What are the causes of fan coil unit motor burning at the end of air source heat pump?

Last Updated on November 5, 2021 by Shawn Lee

1. wiring error leads to burning, and multiple units are used in parallel

Two or more coil units are controlled at the beginning of the same control, that is, multiple units are connected in parallel. When the motors run in high, medium and low grades, there will be potentials on the secondary phase windings, i.e. red, blue and black. Different motors have different potentials on the corresponding color lines. If they are forced to be connected together in parallel, current will flow from high potential to low potential, forming a circulation between the motors, resulting in higher temperature rise of the local windings of the motors. In severe cases, the local windings of the motors will burn and the motors will stop running. This burnt-out motor forms a short circuit to the corresponding motor local winding, which will soon lead to the burning-out of another motor local winding. Similar situations will occur for units of the same model due to different wind resistance.

2. Overall high temperature

The above situation is mainly caused by the following factors:

A: abnormal power supply, such as high voltage and unequal frequency;

B: abnormal load, such as the size of air duct and air return box does not meet the requirements, and the wind wheel changes;

C: locked rotation, e.g., wind wheel stuck, etc.

3. turn-to-turn burning

Turn-to-turn short circuit is mainly caused by the damage of paint film.

The factors leading to turn-to-turn short circuit are:

A: there are many pinholes in enameled wire;

B: the paint film is damaged when the stator is wound around the embedded wire;

C: When using, foreign objects poke into the stator, causing damage to the enameled wire.

Third, the inspection process

When the motor does not run, check as follows:

1. Check whether the controller and power supply are normal;

2. Check whether external factors such as air ducts meet the installation requirements;

3. check the motor resistance and unit wiring;

4. Check the stator condition after the motor burns down, and judge according to the above reference.

5. The burning phenomenon is that the vice phase burns black and the main phase is normal, so the unit wiring should be checked. If necessary, the unit wiring of the whole project should be checked.


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