JP2001292585A - Apparatus for limiting and monitoring revolution of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for limiting and monitoring the revolution of a motor, which can surely detect the condition where a motor cannot be started, also can accurately detect the waiting time until the re-start becomes possible and can reduce the load on an operator. SOLUTION: Whether a motor is driven or not is detected by setting the condition that the temperature of stator winding of a motor be set equal to be ambient temperature as the initial condition, it is recognized that to which condition (cold, hot, very hot, re-drive is impossible) among the setting temperatures to be set step by step between the ambient temperature and to limit temperature the temperature of stator winding of motor corresponds based on the passing time in the continuous operating condition or on the passing time in the stop condition. When it goes into a state where re-drive becomes impossible, an alarm is issued and the waiting time 40, until the re-drive becomes possible, is displayed in the count-down mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for monitoring the number of times of starting of a motor.

[0002]

2. Description of the Related Art In general, a large capacity and high pressure for driving a push-in ventilator (FDF), a primary ventilator (PAF), an induction ventilator (IDF), or a mill for coal pulverization used in a boiler plant. In the motor, the number of consecutive start-ups is limited to prevent the stator winding from burning.

[0003] Therefore, when it becomes impossible to start the next time, it is necessary to wait until the temperature of the stator winding is lowered.

[0004] Such monitoring of the waiting time for cooling has conventionally been carried out.
This has been done by an operator actually measuring and confirming the temperature of the stator windings, or by measuring the cooling time resulting from the motor specifications.

[0005]

However, as described above, when the motor cannot be started, as described above, the operator actually measures the temperature of the stator winding and checks it, or checks the motor specifications. When the resulting cooling time is measured, there is a problem that the measurement result may vary from operator to operator and the operator's burden increases.

The present invention has been made in view of the above circumstances, and when the motor cannot be started, it is possible to reliably detect the state and to accurately grasp the waiting time until the motor can be restarted. It is an object of the present invention to provide a motor start count restriction monitoring device capable of reducing the burden on an operator.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a motor is started from a state in which a temperature of a stator winding of a motor is equal to an ambient temperature.
The number of cold start limits, which indicates how many times the motor can be stopped when the rated speed is reached, restarted immediately, and stopped when the rated speed is reached, is reached. Start the motor from the state equal to the stable temperature, stop when the rated speed is reached, restart immediately and stop when the rated speed is reached. A start count limit monitoring device, which detects whether the motor is started or stopped, with a state where the temperature of the stator winding of the motor is equal to the ambient temperature as an initial state,
Based on the elapsed time in the operation continuation state or the elapsed time in the stop state, the temperature of the stator winding of the motor is set at any one of the set temperatures set in steps from the ambient temperature to the limit temperature. The motor is characterized in that it is configured to recognize whether it is in a state equal to the temperature and to issue an alarm when the restart becomes impossible, and to display a countdown display of a waiting time until the restart becomes possible. The present invention relates to a start-up frequency limit monitoring device.

According to the above means, the following effects can be obtained.

With the state where the temperature of the stator winding of the motor is equal to the ambient temperature as an initial state, it is detected whether the motor has been started or stopped, and the elapsed time in the continuous operation state or the stopped state in the stopped state has been detected. Based on the elapsed time, it is recognized that the temperature of the stator winding of the motor is equal to which of the set temperatures set in steps from the ambient temperature to the limit temperature. When it becomes impossible to start, a warning is issued and the waiting time until the restart becomes possible is displayed as a countdown.

As a result, when the motor cannot be started, there is no need for the operator to actually measure and confirm the temperature of the stator winding or to measure the cooling time resulting from the specification of the motor. In addition, there is no possibility that the measurement results will be varied by the operator, and the burden on the operator will be reduced.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a definition and description of a temperature state of a stator winding of a motor according to an embodiment of the present invention. FIG. 2 is a diagram showing a motor stator according to an embodiment of the present invention. FIG. 3 is a diagram showing a temperature curve of a winding, and FIG. 3 is a diagram showing a state transition flow of a temperature of a stator winding of a motor in an example of an embodiment of the present invention.

