JPH0583473B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Description of the Technical Field] The present invention relates to an elevator door motor protection device that protects a motor that drives an elevator door when an overcurrent flows through the motor.

[Description of prior art]

In an elevator door system, if a foreign object gets caught in the door sill or the opening/closing operation of the door is intentionally obstructed, the door becomes locked and the door is not driven. Overcurrent flows to the motor. If this condition continues for a long time, the motor may burn out or the motor control device may be damaged.

Conventionally, in order to protect the motor and the control device from such overcurrent, a current detection device is provided to detect the overcurrent. When overcurrent is detected, the power supply to the motor is cut off to protect the motor from burning out.

That is, when the current value flowing through the motor exceeds the set current value, the wiring sheath breaker with the tripping coil is tripped by the overcurrent detection signal. By this,
This prevents burnout of the door motor and destruction of switching elements such as transistors that continuously control the power supplied to the door motor. By the way, the set current value is a value that cannot be exceeded during normal door opening/closing operations, and is set to a value that will not be exceeded when the door is locked or when a switching element is broken and a short circuit occurs. In such a conventional configuration, once an overcurrent condition is detected, the elevator will continue to malfunction even if the door lock condition is released, and the elevator will remain idle until maintenance personnel arrive.
This severely impairs service quality.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an elevator door motor protection device that stops a switching element that controls the motor or stops power supply to the motor due to an overcurrent flowing through the door motor.

[Summary of the invention]

The present invention protects the door motor and switching element from overcurrent when the elevator door remains locked, and quickly returns to normal elevator operation when the door is no longer locked.

[Embodiments of the invention]

The present invention will be explained based on an embodiment shown in the drawings.

FIG. 1 is a block diagram showing the configuration of a control device according to the present invention. A three-phase AC power source 10 inputs three-phase AC to a three-phase full-wave rectifier circuit 12 through a wiring sheath breaker 11 with a tripping coil, and undergoes full-wave rectification.
Bridge connected transistors 13, 14, 1
Reference numerals 5 and 16 are for motor control, and the control output thereof is supplied to the door motor 17 to open and close the door. Transistors 13 to 16 are motor control circuit 1
Connected to 8. The motor control circuit 18 includes a control circuit 20 that controls the transistors 13 to 16 in response to a pattern signal from a pattern generation circuit 19, and a base current cutoff circuit 21 that cuts off the base current and stops the operation of the transistors. included.

A detection signal from a current detector 22 that detects the current flowing through the door motor 17 is input to an overcurrent detection circuit 23 having first and second set values. The output signal of the overcurrent detection circuit 23 is sent to the off-delay circuit 24.
The base current is sent to the base current sheath disconnection circuit 21 and the wiring sheath disconnector 11 with a tripping coil.

FIG. 2 shows a specific circuit diagram of the overcurrent detection circuit 23. The mutual connection points of variable resistors 25, 26, 27 that divide the output signal voltage V _I of the current detector 22 are Zener diodes 28, 29 and resistors 30, 3.
1 to the bases of transistors 32 and 33. The collectors of the transistors 32 and 33 are connected to the power supply line 3 through resistors 34 and 35, respectively.
6, and are connected to the wiring sheath disconnector 11 and the off-delay circuit 24 through inverters 37 and 38, respectively.

FIG. 3 shows a specific circuit diagram of the off-delay circuit 24. A signal from overcurrent detection circuit 23 is input to inverter 39 . Variable resistor 40 and resistor 41
The inverter 39 is connected to an inverter 43 via a parallel circuit with a series circuit of a diode 42, and an output of the inverter 43 is connected to the base current cutoff circuit 21. The input of the inverter 43 is grounded via a capacitor 44.

Next, the operation will be explained using FIGS. 1 and 4. When the door is in a locked state during opening/closing, the current value supplied to the door motor 17 becomes the first value shown in FIG.
When the set value _I1 is exceeded, an overcurrent detection signal 23a is outputted from the overcurrent detection circuit 23 and inputted to the off-delay circuit 24. The output signal 24a of the off-delay circuit 24 is outputted and input to the transistor base current cutoff circuit 21. This stops the transistor switching, cuts off the power supply to the motor, and reduces the motor current. As a result, the current value flowing through the motor returns to the first set value I ₁
As a result, the overcurrent detection signal 23a is canceled, but the off-delay circuit 24 operates and the base shearing signal 24a is activated during the preset △t _OFF period.
continues to be output, and transistors 13 to 16 remain turned off. After the Δt _OFF period has elapsed, the interruption of the base current is released, but if the door is still in the locked state, the overcurrent detection signal 23a is output again, and the same operation is repeated. This situation is shown in FIG. When the door is in the _locked state, the door motor 17 is
It is possible to lower the effective value of the voltage supplied to the
Therefore, the current flowing through the door motor is also reduced, and even if the door remains locked for a long time, the door motor can be prevented from burning out. Additionally, once the passenger no longer gets stuck in the door, removes foreign objects, or otherwise intentionally obstructs door operation, and the door is no longer locked, normal door opening/closing operations can be quickly resumed. I can do it. In addition, by changing △t _OFF ,
The effective value of the voltage supplied to the door motor can be varied.

On the other hand, if an overcurrent flows due to destruction of the transistor elements 13 to 16, etc., there is no effect even if the base current is interrupted. In that case, as shown in FIG. 4, the current exceeds the first current setting value I ₁ and further increases, so the second
When the detected current exceeds the set value _I2 , an overcurrent detection signal 23b is output from the overcurrent detection circuit 23, and the wiring sheath breaker 11 with a tripping coil is tripped to protect the circuit. The first current setting value _I1 is set to a value that cannot be exceeded during normal door opening/closing operations, and the second
The current setting value _I2 is set to a value that does not exceed when the door is locked.

