What is the most likely cause of high amp draw in a newly installed fan motor?

In the case of a newly installed fan motor exhibiting high amp draw, the most likely cause is a defect in the fan motor itself. A defective motor may have internal issues such as short circuits, mechanical binding, or problems with the windings. These issues can result in increased resistance, causing the motor to draw more current than normal.

When a motor is operating correctly, it should draw a specified amount of current based on its design and load conditions. If the motor is defective, the extra current draw can lead to an increase in operating temperature, potentially causing further damage to the motor or even a trip on overload protection devices if the situation persists.

While aspects such as improper belt tension or insufficient horsepower can affect motor performance, they are less likely to be the primary reason for high amp draw in a newly installed unit. A tight belt can indeed increase load on the motor, but if the belt was adjusted correctly during installation, it should not cause abnormal amp draw alone. Similarly, a motor with insufficient horsepower would generally struggle under load but would not necessarily show high amp draw unless it was beyond its rated capacity.

Overall, the presence of a defect in the fan motor represents the most straightforward and indicative cause of high current draw in this scenario.