As shown in FIG. 1, a state in which the temperature of the stator winding of the motor has reached the ambient temperature after a long time has elapsed since the motor stopped is referred to as "cold". "Hot" means that the temperature is stable when the operation is continued, and "Berry hot" means that the motor that has reached the start limit can be restarted once after the required cooling time has elapsed. "2C1H" is "hot"
The same state as above), and the state in which restarting has been performed once from the belly hot state is defined as “restart impossible”.

Here, the motor is started from a state where the temperature of the stator winding is equal to the ambient temperature (cold), stopped when the rated speed is reached, restarted immediately, and stopped when the rated speed is reached. The number of times the cold start can be performed within the safe range electrically and mechanically is the so-called cold start limit number, and the case where the cold start limit number is 2 is "2C" and the case where it is 3 times Is described as "3C", the motor is started from a state in which the temperature of the stator winding of the motor is equal to the stable temperature when the motor rated operation is continued (hot), stopped when the rated rotation speed is reached, and immediately restarted. The so-called limited number of warm start-ups indicates how many times the repeated operation of stopping when the rotation speed is reached can be performed within a safe electrical and mechanical range. To "1
H "and" 2 times "are described as" 2H ".

The temperature curve of the stator winding of the motor in the case of "3C2H" is as shown in FIG. 2, and T1r becomes a very hot state and restarts when operation is continued from a state where restart is impossible. Cooling time required until it becomes possible ("2
(C1H), a cooling time required for a hot state when the operation is continued from the non-restartable state to a restartable state), and a T1s for a very hot state when the operation is stopped from the non-restartable state. (2C1H), the cooling time required for a restart from a non-restartable state to a hot state and a restartable state. (2C1H) Cooling time required for restarting from a state in which restarting is not possible to a hot state in the case where operation is continued from the state where restarting is not possible in the case of "2C1H" T1r = T2r), and T2s is a cooling time (“2C1H”) required to change from a very hot state to a hot state when stopped. Is the cooling time required to reach the hot state when stopped from the non-restartable state, T1s = T2s), and Tc is the cooling time required to reach the cold state when stopped from the hot state. Time.

The state transition flow of the stator winding temperature of the motor is as shown in FIG. 3, that is, in "3C2H", the state where the temperature of the stator winding of the motor is equal to the ambient temperature (cold). Start from, and stop when the rated rotation speed is reached, it will be in a hot state, restart immediately and stop when the rated rotation speed is reached, it will be in a very hot state, restart immediately from the belly hot state and immediately restart when the rated rotation speed is reached. When stopped, restart is disabled. When the operation is continued from the state in which restart is not possible, the state becomes very hot after a lapse of time T1r, and restart is possible. When the state is stopped from the state in which restart is not possible, T1s (>)
After a lapse of time T1r), the state becomes a belly hot state, and the apparatus can be restarted. If the operation is continued from the very hot state, the state becomes hot after a lapse of T2r, and if the operation is stopped from the very hot state, the state becomes T.
After a lapse of time of 2s (> T2r), a hot state is set. When the operation is continued from the hot state, the temperature is maintained at the stable temperature in the hot state, and when the operation is stopped from the hot state, the state changes to the cold state after a lapse of time Tc. On the other hand, in “2C1H”, the motor is started from a state in which the temperature of the stator winding of the motor is equal to the ambient temperature (cold). If it is stopped upon arrival, it will be in a state in which it cannot be restarted. When the operation is continued from the non-restartable state, a hot state is established after a lapse of time T1r, and restart is possible. When the operation is stopped from the non-restartable state, a time T1s (> T1r) elapses. It will be hot and restartable. When the operation is continued from the hot state, similarly to the case of "3C2H", the temperature is maintained at the stable temperature while being in the hot state, and when the operation is stopped from the hot state, the state becomes the cold state after a lapse of Tc. .

