JPH04359624A - Motor overload preventive device for circulating grain drier - Google Patents

Abstract

PURPOSE:To prevent a motor from stopping immediately and to work form being interrupted even if the current value is judged temporarily to be above a set value by judging the current value of a motor by classes being set optionally, and stopping the operation of the motor when the integrated value reaches the set value. CONSTITUTION:A current transformer 35 detects the current value of a motor 33, and the detection signal is input into a CPU 39 through an amplifier 36, an A/D converter 37, and an input circuit 38 the CPU 39 does sums and comparative operation, and when the integrated value reaches the set value, the CPU 39 outputs a signal. The output signal is sent to an electromagnetic switch 41 through an output 40 so as to stop the operation of the motor 33. What is more, the CPU 39 is set to open the electromagnetic switch 41 when it becomes that (set value)-(set value X time (second))=0. Hereby, even if the detected current value is judged temporarily to be above the set value, it never stops the operation of the motor interrupts the drying work, so the efficient drying of grains becomes possible.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor overload prevention device for a circulating grain dryer that prevents burnout due to overload of the motor.

0002

[Prior Art] A circulating grain dryer consists of a storage section, a drying section, and a grain collection section.The grain collection section is connected to the storage section via a grain lifting machine to form a circulating grain process. It is driven by a grain-lifting machine motor, a discharge valve motor, an exhaust fan motor, etc. After the grains put into the storage part are dried in the drying part, they are intermittently supplied to the grain collection part by a discharge valve provided below the drying part, and are fed from the grain collection part by a grain lifting machine. It is circulated until a predetermined moisture content is reached.

0003

[Problems to be Solved by the Invention] In the conventional circulation type grain dryer as described above, the current value of each motor that drives the conveyor, grain lifting machine, discharge valve, and exhaust fan is controlled by a current transformer (CT).
The detection signal is input to the control device. When the control device determines that the detected current value is greater than or equal to the set current value, an output signal from the control device opens the electromagnetic switch interposed in the power supply of each motor, stopping the operation of each motor and preventing overload. This prevents burnout due to

However, when it is determined that the detected current value of the motor is higher than the set current value, the motor operation is immediately stopped and the drying operation is stopped. The value is often exceeded. If the grain is temporarily clogged, normal drying operations can be continued once the clog is cleared, but in conventional circulation dryers like the one mentioned above, drying operations are stopped even in this case. The drawback was that efficiency decreased.

The present invention solves the drawbacks of the conventional device as described above, and even if the current value detected by the current detector is temporarily determined to be higher than the set current value, the operation of the motor is immediately stopped and the drying process is started. It is an object of the present invention to provide a motor overload prevention device for a circulating grain dryer that does not interrupt work.

[0006]

[Means for Solving the Problems] In a circulating grain dryer in which a storage section, a drying section, a grain collection section, and a grain lifting machine are formed into a circulating grain process, the power source of each motor that drives each section of the dryer is The intervening current detector and the current value detected by the current detector at arbitrary time intervals are classified into arbitrarily set classes,
A motor overload prevention device for a circulating grain dryer comprising a control device that stops the operation of each motor when the cumulative value of coefficients set for each of the determined classes reaches an arbitrarily set value. be.

[0007]

[Operation] A detection signal from a current detector connected to the motor's power source is input to the control device, and the control device discriminates the detected current value into an arbitrarily set class. Then, when the cumulative value of the determined coefficients reaches the set value, the operation of the motor is stopped.

[0008]

Embodiments An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a motor overload prevention device, FIG. 2 is an enlarged view showing a drive section of a circulating grain dryer, and FIG. 3 is a partial front cross-sectional view of the circulating grain dryer.

Reference numeral 1 denotes a circulating grain dryer, in which a conditioning chamber 2 is provided in the upper part, a ventilation drying section 3 is provided in the lower part, and a grain lifting machine 4 is erected on one side to form a circulating grain drying process. do. The ventilation drying section 3 includes a drying chamber 5 and a hot air chamber 6 formed of a porous wall plate.
and a discharge chamber 7 are arranged in parallel, and the upper part of each drying chamber 5 is communicated with the tempering chamber 2. The lower part of the drying chamber 5 is connected to a grain flow path 8, and a discharge valve 9 is provided at the discharge port. Reference numeral 10 denotes a grain collection gutter, and a lower conveyor 11 is provided at the bottom of the gutter, and the lower conveyor 11 is connected to the tempering chamber 2 via a grain lifting machine 4, an upper conveyor 12, and a scattering plate 13.

A belt 16 with a large number of buckets 15 attached thereto is wound between upper and lower pulleys 17 in the conveyor case 14 of the grain lifting machine 4, and an opening 18 at the upper end of the grain lifting machine 4 is connected to a drain trough 1.
It is connected to the upper conveyor 12 via 9, and 20 is a motor for driving the grain lifting machine.

A guide plate 21 is installed at an angle between the belts 16 and 16 of the grain lifting machine 4 to collect the returned grain from the bucket 15, and the guide plate 21 is connected to a moisture measuring device 23 via a supply cylinder 22. The moisture measuring device 23 is connected to a lower opening (not shown) of the conveyor case 14 via a discharge gutter 24 and a return gutter 25.

Reference numeral 26 denotes a discharge valve drive device (see FIG. 2), which includes sprockets 27, 27 attached to the shafts of the discharge valves 9, 9, a sprocket 29 attached to the discharge valve drive motor 28, and a tension sprocket 30. Wind the chain 31. Further, a pulley 32 attached to the shaft of the lower conveyor 11 and a lower conveyor driving motor 33 are connected by a belt 34.

