Quick troubleshooting method for chiller (freezing) machine displaying host overload fault

Quick troubleshooting method for chiller (freezing) machine displaying host overload fault

During the use of the equipment, it sometimes encounters such and other failures, among which "host overload" is not very common. We should not immediately think that the compressor is broken as soon as we see the "main unit overload". There are many external factors that can also cause the "main unit overload". Let's analyze it below:

　　The factors that may cause the host to be overloaded are listed, there are roughly the following:

　　1. Compressor mechanical failure;

　　2, compressor motor coil failure;

　　3, the overcurrent protector is defective;

　　4, the compressor AC contactor is bad;

　　5. The compressor load is too large (the compressor load is too large, including: the pressure caused by the poor heat dissipation of the condenser is too high, and the compressor load caused by the high water temperature just after the start of the machine, etc.).

　　 Let’s take a closer look:

　　1) Compressor mechanical failure

　　 If the compressor lacks refrigerating oil or the refrigerating oil deteriorates during use, it will cause excessive wear resistance of the mechanical running parts, mechanical damage will cause the mechanical card master to fail to operate, and the compressor will experience host overload.

　　 Treatment method: Replacing the compressor in these situations is a *good* thorough solution.

　　2) Compressor motor coil failure

　　 Compressor motor coil is out of order, usually because the coil is overheated, causing a local short circuit or overall burnout. An experienced electrician teacher can use a high-precision multimeter to measure whether the coil is burnt out. That is to measure whether the resistance values of the three-phase windings of the motor are equal, and whether the insulation resistance values of each phase winding and the housing are within a reasonable range.

　　 Treatment method: If it is determined that the compressor motor winding is damaged, it can only be solved by replacing the compressor.

　　3) Defective overcurrent protector

　　Each compressor is equipped with an overcurrent protector. When the compressor running current is greater than the preset value (a certain period of time), the overcurrent protector will act and cut off the compressor's power supply. Let the compressor not burn out the motor coil due to other reasons. In fact, the thermal protector is also affected by the ambient temperature (mechanical thermal protector). When the ambient temperature or the temperature in the control box is too high, it will affect the sensitivity of the thermal protector and cause malfunction.

　　Identification method: We can use an ammeter to measure the current when the compressor is running. If the current is within the normal range and does not increase for a long time, it can be explained that the thermal protector is defective (when the set value is correct).

　　 Treatment method: replace the thermal protector of the same model, set the action value and the unit can resume normal operation.

　　4) Defective compressor AC contactor

　　 AC contactor is an important component in the electrical control system, and its quality plays a very important role in the safety of compressor operation. The working principle is not described here. The common problem of AC contactors is that the contacts stick, which makes it impossible to disconnect. If three electric shocks stick at the same time, it is okay, at least it will not cause the danger of the compressor motor coil being burnt due to lack of phase, and at most it will cause the equipment temperature The set value is reached but the compressor still runs without stopping (compressor does not stop). However, if one of the three contacts of the AC contactor is burned, the compressor motor coil will be out of phase, otherwise the compressor motor coil will be burned.

　　Recognition method: If the contact is sticky, it can be found only by visual inspection. If one of the contacts is burned out, it can be easily judged by measuring with a multimeter. It can be done by basic electricians, so I won’t say more

　　 Treatment method: If the AC contactor is defective, the best way is to replace the AC contactor of the same model, the failure can be resolved and the equipment can resume normal operation.

　　5) The compressor load is too large

　　 The compressor load is too large, nothing more than the following problems: poor heat dissipation of the condenser leads to too high condensing pressure, which causes the compressor to operate at overload. It is also possible that the temperature of the water is relatively high just after the start-up, so that it can only be overloaded for a short time.

　　Identification method: Check the water output of the cooling tower and whether foreign matter enters the water pump. Whether the air-cooled condenser has dust or the filter is blocked; whether the air outlet of the water tower is blocked or whether the air outlet of the air-cooled condenser is blocked and whether the installation position is improper.

　　 Treatment method: Follow the above points to find out the cause and deal with it.