FIG. 4 is a circuit diagram for monitoring the number of startups of the "3C2H" motor according to an embodiment of the present invention. The state where the temperature of the stator winding of the motor is equal to the ambient temperature is set as an initial state. Detecting whether the motor is started or stopped, and based on the elapsed time in the continuous operation state or the elapsed time in the stopped state, the temperature of the stator winding of the motor is changed from the ambient temperature to the limit temperature. (Cold, hot, berry hot (“2C1
"H" is the same as "Hot") or cannot be restarted)
Is recognized, and if it becomes impossible to restart,
An alarm is issued, and the waiting time until restart is enabled is displayed as a countdown display.

In FIG. 4, reference numeral 1 denotes a start signal which becomes "1" when the motor is started, and "0" when it is stopped, and 2 denotes a long time after the motor is stopped. A cold signal indicating that the temperature of the stator winding is at the ambient temperature, 3 is a hot signal indicating that the temperature of the stator winding of the motor is at a stable temperature when the rated operation is continued, and 4 is a start signal. A belly-hot signal indicating that the motor that has reached the limit can be restarted once after the required cooling time has elapsed. 5 is a non-restartable signal that indicates that the motor has restarted once from the belly-hot state. Where the cold signal 2 is output from the single flip-flop 6, the hot signal 3 is output from the single flip-flop 7,
The very hot signal 4 is output from a single flip-flop 8, and the restart disable signal 5 is output from a single flip-flop 9.

The cold signal 2 output from the single flip-flop 6, the hot signal 3 output from the single flip-flop 7, the very hot signal 4 output from the single flip-flop 8, and the output from the single flip-flop 9. Restart disable signal 5
The OR signal 11 output from the OR circuit 10 is input to the NOT circuit 12 and the on-delay timer 1
3, the OR signal 14 and the OR signal 15 output from the OR circuit 14 are input as a set signal to the single flip-flop 6, so that the cold signal 2, the hot signal 3, the very hot signal 4, In an initial state in which none of the restart disable signals 5 is output, the single flip-flop 6 is set and the cold signal 2 is output.

The cold signal 2 and the pulse signal 17 output from the pulse generator 16 when the activation signal 1 changes from “0” to “1” are input to an AND circuit 18 and
The logical product signal 19 output from the D circuit 18 is
0, and the OR signal 21 output from the OR circuit 20 is input to the single flip-flop 7 as a set signal. 3 is output as "1" so that it is recognized that the motor is in a hot state.

The hot signal 3 and the pulse signal 17 output from the pulse generator 16 when the activation signal 1 changes from "0" to "1" are input to an AND circuit 22, and
The AND signal 23 output from the circuit 22 is converted to an OR circuit 24
And the OR signal 2 output from the OR circuit 24
5 is input to the single flip-flop 8 as a set signal, when starting from a hot state, the single flip-flop 8 outputs the belly hot signal 4 as “1” and the motor is in a very hot state. It is recognized as having become.

The belly hot signal 4 is input to the AND circuit 27 via the on-delay timer 26, and when the start signal 1 changes from "0" to "1", the pulse generator 1
6 is input to an AND circuit 27, and an AND signal 28 output from the AND circuit 27 is input to the AND circuit 27.
Is input as a set signal to the single flip-flop 9, when the startup is performed from the very hot state, the single flip-flop 9 outputs the restart impossible signal 5 as “1” and the motor cannot be restarted. Is recognized as having become.

The logical sum signal 21 output from the OR circuit 20 to the single flip-flop 7 as a set signal is input to the single flip-flop 6 as a reset signal, so that the motor changes from a cold state to a hot state. In such a case, the cold signal 2 output from the single flip-flop 6 is reset.

The single flip-flop 7 has a logical sum signal 15 output from the OR circuit 14 to the single flip-flop 6 as a set signal, and a logical sum signal 25 output from the OR circuit 24 to the single flip-flop 8 as a set signal. Is input as a reset signal via the OR circuit 29, so that when the motor changes from the hot state to the cold or very hot state, the hot signal 3 output from the single flip-flop 7 is reset. It is like that.

