RU2196719C2 - Device to protect lift electric motors from overloads and abnormal states - Google Patents

Abstract

FIELD: lifts and elevators; protection devices. SUBSTANCE: invention relates to facilities aimed at protection of lift electric motors from thermal overloads and abnormal operating conditions. Said device has winch electric motor control unit with high speed switch unit and slow speed change-over unity and also time relay connected through power amplifier with actuator. Device incorporates also lift cabin door electric motor control unit, coincidence circuit and accurate stop unit. Time relay is adjustable in delay. In operation time of lift winch motor energized state at slow and high speeds is monitored and time of energized state of lift cabin door motor. If one of monitored time parameters exceeds preset value, lift control circuit is deenergized. Device features enlarged operating capabilities and provides protection of electric motor of lift winch high speed and electric motor of lift cabin door. EFFECT: provision of protection of lift motors at reduced supply voltage and mechanical overloads. 2 dwg

Description

 The invention relates to electrical engineering, and specifically to devices for protecting drive electric motors of elevators from thermal overloads and a number of abnormal operating modes, and can be used for elevators equipped with both single-speed and two-speed asynchronous electric motors, as well as drives with DC motors.

 Known devices for protecting electric motors of an elevator from overloads and abnormal conditions according to as 1320159, a.s. 1074795, according to which the possibility of motor overloads in abnormal conditions is judged by information on the voltage at the zero points of the transformer and star of the stator winding of the electric motor or by a signal from a temperature sensor built into the motor.

 The disadvantages of the known devices are their lack of versatility, in particular, they do not provide protection for the electric drives of the elevator at lower voltage, mechanical overload of the cab, etc.

 As a prototype, a device was selected according to A.S. 1212909. The device includes a winch electric motor control unit, including a low-speed transition unit, as well as a time relay connected to one of the devices of the device. The output of the time relay is connected to the winch motor control unit. In the prototype device, the operating time of the electric motor at low speed is measured, and if it exceeds the set value, the elevator control circuit is turned off.

 The main disadvantage of the prototype device is that the winch motor is not protected during high speed driving, for example, during overloads resulting from phase failure, when the cab or counterweight is jammed, etc. In addition, the known device does not provide protection for the drive motor elevator car doors in abnormal (abnormal) situations.

 In the inventive device for protecting the elevator electric motors from overloads and abnormal conditions, including a winch electric motor control unit comprising a high-speed power unit and a low-speed transition unit, a time relay, the output of which is connected via a power amplifier to an actuating element, a cabin electric motor control unit is introduced the elevator, the coincidence circuit and the exact stop block, while the time relay is made with a tunable time delay, its first, second and third inputs are configured The time arms are connected respectively to the output of the switching unit at high speed, the first output of the low-speed switching unit and the first output of the cabin motor control unit, the fifth potential relay reset input is connected via a match circuit to the output of the winch motor control unit and the second output of the door motor control unit cabins, and the fourth and sixth inputs of the pulse reset of the time relay are connected to the second output of the low-speed switching unit and the exact stop unit.

 In the inventive device for protecting the electric motors of the elevator, the times of the on state of the electric motor of the elevator winch at low and high speeds are controlled, as well as the time of the on-state of the electric motor for driving the doors of the elevator car. If one of the monitored times exceeds the set values, the elevator control circuit is disabled. Thanks to the specified algorithm for protecting the electric motors of the elevator, the claimed device, in comparison with the prototype, provides protection for the electric motor of the elevator winch at high speed, as well as the protection of the electric motor for driving the doors of the elevator car. In addition, the inventive device provides protection for the electric motors of the elevator while lowering the supply voltage, with mechanical overload, etc.

 Comparative analysis with the prototype allows us to conclude that the inventive device for protecting the elevator electric motors from overloads and abnormal conditions contains new blocks and connections, due to which the inventive device has additional positive properties.

 Thus, the claimed device meets the criterion of "novelty." The drawings show: FIG. 1 is a block diagram of a device; figure 2 is a diagram explaining a specific implementation of the blocks of the device.

