuations within an allowable range. The purpose is to obtain a safety device for elevators.

[Means for Solving the Problems] The elevator safety device according to the present invention adds to the above-mentioned conventional device the elevator speed command or actual output at the time when the speed control calculation output determination means detects the torque command to be equal to or higher than a predetermined value. Elevator speed determining means is newly provided to detect that the speed is below a predetermined value, and the elevator speed determining means detects that the elevator speed is below the predetermined value, and the elapsed time determining means detects the predetermined value of the torque command that is greater than or equal to the predetermined value. When the continuation for a period of time or more is detected, the sudden stop command output means is operated.

[Effect] The torque command during running due to brake dragging exceeds a predetermined constant value at low motor speeds, but the torque command when the power supply voltage decreases suddenly rises above the predetermined constant value at higher motor speeds. In the elevator safety device of the present invention, the speed of the elevator is determined at the time when the speed control calculation output determining means detects a torque command equal to or higher than a predetermined value, and when the speed is equal to or higher than the predetermined value, the torque command is increased due to brake drag. When it is determined that the torque command is increasing, the sudden stop command output means is operated, and when it is less than a predetermined value, it is determined that the torque command is increasing when the power supply voltage decreases, and the sudden stop command output means is not operated.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention. In the figure, 1 is an electric motor for driving an elevator car, 2 is a speed command generating means, and 3 is a block diagram showing the overall configuration of an embodiment of the present invention.
5 is an actual speed detection means, 4 is a speed control calculation means, 5 is a current command means, 6 is a current command limiting means, 7 is a speed control calculation output determination means, and 8 is an elapsed time determination means, all of which are shown in FIG. This is similar to the conventional example. Reference numeral 9 indicates that a predetermined time has elapsed according to the elapsed time determining means 8 and the elevator speed determining means 10 described below
Sudden stop command output means gives a sudden stop command to the electric motor 1 according to the determination result of 10, and 10 indicates whether the elevator speed command is less than a predetermined value at the time when the speed control calculation output determination means 7 detects that the torque command is equal to or more than a predetermined value. This is an elevator speed determining means that detects whether the speed is lower than a predetermined value and outputs a signal to the sudden stop command output means 9 when the speed is below a predetermined value.

Figures 2 to 4 are time charts for explaining the operation of this embodiment. Figure 2 is during normal operation, Figure 3 is when the power supply voltage drops, and Figure 4 is the speed characteristic a and torque when the brake is dragging. The characteristics b are shown respectively, and in the figure, 11 is the speed command generating means 2.
12 is the actual speed detected by the actual speed detection means 3, and 13 is the signal 11, 12.
This is the torque command calculated by the speed control calculation means 4 from .

Next, the operation of this embodiment will be explained with reference to FIGS. 2 to 4. During normal elevator operation, a torque command 13 is calculated by the speed control calculation means 4 from the deviation between the speed command 11 and the actual speed 12 shown in FIG. is applied to the inverter for driving the electric motor 1, and the operation of the electric motor 1 is controlled by this current.

When the elevator is running with brake drag, as shown in Fig. 4, the actual speed 12 lags behind the speed command 11 by a wide margin from the time of startup, and the torque command 13 suddenly increases near the time of startup and exceeds the predetermined value A. , this state continues for more than a certain period of time. That is, since the value of the speed command 11 at the time when the speed control calculation output determining means 7 detects the torque command 13 which is equal to or higher than the predetermined value A is equal to or lower than the predetermined constant value B, the elevator speed determining means 10 detects this. A signal is output to the sudden stop command output means 9. Therefore, if this state continues for a predetermined period of time or more, the elapsed time determining means 8 also operates and outputs a signal to the sudden stop command output means 9, so the sudden stop command output means 9 operates and outputs a stop command to stop the electric motor. 1 to a sudden stop.

On the other hand, when the power supply voltage drops, as shown in FIG. Actual speed 1
2 lags behind the speed command 11, and the torque command 13 also rapidly increases and exceeds the predetermined value A at this point.
Therefore, the elevator speed command 11 at the time when the torque command 13 exceeds the predetermined value A is the predetermined value B.
As described above, since the elevator speed determination means 10 does not operate and does not output, the sudden stop command output means 9 does not operate.

Note that the elevator speed determination means 10 in this embodiment has an elevator speed command 11 of a predetermined value B.
Although it is determined whether the actual speed 12 of the elevator is equal to or higher than a predetermined value, it may be determined whether the actual speed 12 of the elevator is equal to or higher than a predetermined value.

[Effects of the Invention] As described above, according to the present invention, the sudden stop command output means is operated only when the speed command or actual speed of the elevator is below a predetermined value at the time when the torque command becomes equal to or higher than a predetermined value. Therefore, it does not respond to power supply voltage fluctuations within the allowable range, but
When traveling due to brake dragging, the elevator can be stopped in a reliable manner, and a highly reliable elevator safety device can be obtained and is effective.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, Figs. 2, 3, and 4 are time charts for explaining the operation of this embodiment, and Fig. 5 is a safety diagram of a conventional elevator. FIG. 2 is a block diagram showing the device. In the figure, 1 is an electric motor for driving an elevator car, 2 is a speed command generation means, 3 is an actual speed detection means, 4 is a speed control calculation means, 5 is a current command means,
Reference numeral 6 indicates current command limiting means, 7 indicates speed control calculation output determination means, 8 indicates elapsed time discrimination means, 9 indicates sudden stop command output means, 10 indicates elevator speed determination means, and 11
is the elevator speed command, 12 is the actual speed of the elevator, and 13 is the torque command. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A speed command generation means for generating an elevator speed command, an actual speed detection means for detecting the actual speed of the elevator, and a torque command for the elevator drive motor based on the deviation between the elevator speed command and the actual speed which are the outputs of both of these means. speed control calculation output determining means for detecting that the torque command calculated by the speed control calculation means exceeds a predetermined value;
Elevator speed determination means for detecting that the speed command or actual speed of the elevator at the time when the speed control calculation output determination means detects the torque command being equal to or higher than the predetermined value, and the speed control calculation output determination means elapsed time determining means for determining that the detection of a torque command equal to or higher than a predetermined value continues for a predetermined time or longer; A safety device for an elevator, characterized in that it is provided with a sudden stop command output means for outputting a command to suddenly stop the elevator or stop the elevator at the nearest floor when the continuation of the above torque command for a predetermined time or more is detected.