This how to will explain how to calculate and choose a motor with sufficient power for a conveyor belt
Calculate the Power
To calculate the power of the motor for feeding the conveyor belt, we first need to know some variables, namely:
- The speed at which the object will move on the conveyor belt
- The weight of the object that will move on the conveyor belt
First, we need to determine how fast we want the object to move on the conveyor belt this is done by dividing the length of the conveyor belt by the number of seconds you want it to take until the object will reach from the beginning to the end.
Example:
If you have a 5-metre conveyor and you want the object to reach the end of the conveyor in 15 seconds you have to divide 5 by 15 which gives the result 0.33 metres/second.
After you know both variables, we can calculate the power by entering the following formula:
Power = Force / Velocity
Where Force is Frictional force = ยต * N (friction force * normal force of the object) = ยต * m * g
Where m is the mass of the object in kg and g is the gravitational constant 9,81 m/s2
The frictional forces differ in every situation here is a average range between frictional forces for following situations:
- For standard rubber conveyor belts on metal rollers or surfaces: ๐ โ 0.02 - 0.05
- For high-friction surfaces, like textured or coated belts: ๐ โ 0.1 - 0.3
- For low-friction applications, such as plastic belts or specialized coatings: ๐ โ 0.01 - 0.02
After you have determined both variables, we can determine the power of the motor in Nm/second by dividing the Force by the Velocity, where 1 Nm/second equals 1 Watt. To this you can add a safety factor of 10 to 20%.
Calculate the RPM
To determine the RPM of the motor, you need to know the following variables:
-
The diameter of the roller of the conveyor belt
-
The speed at which the object will move on the conveyor belt
First, we need to know the circumference of the roller this can be done by multiplying the diameter by ฯ (pi)
Example:
If I have a roller of 45mm then the circumference is 45 * ฯ = 141.3mm = 0.141m
So each time the roller rotates, the conveyor will be moved 0.141m. How many rotations must the roller make before the conveyor belt advances 1 metre? You can calculate this as follows:
0,141 meter ร 1 revolution
1 meter ร 1/0,141 meter = 141,5 RPM
By multiplying this by the speed of the object in metres/minute, you can calculate the RPM of the roller
Example
If you want an object to move at 20 metres/minute on a conveyor belt, the RPM of the roller with a diameter of 45mm will be as follows:
20 * 1/0.141 = 141.5 RPM
Calculate the Torque
To determine the Torque of the motor, we need to use the following formula:
Torque = Power (W) / Angular speed (Rad/Sec)
Where Angular speed can be calculated by converting the RPM of the roller to Rad/sec by multiplying the RPM by 2ฯ/60
Example:
If we have a RPM of 141,5 RPM we can determine the Angular speed by multiplying it by 2ฯ/60 which will give us 14,8 Rad/Sec
You can fill in the formula and determine the required Torque of the motor in Nm.
With these information we acquired from the calculations we can choose a motor accordingly.