 The device (Fig. 1) for protecting the elevator electric motors from overloads comprises a winch motor control unit 1, comprising a winch motor control unit 2 for high speed and a low speed switching unit 3, as well as an elevator car electric motor control unit 4, a timer 5 with adjustable shutter speeds time, coincidence circuit 6, block 7 exact stop, power amplifier 8, the actuator 9.

 In this case, the first, second and third inputs of the adjustment of the time delay of the time relay 5 are connected respectively to the output of the switching unit 2 at high speed, the first output of the low speed switching unit 3 and the first output of the elevator car electric motor control unit 4. The fifth input of the potential reset of the time relay 5 through the coincidence circuit 6 is connected to the output of the winch motor control unit 1 and the second output of the cabin door motor control unit 4. The fourth and sixth inputs of the pulse reset of the time relay 5 are connected respectively to the second output of the low speed switching unit 3 and the exact stop unit 7. The output of the time relay 5 through the power amplifier 8 is connected to the actuator 9.

 The device protects the elevator motors from overloads as follows.

 If the elevator car is on the floor and the car doors are closed, a reset signal is constantly received from the second output of the cabin door motor control unit 4 and the winch motor control unit 1 through the matching circuit 6 to the fifth input of the time relay 5. Time relay 5 is in the "reset" state.

 At the moment of the beginning of the movement of the elevator car from the switching unit 2 to high speed, a signal is received at the first input of the time relay 5, which provides the first value of the time relay 5 settings (the first time setting is selected with a margin relative to the time the car moves between floors in the normal situation). At the same time, the winch motor control unit 1 through the matching circuit 6 removes the reset signal from the fifth input of the time relay 5. In this case, the time relay 5 starts the countdown.

 During the movement of the elevator car when passing the next floor from the block 7 of the exact stop to the sixth input of the time relay 5 receives a reset signal. In this way, the length of the passage between the elevator cabs is controlled. In normal mode, the monitored time is less than the first value of the setpoint of the timer 5 and there is a periodic “zeroing” of the last, i.e. time relay 5 does not have time to operate and the elevator control circuit operates in normal mode.

 When approaching a given floor and switching the engine to low speed from the first output of the low-speed switching unit 3, a signal is supplied to the second input of the time relay 5, which provides the second value of the setpoint of the time relay 5 (the second setpoint value is selected with a margin in relation to the time the cab moves to reduced speed in a normal situation). At the same time, from the second output of the low-speed switching unit 3, a pulse nulling signal is supplied to the fourth input of the time relay 5.

 As a result, from the moment the engine switches to low speed, the countdown of the movement time at a reduced speed begins. In normal mode, the monitored time does not exceed the second value of the time relay 5 settings, the latter does not have time to operate and the elevator control circuit operates in normal mode.

 In emergency situations when driving at high or low speeds, the duration of the monitored time interval exceeds the setting of the timer 5, the latter is triggered and through the power amplifier 8 gives a signal to the actuator 9, which disables the elevator control circuit. Moreover, abnormal situations leading to overload of the winch electric motor can be caused by various reasons, in particular mechanical overload, a decrease in the supply voltage by the disappearance of one of the phases of the supply voltage, etc. These factors lead to a decrease in the rotation speed of the electric motor and an increase in the time of movement of the cab. Similarly, the control circuit is switched off when the cab is landing on catchers and when the cab passes extreme stops.

 The protection of the electric motor drive the door of the cabin works as follows. If the cabin is located on the floor and a signal is received from the control unit 4 of the cabin door motor to open or close the doors, then from the first output of this unit to the third input of the time relay 5 a signal is provided that provides the third value of the time relay 5 setting (the third setting time is selected with a margin in relation to the time of opening (closing) the cabin doors in a normal situation). At the same time, the zeroing signal from the fifth zeroing input of the time relay 5 is removed from the second output of the cabin door electric control unit 4 of the cabin door 5. The countdown starts.

 In the normal mode, the controlled time interval for the engine to open (close) the doors is less than the third value of the setpoint of the time relay 5 and after opening (closing) the doors from the second output of the cab door electric motor control unit 4, a “zeroing” signal is sent to the fifth relay input through coincidence circuit 6 5. In this case, the elevator control circuit operates in normal mode.

