Page 40 - Electric Drives and Electromechanical Systems

32 Electric Drives and Electromechanical Systems

Table 1.2 Requirements to be considered during the selection of the components of
a motor-drive system.
Load requirements Maximum speed
Acceleration and deceleration
Motion profile
Dynamic response
External forces
System integration Mechanical fittings
Bearing and couplings
Cooling
Compatibility with existing systems
Electrical supply specifications and compatibility
Provision of cyber security measures if required
Life-cycle costs Initial costs
Operational costs
Maintenance costs
Disposal costs
Environmental factors Safety and risk management
Electromagnetic compatibility
Climatic and humidity ranges

specification of a component is changed, the effect on the complete system must
be considered.
Verification. Prior to procuring the components, a complete check must be made
to ensure that the system fits together in the space allocated by the other members
of the design team.
Testing. Theoretically, if all the above steps have been correctly followed, there
should be no problems. But this is not always the case in the real world, commis-
sioning modification may be required. If this is required care must be taken to
ensure that the performance of the system is not degraded.
One of the main design decisions that is required is the selection of the correct motor
technology. With the rapid development in this field, number of options are available;
each option will have benefits and disadvantages. In the consideration of the complete
system the motor determines the characteristic of the drive, and hence determines the
power converter and control requirements. A wide range of possibilities exist, however
only a limited number of combinations will have the broad characteristics which are
necessary for machine-tool and robotic applications, namely:
A high speed-to-torque ratio.
Four-quadrant capability.
The ability to produce torque at standstill.
A high power-to-weight ratio.
High system reliability.