01 |
Characteristic of Speed Control Motor |
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02 |
Selection of the motor |
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i = |
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Use the nearest approximated value of the gearhead (gear ratio=i) |
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03 |
Sample Calculation for Selection (Fig. 2) |
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Number of rotations = |
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Speed of belt conveyor |
Outer diameter of drum |
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= |
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≒ 3.18 [rpm] |
Number of rotations = |
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Speed of belt conveyor |
Outer diameter of drum |
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= |
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≒ 6.37 [rpm] |
Number of rotations = |
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Speed of belt conveyor |
Outer diameter of drum |
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= |
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≒ 12.74 [rpm] |
Number of rotations of the motor |
Number of rotations of the gearhead |
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= |
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≒ 102 |
With single direction rotation of the belt conveyor, change the speed of the item being transported to 1m/minute, 2m/minute, and 4m/minute.
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Drum diameter : 10㎝
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Operating torque : 30㎏ · ㎝
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Power : Single phase 110V 60㎐
Instantaneous braking in emergencies, but no holing power. ① MOTOR and CONTROLLER
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Rotation is in one direction and there is no holding power. Therefore, the induction motor is selected.
② Revolutions of output shaft of gearhead
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The number of rotations of the gearhead shaft when the belt conveyor speed is 1m/minute.
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Number of rotations of the gearhead shaft when the belt conveyor speed is 2m/minute.
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Number of rotations of the gearhead shaft when the belt conveyor speed is 4m/minute.
③ Gear ratio The gear ratio is calculated using the higher number of rotations of the gearhead. Using 102, since there is no such reduction ratio as 1/102, 1/100 is selected. ④ Number of rotations of motor shaft
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The number of rotations of the motor shaft is calculated by the number of rotations of the gearhead shaft x reduction ratio for each speed of the belt conveyor to get the following.
3.18 × 100 = 318 [rpm] 6.37 × 100 = 637 [rpm] 12.74 × 100 = 1274 [rpm] ⑤ Required torque of motor
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The transfer efficiency of a gearhead with gear ratio 100 is 66%, so the required torque of the motor is
Operating torque |
Gear ratio × Efficiency |
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= |
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≒ 0.45 [kg·cm] |
⑥ Selection of motor
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From the N-T curve of the induction motor, it can be seen that the K8IG25NC-S motor and the K8G100B gearhead can be combined to use. However, in such a case, make sure that the inertia load should fall within the specification of the selected motor.
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04 |
The Principle of Speed Control |
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