 In case of emergency, for example, jamming of doors, low voltage, etc., the duration of the monitored time interval exceeds the value of the third setpoint of the time relay 5 and it trips. As a result, a signal is transmitted to the actuator 9 through the power amplifier 8 and the elevator control circuit is switched off.

 Thus, the device provides protection for the winch electric motors and cabin doors both during overloads due to various reasons and in a number of abnormal conditions.

 The implementation of the individual device blocks is illustrated in FIG. 2.

The exact stop unit 7, the cabin door electric motor control unit 4, the winch electric motor control unit 1, the high speed enable unit 2 and the low speed transfer unit 3 contain resistors 10-14, as well as NC contacts 15, an exact stop relay, 16 and 17 - relay for opening and closing doors of the cabin, 18 - relay for movement, 19 - relay for turning on at high speed, 20 - relay for switching to low speed and, in addition, formers 21-25. The resistors 10-14 are supplied with a supply voltage U _n . At the output of the shapers 21-25, providing the noise immunity of the device, there are logical zero signals (log. 0) with closed contacts 15-20 and a logical unit (log. 1) - with open.

 Matcher 6 is performed on the logic circuit 26 "OR NOT". At the output of the OR-NOT element, a log signal is generated. 1 only when a log is sent to its both inputs. 0.

 The time relay 5 contains a pulse generator 27, a pulse counter 28, a decoder 29, logic circuits "AND" 30-32 and "OR" 33-34, differentiating elements 35-36. The first, second and third inputs of the time relay 5 are the inputs of the time delay adjustment. The fourth and sixth inputs of time relay 5 are pulse inputs, and the fifth input is a potential reset input of time relay 5.

 Time relay 5 operates as follows.

 The main element of the timer 5 is a pulse counter 28, which has two operating modes - "zeroing" and "counting".

 The output of the logic circuit "OR" 34 is connected to the input "reset" of the pulse counter 28. "Zeroing" of the counter occurs at the moments of formation of the pulse or potential signal log. 1 at the output of the OR logic circuit 34 (in the first case, the counter is “reset” for a short time interval, and in the second, it is constantly kept in the “zeroed” state). Pulse signal log. 1 is formed using differentiating elements 35-36 and the logical element "OR" 34 at the moment of formation of the fronts of the pulses (signal transition log. 0 - log. 1) on the fourth or sixth inputs of the time relay 5. Potential signal log. 1 is formed by the logic circuit "OR" 26 and is fed to the fifth input of the time relay 5.

In the absence of a signal a log. 1 at the output of the logic circuit "OR" 34, the pulse counter 28 goes into the "count" mode, and the timer 5 starts the countdown. The contents of the pulse counter 28 increases by one when the next pulse is generated by the pulse generator 27. The decoder 29 converts the output code of the pulse counter into a unitary code. At any time, the signal is a log. 1 is formed only on one of the outputs of the decoder, the number of which is determined by the output code of the counter. The time interval T from the start of the count is:
T = τ • n,
where τ is the period specified by the pulse generator;
n is the decoder output number.

 Logic circuit "And" 31 is connected to the output of decoder 29, corresponding to the first time setting. Logic circuit "And" 32 is connected to the output of decoder 29, corresponding to the second time setting. Logic circuit is connected to the output of decoder 29, corresponding to the third time setting " And "30. The second inputs of the logic circuits" And "31, 32 and 30 are connected respectively to the first, second and third inputs of the time adjustment of the time relay 5. In the case of a signal to the first, second or third inputs of the time relay 5. 1, after the first, second or third predetermined time interval has elapsed, a log signal is generated at the output of the OR circuit 33. 1, initiating the shutdown of the elevator control circuit. In all other cases, a logic signal is generated at the output of the OR circuit 33. 0.

 The interaction of the blocks shown in FIG. 2 is carried out as follows.

 If the elevator car is on the floor and the car doors are closed, then the contacts 15-20 are closed, and the output signals of all formers 21-25 have a log level. 0. In this case, the first, second and third inputs of the adjustment of the time delay of the time relay 5 and the inputs of the logic circuit "OR NOT" 26 signals are sent log.0. In this case, a log signal is sent to the fifth input of the potential reset of the timer 5. 1 and, therefore, the time relay is in the “nullified” state, and its output signal has a log level. 0.