The operation will be explained with reference to FIG. The detection signal voltage V _I outputted in comparison with the current supplied to the door motor 17 is divided using variable resistors 25, 26, and 27. The divided voltages V ₁ and V ₂ are the Zener voltages of the Zener diodes 28 and 29, respectively.
When it becomes larger than V ₂₈ and V ₂₉ , transistor 3
A base current flows through 2 and 33. Transistors 32 and 33 turn on, and inverter 3
By setting the inputs of 7 and 38 to ground level,
An overcurrent detection signal is output for each. Therefore, if the resistance values of resistors 25, 26, and 27 are R ₂₅ , R ₂₆ , and R ₂₇ , the divided voltage is v ₁ = R ₂₆ + R ₂₇ / R ₂₅ + R ₂₆ + R ₂₇ V _I v ₂ = R It can be expressed as ₂₇ /R ₂₅ +R ₂₆ +R ₂₇ V _I. The voltage v ₂ exceeds the current setting value I ₁ .
The voltage _dividing resistor value must be adjusted so that the current setting value I ₂ is exceeded so that the voltage V ₁ exceeds V ₂₈ .
By setting R ₂₅ , R ₂₆ , R ₂₇ and Zener voltage values v ₂₈ , v ₂₉ , the necessary overcurrent detection signals 23a, 2
3b can be obtained.

The operation will be explained with reference to FIG. As shown in FIG. 5, during normal door opening/closing operations, the overcurrent detection signal 23a is at a low level, the output of the inverter 39 is at a high level, and the capacitor 44 is charged. The input of the inverter 43 is at a high level, and the output signal 24a of the off-delay circuit 24 is at a low level. Overcurrent detection signal 23a at time A
When the output becomes high level, the output of the inverter 39 becomes low level, and the charge of the capacitor 44 becomes
It is discharged through resistors 40 and 41. Here, the resistance values of resistors 40 and 41 are R ₄₀ , R ₄₁ and capacitor 44
Let the capacity of be C ₄₄ . Due to the discharge of the capacitor 44, the input of the inverter 43 changes from a high level to
change to a lower level. The time △t _ON required for this is △t _ON = 0.7 × C ₄₄ × R ₄₀ × R ₄₁ /R ₄₀ + R ₄₁ . With this delay time, the inverter 43
The output signal 24a changes from a low level to a high level, as shown at point B in FIG. Next, the overcurrent detection signal 23a changes from a high level to a low level as shown at point C in FIG. At this time, the output of the inverter 39 is at a high level, and the capacitor 44 is charged through the resistor 40. The time Δt _OFF required for the input of the inverter 43 to change from a low level to a high level due to this charging is Δt _OFF ≈0.7×C ₄₄ ×R ₄₀ . With this delay time, the output signal 24a of the inverter 43 changes from high level to low level as shown at point D in FIG. Here, the resistance value
If R ₄₀ and resistance value R ₄₁ are set in the relationship R ₄₁ ≪R ₄₀ , △t _ON ≒0.7×C ₄₄ ×R ₄₁ △t _OFF ≒0.7×C ₄₄ ×R ₄₀ , △t _ON ≪△t _OFF . Overcurrent detection signal 23a
is output, the output signal 24a of the off-delay circuit 24 is quickly output, but even if the overcurrent detection signal 23a disappears, the output signal 24a of the off-delay circuit 24 remains output during Δt _OFF . Note that it is clear that Δt _OFF can be varied by changing the resistance value R ₄₀ .

〔Effect of the invention〕

According to the present invention, even if a foreign object gets caught in the door groove during the opening/closing of the elevator door or the door opening/closing operation is intentionally obstructed and the door remains locked, the door motor will not burn out or the switching element will be destroyed. can be prevented. Additionally, foreign objects can be removed without the need for elevator maintenance personnel or intentional obstruction of door operation.
It is possible to quickly return to normal operation, improving serviceability.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the door motor protection device according to the present invention, Fig. 2 is a circuit diagram of the overcurrent detection circuit shown in Fig. 1, Fig. 3 is a circuit diagram of the off-delay circuit shown in Fig. 1, and Fig. 4 is a circuit diagram of the overcurrent detection circuit shown in Fig. 1. A current waveform diagram flowing through the door motor, FIG. 5 is an explanatory diagram of the operation of the off-delay circuit shown in FIG. 3. 10... Three-phase AC power supply, 11... Wiring cutter with tripping coil, 12... Three-phase full-wave rectifier circuit, 13, 14, 15, 16... Transistor,
17...Door motor, 18...Motor control circuit,
21...Base current cutout circuit, 22...Current detector, 23...Overcurrent detection circuit, 24...Off delay circuit.

Claims (1)

[Claims] 1. Compare a current detector that detects the current flowing through the door motor that drives the elevator door, and the detection signal of this current detector with a first set value and a second set value that is larger than the first set value. an overcurrent detection circuit; and a signal is output in response to a first detection signal of the overcurrent detection circuit when the detection signal of the current detector exceeds a first set value, and the first detection signal is turned off. Then, an off-delay circuit whose output signal is turned off after a certain period of time, a motor control circuit which stops driving the door motor based on the output signal of this off-delay circuit, and a motor control circuit that stops driving the door motor when the detection signal of the current detector exceeds a second set value. The second overcurrent detection circuit
A door motor protection device for an elevator, comprising: a cutoff switch that cuts off power supplied to the door motor in accordance with a detection signal of the door motor.