The single flip-flop 8 has a logical sum signal 21 output from the OR circuit 20 to the single flip-flop 7 as a set signal, and a logical product signal 28 output from the AND circuit 27 to the single flip-flop 9 as a set signal. Is input as a reset signal via the OR circuit 30, and when the motor changes from a very hot state to a hot or non-restartable state, the very hot signal 4 output from the single flip-flop 8 is output. It is reset.

A single OR flip-flop 9 is supplied with a logical sum signal 25 output as a set signal from the OR circuit 24 to the single flip-flop 8 as a reset signal. When the state is changed, the restart disable signal 5 output from the single flip-flop 9 is reset.

The restart impossible signal 5 which becomes "1" when the motor is in the restart impossible state and the start signal 1
The AND signal 32 output from the AND circuit 31 is input to the switching relay 33 as a switching signal. When the AND signal 32 is "1", the switching relay 33 is turned on. In FIG. 4, the signal is switched to the a side, and a preset cooling time T1r in the signal generator 34 is inputted from the switching relay 33 to the subtractor 35, and the counter 36 for counting the restart impossible signal 5 to the elapsed time. As a count start signal, and the elapsed time 37 counted by the counter 36 is input to a subtractor 35,
In the subtractor 35, the elapsed time 3 from the cooling time T1r
7 and the remaining time 38 is used as the restart disable signal 5
Is "1", the signal is output via the switching relay 39 which is switched to the "a" side in FIG. 4, and when the operation is continued from the state where the restart is not possible, the waiting time 4 until the restart becomes possible.
The countdown display is set to 0. still,
As shown in FIG. 5, when there are a plurality of motors to be monitored, the names of the motors are displayed to identify the corresponding motors, and the waiting time 40 until restart is enabled is displayed as a countdown display. An alert is also issued to urge you.

The AND signal 32 output from the AND circuit 31 is input not only as a switching signal of the switching relay 33 but also to a counter 41 as a count start signal, and the counter 41 outputs an elapsed time 42 (restart impossible). The time t) in the operation continuation state from the state is counted, and the cooling time T1 set in the signal generator 43 in advance is set.
s is divided by a preset cooling time T1r in the signal generator 44 to output a signal 45 of T1s / T1r.
And a multiplier 48 that multiplies the T1s / T1r signal 45 output from the divider 46 by the elapsed time 42 counted by the counter 41 and outputs a T1s · t / T1r signal 47
And a cooling time T1s preset in the signal generator 43 and a signal 4 of T1s · t / T1r output from the multiplier 48.
7 and a signal 49 of T1s−T1s · t / T1r is obtained.
And a T1s−T1s · t / T1r signal 49 output from the subtractor 50.
T1s-T1s.
t / T1r + t = T1s− (T1s−T1r) · t / T
Adder 52 that outputs 1r signal 51 to switching relay 33
Are provided.

The reason for this is that the operation is continued from the state where the restart is impossible, the case where the operation is stopped from the state where the restart is impossible, and the state where the restart is possible from the state where the restart is impossible during the cooling by the operation continuation. This is because the waiting time 40 until the motor can be restarted differs depending on whether the motor is stopped before the motor is stopped. That is, when the operation is stopped from the state in which restart is impossible, the activation signal 1 becomes “0”, the AND signal 32 output from the AND circuit 31 is “0”, and the switching relay 33
4, the elapsed time 42 counted by the counter 41 remains "0" while the cooling time T1s preset in the signal generator 43 is directly changed to the subtracter 50. Is input to the subtractor 35 via the adder 52 and the switching relay 33. In the subtractor 35, the elapsed time 37 is subtracted from the cooling time T1s. In FIG. 4, the signal is output through the switching relay 39 which is switched to the side a, and is counted down as a waiting time 40 until the vehicle can be restarted when the vehicle is stopped from the state where restart is impossible. It is like that. Further, if the motor is stopped before the restart becomes possible during the cooling due to the continuation of the operation from the state in which the restart is impossible, the start signal 1 becomes “0” at the time when the operation is stopped, and the switching relay 33 is turned off. , FIG.
Medium, the side is switched to the side other than a, and T1s- (T1s-T
1r) · t / T1r signal 51 is input from adder 52 to subtractor 35 via switching relay 33, and subtracter 35
, The elapsed time 37 is subtracted from T1s− (T1s−T1r) · t / T1r, which is the remaining cooling time obtained by interpolating T1s and T1r, and the remaining time 38 is the case where the restart disable signal 5 is “1”. In FIG. 4, the signal is output through the switching relay 39 which is switched to the a side, and can be restarted when the motor is stopped before the restart becomes possible during the cooling due to the continuous operation from the state where the restart is not possible. The countdown is displayed as the waiting time 40 until the time is reached.