Next, the circuit of the motor overload prevention device is shown in FIG.
Explain with reference to. A current transformer (CT) 35 that detects the current value of the motor 33 is interposed in the power supply of the motor 33 (the same applies to the motor 20 and the motor 26).
5 communicates via an amplifier 36, an AD converter 37, and an input circuit 38 to a CPU 39 that calculates various input values. CPU
39 is connected to the motor 3 via an output circuit 40 and an electromagnetic switch 41.
Contact 3.

Next, the operation of the above configuration will be explained. Grain (for example, paddy) supplied to a hopper (not shown) is lifted by a grain lifting machine 4, passes through an upper conveyor 12, and is evenly scattered and deposited in a tempering chamber 2 from a scattering plate 13. be done. Next, when the heat generating device (not shown) and the exhaust fan (not shown) are activated and the discharge valve 9 is rotated, the grains in the tempering chamber 2 flow down into the drying chamber 5. Grain flowing down inside the drying chamber 5 is dried at high temperature by drying air flowing laterally from the hot air chamber 6 to the exhaust chamber 7, and the drying air is discharged from the exhaust chamber 7 to the outside of the machine by an exhaust fan (not shown). . The grains that have been hot-air-dried by the drying air flow down a grain flow path 8 and are intermittently discharged by a discharge valve 9. The discharged grain flows down the grain collection gutter 10, is sent to the grain frying machine 12 by the lower conveyor 11, and is again input into the tempering chamber 2, where it is circulated and dried until the moisture measuring device 21 detects a predetermined moisture content. Ru.

The grain lifted by the grain lifting machine 4 is transported into the bucket 15 due to vibrations during transportation and discharge into the downflow gutter 19.
It spills between the belts 16 and 16. The spilled grains are collected by the guide plate 21, flow down the supply cylinder 22 from the guide plate 21, and are supplied to the moisture measuring device 23, where the moisture content of the grains is measured. The grain whose moisture content has been measured is discharged from the moisture measuring device 23, flows down the discharge gutter 24, and returns to the return gutter 25.
and is supplied to the lower part of the conveyor case 14.

Next, the operation of the motor overload prevention device will be described (see FIG. 1). The current value of the motor 33 is detected by a current transformer 35, and the detection signal is amplified by an amplifier 36 and then
A converter 37 performs AD conversion. The AD-converted conversion value is input to the CPU 39 via the input circuit 38, and the CPU 3
Arithmetic and comparison operations are performed in 9. When the integrated value of the detected current value reaches the set value by the calculation, a signal is output from the CPU 39, and the output signal is sent to the electromagnetic switch 41 via the output circuit 40, thereby opening the electronic switch 41. Operation of motor 33 is stopped.

Next, control in the CPU 39 will be explained. The storage device of the CPU 39 is set so that when the set value - coefficient value x time (seconds) = 0, the electromagnetic switch 41 is opened and the operation of the motor 33 is stopped. Although the set value and coefficient value can be set arbitrarily, in this example,
The set value is 200, and the coefficient values are as shown in Table 1.

[0018]

[Table 1] For example, if the detection current is 120% and the cumulative time is 20 seconds,
If the cumulative time is 20 seconds at 140% and 8 seconds at 160%, then 200- 1 x 20- 5 x 20-1
0×8=0. In other words, 48 seconds after detecting the abnormal current value, the motor 3
3 is stopped.

Furthermore, even if an abnormal current value is detected, if the current value returns to the rated current value before reaching the set value, if the current value remains unchanged, the motor 33 will stop in a short time when the next abnormal current value is detected. Resulting in. In other words, if the set value is 200, the state where the detected current is 200% of the rated current is
If the current returns to normal after 4 seconds, the current value is 4.
0 (200-40×4=40), 120%
However, the operation of the motor 33 stops after 40 seconds (40-1×40=0).

[0020] Therefore, the CPU 3 is configured to add an arbitrary number to the current value, for example, 2 every second to return to the set value.
9 storage device. Then, in the above example, the set value (
200) and enters a normal detection state.

[0021]

[Effects of the Invention] According to the motor burnout prevention device for a circulating grain dryer according to the present invention, even if the current value detected by the current detector is temporarily determined to be higher than the set current value, the operation of the motor is immediately stopped. Since there is no need to interrupt the drying process, it is possible to dry grains efficiently.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a motor overload prevention device.

FIG. 2 is an enlarged view showing the drive section of the circulating grain dryer.

FIG. 3 is a partial front cross-sectional view of the circulating grain dryer.

[Explanation of symbols]

1 Circulating grain dryer 2 Tempering chamber 3 Ventilation drying section 4 Grain lifting machine 5 Drying room 6 Hot air room 7　Exhaust room 8 Grain flow path 9 Discharge valve 10 Grain collecting trough 11 Lower conveyor 12 Upper conveyor 13　Scatter disk 14 Conveyor case 15 Bucket 16 Belt 17 Pulley 18 Opening 19 Downstream gutter 20　Grain lifting machine drive motor 21 Information board 22 Supply cylinder 23 Moisture measuring device 24 Discharge gutter 25 Return gutter 26 Discharge valve drive device 27 Sprocket 28　Discharge valve drive motor 29 Sprocket 30 Tension sprocket 31 Chain 32 Pulley 33 Lower conveyor drive motor 34 Belt 35 Current transformer 36 Amplifier 37 AD converter 38 Input circuit 39 CPU 40 Output circuit 41 Electromagnetic switch

Claims (1)

[Claims] Claim 1: In a circulating grain dryer in which a storage section, a drying section, a grain collection section, and a grain lifting machine are formed in a circulating grain process, current detection is provided in the power supply of each motor that drives each part of the dryer. When the current value detected by the current detector and the current detector at any given time is classified into an arbitrarily set class, and the cumulative value of the coefficient set for each class has reached the arbitrarily set value. and a control device for stopping the operation of each of the motors.