1. Bearing failure.
2. Air Gap: Between the outer plate (hub) and the belt/rotor (.016 -. 030 inch) Note! Air gap varies with compressor type - check OEM specs.
3. Shorted Coil - Due to improper polarity or weak/burnt winding.
4. Low voltage at coil will cause coil to overheat due to slippage.
5. Locked Compressor: Excessive discharge pressure - Check for restricted condensers, receiver/driers or an oil over charge
6. Belt is wrong type, wrong size, miss-aligned or loose.