 At the moment of the cab movement beginning, contacts 18 and 19, respectively, the motion relays and the high-speed switching relays open and remain in this state when the cab moves at high speed. In this case, the log signals appear at the outputs of the formers 23-24. 1, and at the output of the logic circuit "OR NOT" 26 - a log. 0. In this case, the time relay starts to count down, and the time delay corresponds to the first value of the time setting.

 In the normal mode, when passing the next floor, terminal 15 of the exact stop relay opens briefly before the end of the time relay 5. The opening of the contact leads to the formation of a pulse front at the sixth input of time relay 5 and, therefore, to its reset. At the same time, a log signal is constantly present at the output of time relay 5. 0.

 In an emergency, contact 15 of the exact stop relay opens after the end of the time relay 5, which leads to the appearance of a log signal. 1 at the output of the time relay 5 and, therefore, to turn off the elevator control circuit.

 When approaching a given floor, contact 19 of the engine enable relay to high speed closes, contact 20 of the engine low speed relay opens, and contact 18 of the motion relay remains open. This leads to the formation of a log signal. 0 at the output of the driver 24 and the signal log. 1 at the output of the shaper 25. In this case, the timer 5 is reset by the front of the pulse at the fourth input and starts the countdown, and the time delay corresponds to the second value of the time setting.

 In normal mode, the contact of the exact stop relay 15 opens before the end of the time relay 5. The opening of the contact leads to the formation of a pulse front at the sixth input of the time relay 5 and, therefore, to its reset. At the same time, a log signal is constantly present at the output of the time relay. 0.

 In an emergency, the contact of the relay of the exact stop 15 opens later than the shutdown of the time relay 5, which leads to the appearance of a log signal. 1 at the output of the time relay and, therefore, to turn off the elevator control circuit.

 When the cabin is stopped and the doors are opened (closed), contact 16 (contact 17) of the door opening (closing) relay opens, and contacts 15, 18-20 are closed. This leads to the formation of a log signal. 1 at the output of the shaper 22. In this case, the timer 5 starts the countdown, and the time delay corresponds to the third value of the time setting.

 In normal mode, pin 16 (pin 17) of the door opening (closing) relay closes before the end of the timer 5 shutter speed, which leads to the formation of a log signal. 1 at the input of the OR-NOT logic circuit 26 and, therefore, to reset the time relay 5. At the same time, the signal log.0 is constantly present at the output of the time relay.

 In an emergency, contact 16 (contact 17) of the door opening (closing) relay closes later than the end of the exposure time relay 5, which leads to the appearance of a log signal. 1 at the output of the time relay and, therefore, to turn off the elevator control circuit.

 Shapers 21-25 are implemented on K249LP1, K561LN2, and RC chips; logic circuits are "OR-NOT" 26, "OR" 33-34, and "I" 30-32 on chips K561LE10 and K561LA9, counter and decoder 28 and 29 - on K561IE8 chips. The differentiating elements 35 and 36 are implemented on RC circuits, and the pulse generator 27 contains an RC generator on a K561LA9 logic chip and a frequency divider on K561IE8 chips.

Claims (1)

 A device for protecting the elevator electric motors from overloads and abnormal conditions, including a winch electric motor control unit, comprising a high-speed switching unit and a low-speed switching unit, a time relay, the output of which is connected through a power amplifier to an actuating element, characterized in that the control unit for the electric motor of the doors of the elevator car, the coincidence circuit and the exact stop unit, while the time relay is made with a tunable time delay, its first, second and third the th input of the time delay settings are connected, respectively, with the output of the switching unit at high speed, the first output of the low-speed switching unit and the first output of the cabin door motor control unit, the potential relay reset input is connected through the matching circuit with the winch motor control unit and the second output the control unit for the electric motor of the door of the cabin, and the inputs of the pulse reset of the time relay are connected to the second output of the low-speed switching unit and the output of the unit is accurately stopped wki.

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