The waiting time 40 before the system can be restarted is
When the waiting time 40 becomes smaller than "0", the signal is also inputted to a signal monitor switch 54 which outputs a cooling completion signal 53 from restart impossible.

The cooling completion signal 53 from the non-restartable state is
The signal is input to the R circuit 24, and when the cooling completion signal 53 from the non-restartable state changes from "0" to "1", a single flip-flop is output by the OR signal 25 output from the OR circuit 24. The reset 9 is reset so that the restart disable signal 5 is not output, and the single flip-flop 8 is set to output the very hot signal 4.

When the restart disable signal 5 is no longer output,
The switching relay 39 is switched to a side other than a in FIG. 4, a signal of “0” preset in the signal generator 55 is output from the switching relay 39, and the counter 36 and the counter 41 are output by the very hot signal 4. And are reset respectively.

The belly hot signal 4 which becomes "1" when the motor enters the belly hot state, and the start signal 1 are:
The AND signal 56 is input to the AND circuit 56, and the AND signal 57 output from the AND circuit 56 is input to the switching relay 58 as a switching signal. When the AND signal 57 as the switching signal is "1", the switching relay 58 is turned ON. In FIG. 4, the signal is switched to the a side, and a preset cooling time T2r in the signal generator 59 is input from the switching relay 58 to the subtractor 60, and the counter 61 for counting the elapsed time of the belly hot signal 4 is used.
Input to the counter 61 as a count start signal.
Is input to the subtractor 60, the subtractor 60 subtracts the elapsed time 62 from the cooling time T2r, and the remaining time 63 is converted to a value when the very hot signal 4 is "1". 4, the signal is output via the switching relay 64 switched to the a side, and when the operation is continued from the very hot state, the waiting time 65 until the hot state is reached is set to a value from "0". Cooling signal 66 from belly hot when it becomes small
Is input to a signal monitor switch 67 that outputs

The logical product signal 57 output from the AND circuit 56 is input not only as a switching signal of the switching relay 58 but also as a count start signal to a counter 68, and the elapsed time 69 (very hot state) , The time t ′) in the continuous operation state is counted, and the cooling time T2s preset in the signal generator 70 is changed to the cooling time T2 preset in the signal generator 71.
divider 7 that outputs a signal 72 of T2s / T2r divided by r
3, a multiplier 75 that multiplies the T2s / T2r signal 72 output from the divider 73 by an elapsed time 69 counted by the counter 68 and outputs a T2s · t ′ / T2r signal 74, and a signal generator 70. Cooling time T2 set in advance
s and a T2s · t ′ / T2r signal 74 output from the multiplier 75, and a subtractor 77 that obtains a T2s−T2s · t ′ / T2r signal 76 and outputs the T2s−T2s · t ′ / T2r signal 76. The elapsed time 69 counted by the counter 68 is added to the signal 76 of T2s−T2s · t ′ / T2r.
−T2s · t ′ / T2r + t ′ = T2s− (T2s−T
2r). An adder 79 for outputting a signal 78 of t '/ T2r to the switching relay 58 is provided.

