SEW-Eurodrive MOVITRAC 07, Системное руководство

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5
86
System Manual – MOVITRAC® 07
Description of applications
Project Planning
5.3 Description of applications
Inverter selection
For MOVITRAC
®
07, there are two applications relevant for project planning.
100 % rated cur-
rent These are applications with constant load, for example:
• Conveyor drives
• Trolleys
• Hoists
125 % rated cur-
rent
These are applications with variable torque load, for example:
• Fans
• Pumps
Project planning
for trolleys
The motor load in the dynamic sections determines the peak motor power according to
which the dimensions are to be set. The thermal load determines the required continu-
ous power of the motor. Refer to the travel cycle for determining the thermal load. The
speed characteristic is a significant factor in determining the self-cooling of the motor.
Project planning
for hoists
In practice, the question of setting the size of hoists is addressed with regard to special
thermal and safety-critical criteria.
Thermal consider-
ations In contrast to trolleys, hoists require approx. 70 ... 90 % of the motor rated torque at con-
stant speed.
Starting torque
The motor requires the highest operating torque in the event of acceleration with maxi-
mum load and the upwards hoisting direction.
Always configure the 4-pole geared motor for a maximum speed of:
• 2100 rpm (70 Hz) with transition speed 1500 rpm (50 Hz)
• 2500 rpm (83 Hz) with transition speed 1800 rpm (60 Hz)
This means the gear unit input speed is increased by a factor of 1.4. Consequently, it is
also necessary to choose a gear ratio which is higher by a factor of 1.4. This measure
means the motor does not lose any torque at the input shaft in the field weakening range
(50 ... 70 Hz or 60 ... 83 Hz). The drive compensates for the inversely proportionate fall
in torque in relation to speed by means of the larger gear ratio. In addition, the motor
gets a run-up torque which is 1.4 times greater. Other advantages are that the speed
range is greater and the self-cooling of the motor more powerful.