It is a motor that can operate at any rotation speed through the input of variable voltage and frequency (AC), considering the cooling ability and mechanical strength according to speed changes. It is also designed to fully satisfy the speed-torque characteristics required by the load.

ㆍThe insulation failure of inverter motors occurs due to thermal, electrical, environmental, and mechanical factors, especially the electrical aspect, which directly affects motor damage and life reduction.

Degradation Factors	Main Causes	Degradation Conditions
Thermal	▶ Motor losses ▶ Cooling degradation	- Changes in appearance (discoloration, cracks) - Changes in chemical properties (water resistance, chemical resistance) - Changes in electrical properties (insulation resistance, breakdown voltage) - Changes in mechanical properties (strength, brittleness) - Dimensional changes (expansion, contraction)
Electrical	▶ Surge voltages generated from inverter power supplies	- Insulation failure due to partial discharge within slots - Occurrence of corona (discharge phenomenon)
Environmental (Chemical)	▶ Chemical substances ▶ Gas, oil, water, etc.	- Changes in mechanical/electrical properties - Corrosion/erosion - Cracks - Dissolution and changes in appearance
Mechanical	▶ Electromagnetic forces during start-up ▶ Vibration/stress/corrosion ▶ Abrasive corrosion	- Delamination - Cracks - Cutting - Corrosion (erosion)

ㆍDischarge Inception Voltage (DIV) Test Results

The inverter-specific insulation system demonstrates excellent insulation performance against surge voltages.

ㆍPartial discharge amount test results (Discharge amount comparison: #1 << #2) Discharge amount comparison

• - The appearance and dimensions of self-ventilated inverter motors are identical to those of this catalog's three-phase, totally enclosed fan-cooled section.
• - If the primary operating frequency (speed) range is outside 40~70Hz, please consult the factory in advance for the selection of a motor specification more suitable for the load condition.