The reason for this is that when the motor is continuously operated from the belly hot state, when the motor is stopped from the belly hot state, or when the motor is turned off before the motor becomes hot during cooling from the belly hot state by continuing the operation. This is because the waiting time 65 until the hot state is obtained differs between the cases where the operation is stopped. That is, when the operation is stopped from the very hot state, the activation signal 1 becomes “0” and the AND circuit 5
The logical product signal 57 output from 6 is “0”, the switching relay 58 is switched to a side other than “a” in FIG. 4, and the elapsed time 69 counted by the counter 68 remains “0”. The cooling time T2s preset in the signal generator 70 is used as it is in the subtractor 77 and the adder 79.
Is input to the subtractor 60 via the switching relay 58, and the subtractor 60 outputs the elapsed time 62 from the cooling time T2s.
Is subtracted, and the remaining time 63 is output via the switching relay 64 switched to the a side in FIG. 4 when the belly hot signal 4 is “1”, and the state is stopped from the belly hot state. The signal is output to the signal monitor switch 67 as a waiting time 65 until a hot state is reached. If the motor is stopped from the very hot state to the hot state during the cooling by continuation of operation, the start signal 1 becomes “0” at the time when the operation is stopped, and the switching relay 58 In FIG. 4, the side is switched to a side other than a, and T2s− (T2s−T2r) · t ′ /
The signal 78 of T2r is input from the adder 79 to the subtractor 60 via the switching relay 58, and the subtractor 60
T2s-, which is the remaining cooling time obtained by interpolating 2s and T2r
The elapsed time 62 is subtracted from (T2s−T2r) · t ′ / T2r, and the remaining time 63 is the very hot signal 4
Is "1", the signal is output via the switching relay 64 which is switched to the a side in FIG. 4, and the motor is stopped from the very hot state to the hot state during the cooling by the continuous operation. In such a case, the signal is output to the signal monitor switch 67 as a waiting time 65 until a hot state occurs.

The cooling completion signal 66 from the belly hot output from the signal monitor switch 67 is output from the OR circuit 2
0, and when the cooling completion signal 66 from the berry hot changes from “0” to “1”,
The single flip-flop 8 is reset by the logical sum signal 21 output from the OR circuit 20 so that the very hot signal 4 is not output, and the single flip-flop 7 is set to output the hot signal 3.

When the belly hot signal 4 is no longer output, the switching relay 64 is switched to a side other than a in FIG. 4, and a signal of "0" preset in the signal generator 80 is output from the switching relay 64. At the same time, the counter 61 and the counter 68 are reset by the hot signal 3 respectively.

The hot signal 3 which becomes "1" when the motor is in a hot state and the negation signal 82 of the start signal 1 outputted through the NOT circuit 81 are obtained by the AND circuit 8
3 and outputs an AND signal 84 output from the AND circuit 83 to an on-delay timer 85 in which a time delay corresponding to a cooling time Tc required to become cold when stopped from a hot state is set. The delay signal 86 output from the on-delay timer 85 is "0"
Is changed from "1" to "1", the OR signal 15 output from the OR circuit 14 causes the single flip-flop 7
Are reset so that the hot signal 3 is no longer output, and the single flip-flop 6 is set to output the cold signal 2.

In one example of the embodiment of the present invention shown in FIGS. 1 to 5, the state in which the temperature of the stator winding of the motor is equal to the ambient temperature is set as an initial state, and the motor is started or stopped. Is detected, and the temperature of the stator winding of the motor is set stepwise from the ambient temperature to the limit temperature based on the elapsed time in the continuous operation state or the elapsed time in the stopped state. It is recognized which of the temperatures is equal to the set temperature (cold, hot, belly hot, or non-restartable), and if it becomes impossible to restart, an alarm is issued, The wait time until restart becomes possible is displayed as a countdown.

As a result, when the motor cannot be started, there is no need for the operator to actually measure and confirm the temperature of the stator winding or to measure the cooling time resulting from the specification of the motor. In addition, there is no possibility that the measurement results will be varied by the operator, and the burden on the operator will be reduced.

In this way, when the motor cannot be started, it can be reliably detected and the waiting time until the motor can be restarted can be accurately grasped, and the burden on the operator can be reduced. obtain.

