JPH02106582A - Control device for ac elevator - Google Patents

Abstract

PURPOSE:To ensure safety of operation by a method wherein during the starting of a operation of an elevator, through observation of the ripple component of a brake current, operation of a brake is conformed. CONSTITUTION:A control circuit 11 is provided with a timer means to count a time starting from the generation of a starting command signal at an interior and a current detecting means to detect through a current transformer 14 that the ripple component of a brake current is reduced to a value lower than a given value. When, during the starting of an elevator, a current is in a state in which a current does not entirely flow to a coil 57 due to poor contact of an electromagnetic contactor contact 9a, or when a plunger is not motioned due to abutment of the plunger and a ripple current is not decreased for a given time, a control circuit disconnects excitation of electromagnetic contactors 2 and 9, and following motor control is stopped. This constitution prevents the occurrence of seizure of an electric motor and abnormal wear of a brake lining and enables safety of operation.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a control device for an AC elevator to ensure the safety of the elevator, and in particular, to prevent the electric motor from rotating while the brake is applied. .

[Conventional technology]

FIG. 4 shows an electromagnetic brake assembled integrally with the hoist.

Normally, the brake lever (50) is pushed in the six directions shown in the figure by the spring (51). Therefore, the brake shoe (52) grips the brake wheel (53) and stops its rotation. The brake wheel (53) is fixed to a rotating shaft (54) that is directly connected to the electric motor, and stops the rotation of the electric motor and, by extension, the elevator.

Further, the L-shaped cam (55) rotates in the direction B in the figure as the brake lever (50) moves in the A direction,
The plunger (56) is being pushed up.

When power is supplied to the brake coil (57), the plunger (56) is attracted and moves downward. Along with this lowering, the cam (55) is rotated in the direction C in the figure, and the brake lever (50) is rotated in the direction shown in the figure against the force of the spring (51). With this rotation, the brake shoe (52) releases the brake wheel (53). This release causes the rotation axis (5
4) is driven by an electric motor to move the elevator up and down. Here, in the figure, X is the □ air gap of the plunger magnetic circuit, and when the plunger (56) is attracted, the inductance increases.

A conventional example of a control device using the elevator brake will be described with reference to FIG. In the figure, (1) is a three-phase AC power supply, (2) is an electromagnetic contactor that opens and closes the electrical path from the AC power supply (1), and (2a) is its normally open contact. (3) is an electric motor drive circuit composed of a thyristor or transistor, etc., and (4) is an electric motor driven by this drive circuit (3), which drives the elevator up and down by rotating the rotating shaft (54). be.

(9) is an electric contactor 61 that supplies power (10) to the brake coil (57), and (9a) is its normally open contact.

(11) is actuated by the closing of the start command contact (12) to energize the electric Efl contactors (2) and (9);
A control circuit, V, which operates the drive circuit (3) is a control power source.

(60) is a tether connected to the rotating shaft (54), and the main rope (61) is wound around it to drive the heel (62) and counterweight (63) up and down in a hanging manner.

Next, regarding the operation, when a call occurs in the elevator, the start command contact (12) closes and the control circuit (11
) is activated to energize the electromagnetic contactors (2) and (9). As a result, the contacts (2a) and (9a) are respectively closed and power is supplied to the drive circuit (3), and the brake coil (57) is also energized by the power source (IO). In addition, an operation command is sent to the drive circuit (3) at the moment when current flows through the brake coil (57) and the plunger (56) is attracted and the brake wheel (53) is released.
Electric power is supplied to the electric motor m(4) to generate rotational torque. This rotational torque causes the heel (62) to move up and down smoothly.

[Problems to be Solved by the Invention] Since the conventional AC elevator control device is configured as described above, when the brake does not release due to poor contact of the electromagnetic contactor or warping of the plunger, the electric motor When power is supplied, the electric motor tries to rotate with the brake applied, so a large current flows through the Den III machine, causing the electric motor to burn out, or if you continue to drive with the brake applied, the brake lining will wear abnormally and the brake will stop working. It is dangerous as it may become ineffective.

This invention was made to solve the above problems, and it is necessary to confirm that current is flowing through the coil and at the same time confirm that the plunger has actually operated based on changes in the ripple of this current. The purpose of the present invention is to obtain a control device for an AC elevator that allows continuous operation of the elevator safely.

(Means for Solving the Problems) The control device for an AC elevator according to the present invention generates a braking force by deenergizing a brake coil to stop the elevator, and also generates a direct current containing an AC component by a starting command signal. A brake that applies a voltage to energize the brake coil to release the braking force, a current detection means that detects when the current flux/numerical component of the brake coil becomes less than a predetermined value, and a current detection means that issues the start command signal. and a timer means for counting a predetermined time period larger than the normal detection time limit of the current detection means after the TL flow detection means is detected; and a failure detection means that is activated when the TL flow detection means does not perform a detection operation within the predetermined time period. be.

