SYS-2. Design for short and wide speed ranges

The chief engineer is to design drive system for the three similar conveyors with different operational speed ranges. Available information (common for the three conveyors):

• One drum to be driven
• Gearbox: helical 1-stage, ratio 1:5
• No overloads, duty cycle – 100%
• Air-conditioned clean power house, abundant heat removal capability
• Distance between the driven drum of the conveyor and the FC (cable length) – 30 m
• Grid 400 V
• Rated torque 5 kNm
• Cooling: cooling water is not available. Consider the two air-cooling variants: (a) IC411, (b) IC416

Difference between the conveyors: speeds (min-max)

• 1 case: 40 - 200 rpm (wide speed range)
• 2 case: 180 - 200 rpm (narrow speed range)
• 3 case: 180 - 206 rpm (overspeed)

Help the chief engineer to design the three systems. Record weight and cost of motor and of frequency converter for each case. Draw conclusions and explain. Can you explain the results/conclusions as electric machine designer? Converter designer? System designer?