In the safety protection system of refrigeration systems, protective devices act like the "immune system" of the unit, silently guarding the safe operation of core equipment. However, in practical engineering, the absence of phase-loss protectors and thermal overload relays leaves many compressors in a vulnerable, "naked" state.The three-phase asynchronous motor, as the power core of the compressor, relies on a balanced voltage supply for stable operation. When a phase loss occurs (i.e., the loss of any one power phase), 

          The current in the remaining two phases will surge to more than 1.7 times the normal value. If a phase-loss protector is missing, the motor will continue to operate under severely unbalanced conditions, causing the winding temperature to rise exponentially.Even more dangerously, the absence of a thermal overload relay removes the system's last line of defense. This device monitors current changes in real time and can cut off the circuit promptly during an overload. Without its protection, a compressor operating under a phase-loss condition can suffer irreversible damage in just 3-5 minutes. 

         The winding insulation breaks down due to overheating, leading to burnt coils and seized components.It is important to note that three-phase imbalance isn't only caused by external power grid fluctuations. Internal faults such as aging contactor contacts or loose terminals can also cause phase loss. These hidden faults can easily be missed during routine inspections without specialized protective devices for monitoring.Configuring protective devices is not an "optional accessory" but an essential requirement for ensuring operational safety. Every press of the start button should be a process guarded by multiple protective mechanisms. Don't let a few minutes of power abnormality destroy your compressor worth tens of thousands.