(Function) In the AC elevator control device of the present invention, the ripple component of the brake current is detected by the current detection means and the timer means, and both the flow of current to the brake coil and the operation of the plunger are observed. and check the operation of the brakes.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1, in which the same parts as in FIG. 6 are denoted by the same reference numerals. In FIG. 1, (13) is a DC power supply device that rectifies AC voltage and supplies DC voltage containing an AC component to the brake coil (57), and (14) is 'W! , shows a current transformer as a current detector, and the control circuit (11) for manually controlling the detected current by this current detector (14) has the configuration shown in FIG.

In Fig. 2, (20) is a rectifier that rectifies the ripple component of the current detected by the current transformer (14), and (30) is a rectifier that outputs a signal when this ripple component is less than a predetermined value and H1 is greater than a predetermined value. The comparator (31) is a timer counter that counts the time limit after the activation command signal is generated and generates an L signal when the count ends.
(32) shows an AND circuit, (33) shows an OR circuit, current transformer (14), rectifier (20), comparator (30)
The AND circuit (32) constitutes a current detection means for detecting that the ripple component of the brake coil current has become below a predetermined value, and the OR circuit (33) detects the current within a predetermined time limit of the timer counter (31). A failure detection means is configured to operate when the means fails to perform a detection operation.

Generally, the inductance of a brake coil is small when the plunger is pushed up by a spring and the air gap is large, and becomes large when the air gap is small when the plunger is attracted.

Therefore, by applying a DC voltage containing an AC component to the coil and observing the ripple component of the current flowing through the coil, it is possible to determine whether or not the plunger is attracted.The present invention is based on this operating principle.

Next, the operation of the embodiment will be explained. First, when a call occurs in the elevator, the start command contact (12) is closed, and the electric lin contactors (2) and (9) are excited by calculations by the CPU in the control circuit, and the contact (2a) is activated.

(9a) is closed and the drive circuit (3) and control circuit (11)
At the same time, a DC power supply (13) containing an AC component is connected to the brake coil (57). Next, current begins to flow to the brake, and the control circuit (11) receives manual input, and the CPU in the circuit confirms that current has flowed to the brake coil.Furthermore, the coil is energized, the plunger operates, and the brake is released. An operation command is sent to the drive circuit (3) at the timing when the motor is turned on, and power is supplied to generate rotational torque to the motor, and the motor starts and the car starts smoothly.

On the other hand, when the coil is energized and the plunger operates,
The ripple component of the coil current decreases and this change is taken into the control circuit (3), and the CPU in the circuit confirms that the brake has been released and continues subsequent control.

In the unlikely event that the plunger does not operate due to poor contact of the electromagnetic contactor contact (9a) or warping of the plunger, no current will flow through the coil or the ripple current will decrease within a predetermined period of time. Since this is not taken into the control circuit (3), the CPU in the circuit determines that there is an abnormality and cuts off the excitation 61 of the electromagnetic contactors (2) and (9), stopping further motor control.

Hereinafter, the operation related to the configuration shown in FIG. 2 will be explained with reference to FIG. 3. Here, time 0 is the time when the activation command signal is generated. Current begins to flow to the brake after a predetermined delay time from the activation command signal, but before the plunger is attracted, the inductance of the coil is small, so the ripple current is large, and when the plunger is attracted, the inductance of the coil increases, causing a ripple. Current decreases. Therefore, the output (a) of the rectifier (20) in FIG. 2 becomes as shown in FIG. 3 (a).

On the other hand, the output (b) of the comparator (30) generates a signal by outputting only the section where the ripple current is large before the hub lunger is attracted. Output (c) of timer counter (31)
) starts counting after the activation command signal is generated, and outputs a signal after counting for a predetermined time. The output (d) of the AND circuit (32) generates an H signal from that point on when the plunger is normally sucked, and remains at L when the plunger is not sucked. Therefore, O
The R circuit (output of 33<8) always outputs H during normal operation.
However, if the plunger is not sucked due to some abnormality, the output will generate an L signal when the counter output finishes counting. As a result, when the output (e) of the OR circuit becomes L, the electromagnetic contactor (9) is deenergized, the brake current is cut off, the electromagnetic contactor (2) is also deenergized, and the operation of the elevator is stopped.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reliably check the operation of the brake by detecting the ripple component of the brake current and observing both the current flowing through the coil and the operation of the plunger. As a result, a highly safe and reliable AC elevator control device can be realized.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram showing an embodiment of the present invention, Fig. 2 is a partial internal configuration diagram of the control circuit, Fig. 3 is an operation waveform diagram of each part of Fig. 2, and Fig. 4 is a hoisting machine. FIG. 5 is a configuration diagram of a conventional example corresponding to FIG. 1. In the figure, (12) is a start command contact, (11) is a control circuit,
(57) is a brake coil, (14) is a current transformer (current detector), (20) is a rectifier, (30) is a comparator,
(31) is a timer counter, (32) is an AND circuit, (
33) is an OR circuit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A brake that generates a braking force by deenergizing a brake coil to stop the elevator, and also applies a DC voltage containing an AC component in response to a start command signal to energize the brake coil and release the braking force; Current detection means for detecting that the ripple component of the current in the brake coil has become below a predetermined value, and timer means for counting a predetermined time period larger than the normal detection time period of the current detection means after the activation command signal is issued. . A control device for an AC elevator, comprising failure detection means that operates when the current detection means does not perform a detection operation within the predetermined time period.