Specify mechanical input and electrical output together
A permanent magnet generator inquiry needs both sides of the energy conversion boundary. On the mechanical side, define shaft speed range, continuous and transient torque, direction, overspeed, inertia and the prime mover. On the electrical side, define rated power, voltage, phase arrangement, frequency requirement, load type, rectification, converter and grid or storage interface. A power value without speed does not establish torque, and a voltage value without speed and winding context does not establish a generator design.
Describe the complete operating envelope rather than one rated point. Wind, hydro and engine-driven systems may spend substantial time away from nominal speed. The electrical interface may regulate voltage or DC-link conditions while mechanical input varies. These control responsibilities should be identified early so the generator, converter and supervisory control are designed as a coordinated system.
How a PMSG generates electrical power
A permanent magnet synchronous generator uses rotor magnets to establish magnetic flux. Rotation changes the flux linkage of the stator windings and induces an alternating voltage. Electrical frequency is related to mechanical speed and pole count. Terminal behavior then depends on winding design, load, internal impedance, temperature and the connected power electronics. The principle is simple, while the usable system envelope requires electromagnetic, thermal and mechanical design.
Permanent magnets remove the need for a separate rotor field winding and its excitation system, but magnet material and rotor construction introduce their own design constraints. Demagnetization margin, short-circuit behavior, overspeed retention and thermal conditions need review. Do not infer these limits from a generic PMG definition. They belong in the project-specific technical data and verification plan.
Torque and structural loads matter
Generator torque follows power divided by angular speed, so lower-speed machines can require substantial torque and larger structural interfaces. The shaft, rotor, bearings, housing, base and coupling must withstand steady torque, transient events and overspeed. In direct-drive wind or hydro arrangements, the generator may also interact with large external bearings or flexible structures.
Provide the mounting concept, shaft and coupling drawing, external radial and axial loads, allowable mass and envelope, vibration environment and balancing requirement. Identify which party supplies bearings and structural supports. A generator that meets electrical output requirements can still be unusable if the mechanical interface or rotor dynamics are not compatible with the prime mover.
PMG request-for-quotation package
Provide rated and maximum power, nominal and full speed range, continuous and transient torque, desired voltage and phase arrangement, frequency or DC-link requirement, converter details, load type, duty cycle, cooling, environment, overspeed, mounting, shaft and coupling information, allowable envelope and required sensors. Add the prime-mover curve where available.
Mark which values are fixed and which can be optimized. If the project is at concept stage, state the uncertainty range rather than inventing a precise point. ENNENG can then identify feasible directions and the calculations or tests needed next. This creates a technical record that can support design review, quotation and later acceptance planning.