What is the belt tension force?

Since several forces act on a belt drive, the most important forces on belt drives are named below in order to understand the significance of

the belt tension force. The belt connects a drive pulley with a driven pulley. The drive pulley is driven by a motor which generates a torque and

transmits it to the drive pulley. The belt transmits this torque in the form of a circumferential force to the driven pulley. The following forces are

important.

The circumferential force: The circumferential force corresponds to the effective force to be transmitted by the belt. The circumferential force

depends on the applied engine power and thus on the torque as well as on the engine speed and the pulley diameter. In order to maintain the

balance of forces, the circumferential force causes the formation of different forces in the strands of the belt. The difference between the forces

between the loaded and unloaded runs corresponds to the circumferential force transmitted to the belt.

The frictional force: The frictional force at the drive pulley ensures that the torque of the motor is transmitted via the belt to the driven pulley.

At the driven pulley, a usable torque is generated which corresponds to the product of the circumferential force and half the diameter of the

driven pulley.

The centrifugal force. The centrifugal force increases with increasing speeds and causes the belt to stretch and thus lose grip. In this case, the

centrifugal force acts against the adhesion force.

The pretensioning force: The pretensioning force / span force / belt tension is different under dynamic conditions on the loaded and the

unloaded span. In static conditions, the belt tension is identical in both runs. In the static state, the pretensioning force must be set in such a

way that under dynamic conditions there is sufficient adhesion to the pulleys to ensure the transmission of power from the belt to the pulley,

while at the same time taking into account the centrifugal forces acting on the belt in the operating state. However, the belt tension must not

be set too high, as otherwise belt damage and/or bearing damage may occur under load. The correct belt tension must be selected specifically

for each belt and the corresponding application. In most cases, belt manufacturers specify the corresponding belt tension in the form of forces

or frequencies. A belt tension meter can then be used to accurately determine the required belt tension after installation and before

commissioning a belt drive.

Why should you measure the belt tension force?

The measurement of the belt tension is always necessary when machines and systems are to be optimally maintained. A belt drive reaches its

maximum service life only if it is designed and adjusted for its use. This means that the belt should be tensioned for the specific application

optimally and the pulleys – precisely aligned.

Belt Tension Meter in application on a packaging machine.With the help of the belt tension

measuring device, the strand force can be determined exactly when the belt is under stationary conditions.

Long service life and high performance of the equipment and the machines – is the wish-goal of every user, either company or an individual. In

many industries, in particular, in various mechanisms, belts are an important and necessary part. The smallest deviations from the standards

may lead to serious consequences, like systems failure, that is why, it is especially important to regularly check the belt tension, since only when

this value is absolutely correct and optimal, the best performance may be provided. Not only weaker than necessary tension, but also the

tension that exceeds the standards, may cause serious and, which is important, preliminary, degradation of the belt and drop of the

performance. This could cause serious machine failures with unplaned downtime and high repairing costs. For example, wrong belt tension in

the generator of the car is devastating in both cases and may be dangerous and lead to the complete wear of the mechanisms. Significant

costs – is just one of the items in the list of the possible problems that may follow. Even if the belt is not broken, the change in its function

does not remain unimportant for the whole system or mechanism, and that is why it is actually one of the priority tasks to keep this issue under

control.

To do this is easy with the help of the belt tension meter, which represents a small, but a very useful device which can help the user to

determine the belt tension in the system to be controlled and thus, indicate whether the prompt measures should be taken to adjust the

tension to the setpoint value.

Testing the tension manually remained in the past long time ago, and the best way to determine the tension is to use the device and by means

of the calculations get an exact data about the belt tension. The vibrations coming from the belt are not only registered by the belt tension

meter, the data are processed after they have been received by the optical sensor, and based on the characteristics of the belt (weight, width,

length), the final result is calculated and displayed on the lighted screen (in N and Hz).

The spectrum of application is wide, starting from individual applications in household (various devices and household equipment) or office to

industrial fields where it can be used for different conveyors, lifting equipment, elevators, automotive industry or agricultural machines.