Large central air conditioning system cabinet maintenance case
Customer: Shenzhen City, a large shopping mall
Name: central air conditioning control system
Model: SIEMENS M430-110KW
W causes of failure: running less than a minute after the alarm
Failure analysis: large shopping malls with the central air-conditioning to regulate the temperature, humidity and fresh air to add fresh air throughout the year, improve the shopping environment. From the cooling water of low temperature of the cooling tower, into the water chiller after cooling pump pressure, take away the heat of the condenser, the temperature will rise, and then was sent to the cooling tower spray, due to rotation of the cooling tower fan, the cooling water spray in the fall, do not break with outdoor air heat wet exchange and cooling, cooling water into the cooling tower water dish, and then again by the cooling pump pressure into the next cycle. Central air conditioning system can be broadly divided into: mainframe, transportation equipment, pipe network, terminal device and electrical system, etc., the host control system is particularly important. Customer‘s electrical maintenance team of engineers contact me to say that the central air-conditioning system for SIEMENS inverter control, is currently identified as the inverter fault. When I arrived at the scene to find the running signal from a Shanghai production of PID control. When start running the frequency converter start minimum lower limit frequency operation. In less than a minute on the jump without a load converter to stop the output. External AC contactor. The direct operation of the transducer without PID table control failure is still. The inverter fault, after the observation of the fault before the AC contactor is disconnected after the alarm, the AC contactor control circuit fault. AC contactor is the multi function alarm output of the converter. The alarm output is short connected to start running everything is normal. It shows that there is a fault in the multi - function output of the frequency converter. Remove the inverter control board to replace the output of the relay after all normal.
Jia Hong Wei maintenance central air-conditioning inverter, PLC controller appears no show, short circuit trip, not automatically change the pump, the pressure is not stable, not refrigeration, alarm failure and other failures can be repaired.
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