• Both utilize conductive cores (copper/aluminum) with insulating coatings, serving as electromagnetic coils for energy conversion in motors/transformers.
• Must meet fundamental requirements:
✓ Mechanical properties (abrasion resistance, flexibility)
✓ Electrical properties (insulation strength)
✓ Thermal properties (temperature class)
✓ Chemical resistance (anti-corrosion).
Polyester enameled wires (QZ-type) and modified polyester wires (QZ(G)-type), common in standard motors, are occasionally used in low-power variable frequency motors under non-high-frequency-pulse conditions.
Variable Frequency Motors:
• Corona-resistant wires: Require polyimide/polyamide-imide composite coatings (e.g., QZY/XY-type) or metal-oxide-doped wires (titanium/chromium) to withstand high-frequency pulse voltages (e.g., IGBT-PWM-induced spikes).
• Pulse voltage endurance: 200× higher than standard wires. Example: DuPont’s Reliawire™ significantly extends corona-resistant lifespan.
Standard Motors:
• Typically use polyvinyl acetal (QQ-type) or standard polyester (QZ-type) wires with limited corona resistance, unsuitable for prolonged high-frequency pulses.
Variable Frequency Motors:
• Coating uniformity & thickness: Thinner, void-free layers via Vacuum Pressure Impregnation (VPI) to prevent partial discharges.
• Higher thermal class: F-class (155°C) or H-class (180°C). Example: Polyimide-coated wires (QY-type) tolerate short-term overloads.
Standard Motors:
• Simpler processes; looser coating tolerances. Thermal classes: B-class (130°C) or E-class (120°C).
Variable Frequency Motors:
• Slot fill optimization: Flat wires (e.g., Hair-pin motors) achieve >95% slot fill, reducing copper loss and boosting power density.
• EM stress resilience: Enhanced mechanical/electromagnetic fatigue resistance for frequent starts/stops and harmonic currents.
Standard Motors:
• Primarily round wires with lower slot fill (~78%); cost-driven designs over high-frequency performance.
• Must endure humidity, corrosive gases, and high-frequency EMI. Often feature chemical-resistant coatings.
Standard Motors:
• Basic insulation suffices for stable environments.
|
Parameter |
Variable Frequency Motor Wires |
Standard Motor Wires |
|
Insulation |
Polyimide composites, corona-resistant additives |
Polyester, polyvinyl acetal |
|
Pulse Resistance |
High (200× improvement) |
Low |
|
Process Complexity |
VPI, strict coating control |
Conventional dipping |
|
Thermal Class |
F/H-class (155–180°C) |
B/E-class (120–130°C) |
|
Applications |
Inverter-driven, high-frequency (elevators, EVs) |
Stable grid power, constant loads |
.
• For VFD Motors: Prioritize corona resistance, thin-film precision, and thermal resilience.
• For Standard Motors: Focus on cost efficiency and baseline performance.
Emerging Trends: Nano-coated wires and self-healing insulation materials are gaining traction for next-gen VFD applications.
(Technical terms like "corona resistance," "VPI," and "slot fill" are standardized in IEEE/IEC nomenclature.)
Need deeper material specifications? Consult electric motors manufacturers for tailored solutions!
