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System Manual V2 – MOVITRAC® B
6
Description of applications
Project Planning
6.3
Description of applications
6.3.1
Project planning for trolleys
The motor load in the dynamic sections determines the peak motor power to be dimen-
sioned. The thermal load determines the required continuous motor power. Refer to the
travel cycle for determining the thermal load. The speed profile is the significant factor
in determining the self-cooling of the motor.
6.3.2
Project planning for hoists
In practice, you must take particular account of thermal and safety-relevant criteria when
sizing hoists.
The control must be designed so that the direction of rotation of the drive can only be
changed when it is at a standstill.
Caution!
Speed monitoring is set by changing parameters 500 / 502 and 501 / 503. The sagging
of hoists cannot be avoided safely when monitoring is deactivated or the delay time is
set too long.
Thermal
considerations
In contrast to trolleys, hoists require approx. 70 ... 90 % of the rated motor torque 90 %
of rated torque of the motor.
Starting torque
The highest operating torque is required for acceleration with maximum load in the
upwards
hoisting direction.
As a rule, design the 4-pole gearmotor for a maximum speed of
•
2100 rpm (70 Hz) at a transition speed of 1500 rpm (50 Hz)
•
2500 rpm (83 Hz) at a transition speed of 1800 rpm (60 Hz)
This means the gear unit input speed is increased by a factor of 1.4. This is why you
have to select a 1.4 times higher gear unit reduction ratio. The motor will not lose any
torque on the input shaft in the field weakening range (50 ... 70 Hz or 60 ... 83 Hz). The
higher gear unit ratio compensates for the inversely proportionate decrease in torque in
relation to speed. Furthermore, the startup torque is 1.4 times greater. Further
advantages are that the speed range is greater and the self-cooling of the motor more
powerful.
Hoist voltage/speed characteristic curve
Select the motor power for hoists according to the load type:
a = Recommended voltage/speed characteristic curve and resultant torque profile
B = Torque reserve range
Summary of Contents for MOVITRAC MC07B0037-2A3-4-00
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