Hoist-like applications
In many applications, the weight must be overcome continuously to move a mass. In such an application, if the weight generates the significant part of the load torque on the motor shaft, it is a "hoist-like application". This applies regardless of the direction of movement.
When dimensioning brakes, this application characteristic is of great importance for the following aspects:
- Selection of the braking torque
- Compliance with a minimum braking torque to ensure reliable holding and braking performance; see --- FEHLENDER LINK ---.
- Type of shutdown
- Use of fast shutdown to limit the speed increase occurring during the response time and to achieve reproducible stopping distances, see --- FEHLENDER LINK --- and --- FEHLENDER LINK ---.
- Limitation of permitted emergency-stop speed
- Avoidance of critical speeds that may impair friction coefficient stability during braking.
- Limitation of the permitted load ranges/overload range
- Avoidance of high thermal loading of the friction system in order to maintain friction coefficient stability, see --- FEHLENDER LINK ---.
The design procedures in this document assume that "hoist-like applications" are to be evaluated using rules for the "vertical" direction of movement. In addition to the design procedures, the following notes must be observed:
- For vertical applications with a counterweight, it may be necessary – depending on the load situation – to calculate the upward travel after the downward travel has been completed, and vice versa.
- Slewing gear drives with a non-vertical main axis (horizontal or inclined axes) and eccentric load distributions (e.g. vertical rotary tables) must be evaluated as hoist-like applications.
- Applications that are subject to external loads (e.g. wind loads, pressing forces) must also be designed as hoist-like applications.
- For special applications, such as winders, calenders, or applications with crank mechanisms, the design process is not directly applicable, as additional boundary conditions must be taken into account. These must be assessed for the respective application and included in a separate calculation.
- For winding drives, the exact boundary conditions for emergency-stop braking as well as the influencing factors to be considered must be evaluated, for example whether tensile forces in the wound material occurring during emergency-stop braking are to be taken into account. Where required, multiple separate calculations are necessary.
