The thermal overload mechanism can be reset manually after a cooling off period. Before
resetting, the root cause for actuating the thermal overload mechanism needs to be determined
and corrected.
To minimize the possibility of overheating the brake to a point where the thermal overload
mechanism will be actuated, the performance of the brake has to be matched to the requirements
of the application.
When selecting the brake model, consideration has to be given to brake torque, thermal
capacity, electrical power supply, housing material and any unusual conditions.
BRAKE TORQUE
As a general rule, brake torque is matched to the full load motor torque (brake and motor shaft
at the same speed). Depending on the type of application, the torque sometimes is increased by
a safety factor of 1.5 to 2. If factors such as stopping time, travel distance during stopping and
others, are important, the exact torque requirement has to be calculated, using the methods
contained in Dings selection guide.
THERMAL CAPACITY
Thermal capacity describes the capacity of the brake to perform the maximum number of
stops without excessive heat buildup that will actuate the thermal overload mechanism or
damage internal brake parts. The maximum number of stops depends on the rating of the brake,
load to be stopped and speed from which stops are made. To calculate the thermal capacity
requirements of the application, use the methods contained in Dings selection guide.
ELECTRICAL POWER SUPPLY
The coil of the electromagnet, which supplies the releasing force under normal operating
conditions, will operate properly with a tolerance of plus or minus 10% of rated voltage. A volt-
age higher than 110% will shorten the life of the coil considerably due to the higher temper-
ature generated inside the coil. A voltage of less than 90% may prevent the armature from mov-
ing towards the magnet frame. If this occurs, the coil will burn out within months.
UNUSUAL CONDITIONS
Please consult Dings Home Office, if ambient temperature is above 40oC (104oF), brake shaft
speed is over 3600 RPM, or any other unusual conditions exist.
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