FIG. 6 is a circuit diagram for monitoring the number of startups of the "2C1H" motor according to an embodiment of the present invention. In FIG. 6, the same reference numerals as those in FIG. 4 denote the same parts. This indicates that the motor is in a hot state where the stator winding temperature is stable at the time of continuation of rated operation, and after the required cooling time has elapsed for the motor that has reached the start limit, it is restarted once more The basic configuration is exactly the same as the example shown in FIG. 4 except that the berry hot state that can be performed is the same state.

Also in the example shown in FIG. 6, a state where the temperature of the stator winding of the motor is equal to the ambient temperature is set as an initial state.
Whether the motor is started or stopped is detected, and the temperature of the stator winding of the motor is determined based on the elapsed time in the continuous operation state or the elapsed time in the stopped state,
Equivalent to any of the set temperatures set in stages from the ambient temperature to the limit temperature (cold,
Hot or non-restartable)
If the motor cannot be restarted, an alarm is issued and the waiting time until the motor can be restarted is counted down. In addition, there is no need to measure and confirm the temperature of the stator windings or measure the cooling time resulting from the specifications of the motor, so that there is no risk that the measurement results will be varied by the operator, and the burden on the operator will be reduced.

Thus, in the case of the example shown in FIG.
As in the case of the example shown in FIG. 5, when it becomes impossible to start the motor, it can be reliably detected, and the waiting time until the motor can be restarted can be accurately grasped. The burden on the operator can be reduced.

It should be noted that the monitoring apparatus for limiting the number of times the motor is started according to the present invention is not limited to the above-described example.
It is needless to say that various changes can be made without departing from the gist of the present invention, such as not only the motor of "3C2H" or "2C1H" but also a motor of any specification.

[0046]

As described above, according to the apparatus for monitoring the number of times of starting of the motor according to the present invention, when the motor cannot be started, it can be reliably detected and restarted. It is possible to obtain an excellent effect that the waiting time until the actual time can be accurately grasped and the burden on the operator can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a definition and description of a temperature state of a stator winding of a motor in an example of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a temperature curve of a stator winding of a motor according to an example of an embodiment of the present invention.

FIG. 3 is a diagram illustrating a state transition flow of a temperature of a stator winding of a motor in an example of an embodiment of the present invention.

FIG. 4 is a circuit diagram (for “3C2H”) for monitoring the number of startups of a motor according to an example of an embodiment of the present invention;

FIG. 5 is a diagram illustrating a display example when a restart is disabled in an example of an embodiment of the present invention.

FIG. 6 is a circuit diagram (for “2C1H”) for monitoring the number of startups of a motor according to an example of an embodiment of the present invention;

[Explanation of symbols]

 1 Start signal 2 Cold signal 3 Hot signal 4 Very hot signal 5 Non-restart signal 40 Waiting time 53 Cooling complete signal from non-restartable 66 Cooling complete signal from very hot T1r Cooling time T1s Cooling time T2r Cooling time T2s Cooling time Tc cooling time

Claims (1)

[Claims] The motor is started from a state where the temperature of a stator winding of the motor is equal to the ambient temperature, and stopped when a rated rotation speed is reached.
Restarts immediately and starts from the state where the number of cold start times, which indicates the number of repetitive operations of stopping when reaching the rated rotation speed, and the temperature of the stator winding of the motor equal to the stable temperature during continuous rated motor operation A motor start frequency limit monitoring device that determines the number of times of the hot start limit that indicates how many repetitive operations of stopping when the rated speed is reached, restarting immediately and stopping when the rated speed is reached can be performed. With the state where the temperature of the stator winding of the motor is equal to the ambient temperature as an initial state, it is detected whether the motor is started or stopped, and the elapsed time in the continuous operation state or the elapsed time in the stopped state. The temperature of the stator winding of the motor is equal to which of the set temperatures set in steps from ambient temperature to the limit temperature. Knows, if it becomes impossible to restart,
A motor start count limit monitoring device, which is configured to issue an alarm and display a countdown display of a waiting time until a restart is possible.