The Positorq brake can be used for three major types of applications:
How to Select a Positorq Tension Brake
The selection of a Positorq for a tension control application will vary depending on the type of tension application. The most common types of applications are:
For a Constant Unwind application the two Torque Requirements to be considered are:
When Unwinding in Sets, there are three Torque Requirements to be considered.
The Total Torque Required when stopping at the first set stop is: (1)the total of the torque to maintain tension plus (2) the torque to stop the roll.
The larger of (1) The Total Torque required at set stop or (2) The Torque required for a Panic
Stop, should be used for selection purposes.
The same basic tension brake parameters are used for the winch brakes. There are some differences such as the drum diameter remains constant.
The following formulas are used to find the required torque capacity. Calculating the torque of a full roll and that at set stop is the same except for the difference in WK 2. and RPM.
(1) Tension Torque - Torque to maintain constant tension.
(2) Stopping Torque - Torque required to stop roll.
Ts = Torque (Lb. Ft.) for panic or set stop
(3) Total Torque - Total Torque required for set stop.
TT = Torque (Lb. Ft.) at set stop
(1) Thermal Horsepower to maintain tension - Torque to maintain constant tension.
THPt = Thermal Horsepower (tension)
Thermal Horsepower relates to the amount of energy that must be absorbed, and is used to size the cooling system. Usually the thermal horsepower absorbed to maintain tension is satisfactory for calculating Cooling System Capacity, however in some cases where a very small PLI is required the thermal energy to stop the roll may be the limiting factor. The following formula can be used to determine the Thermal Horsepower.
The Ideal Brake for High Torque - Low Speed Applications
In a Dynamometer Application normally a Positorq Brake is used to resist rotation of a shaft at some torque load. It can be used to absorb energy continuously as in product life testing, or for a short time for maximum load carrying capability. It can also be used to lock-up the shaft for destructive testing.
The Positorq Brake size is based primarily on torque and thermal horsepower. Sizing of the Positorq Brake should be done by application engineers at Force Control, however the following information will be required for sizing and determining cooling systems.
Maximum Torque - Maximum torque at any speed.
|HP = Maximum continuous horsepower through each brake
Torque = Maximum Continuous Torque (Lb. Ft.) at each brake
RPM = Speed at brake
THP = Thermal Horsepower to be dissipated through each brake
There are many unique and specific requirements for load brakes such as response, cycle rates, minimum torque, mounting of the brakes, location of the cooling reservoir, and actuation type to name a few. A full review with one of our applications engineers should be completed before making decisions.