Danfoss FC-302 frequency converter display W 66 fault repair

The Danfoss FC-302 series is a multifunctional frequency converter, which means that the entire operation process from standard to servo in any machinery or production line is controlled by a frequency converter. Compact in appearance, diverse in packaging forms, safe parking function, intelligent refrigeration system, rich built-in components, standard communication configuration, widely used in various fields such as food, beverage, printing, papermaking, petrochemical, textile, steel, machinery, lifting, elevator, building materials, HVAC, etc.

Yongsen Intelligent received an FC-302P3K0T5E20H1B Danfoss frequency converter at its offline store. According to customer feedback, the FC-302 Danfoss frequency converter displayed W66 fault as soon as it was powered on.

Inspection process:

FC-302P3K0T5E20H1B Danfoss inverter 3KW, with a packaging level of IP20. The disassembly and assembly of this box type frequency converter is very simple. According to the customer's feedback, we will immediately start inspecting the frequency converter. First remove the operating LCP panel, then remove the cover plate, and you can see the control card of the FC-302P3K0T5E20H1B frequency converter. First remove the control card, then remove the side panel, remove the cooling fan, and remove the power card. After removing the power card, it was found that the rectifier module, frequency conversion module, electrolytic capacitor, switch power supply, and drive circuit on the power card were working properly. However, the power transmission shows W66 malfunction. W66 fault explanation: The temperature of the heat sink is low. The radiator temperature of the FC-302P3K0T5E20H1B Danfoss inverter is displayed as 0 degrees.

Fault analysis:

According to the fault explanation of FC-302P3K0T5E20H1B Danfoss frequency converter W 66, there may be two possible reasons for the fault displayed on FC-302P3K0T5E20H1B Danfoss frequency converter, 1. Temperature sensor and 2. The detection circuit of the temperature sensor. Check if the temperature sensor is integrated into the IGBT module, which is easy to measure as long as the resistance value is detected. After inspection, it was found that the temperature sensor is in good condition. So it is only believed that it was caused by damage to the detection circuit.

Why is the frequency converter damaged like this? The maintenance personnel immediately inquired about the environment in which the customer was using the site, and the customer stated that there was some dust and humidity on site during this period. The maintenance personnel immediately inspected the fan and found a large amount of oil stains on the cooling fan of the FC-302P3K0T5E20H1B Danfoss inverter. It can be inferred that the oil stains caused the damage to the FC-302P3K0T5E20H1B Danfoss inverter.

Repair process:

Replace the damaged components of the temperature detection circuit of the frequency converter, and install the power card, bottom plate, side plate, control card, upper cover plate, and operation panel of the frequency converter in sequence. Check the diode characteristics and ground insulation of the FC-302P3K0T5E20H1B Danfoss inverter to ensure they meet the power transmission standards. Power on the frequency converter for inspection. After passing the self check, measure the power supply voltage on the input side to balance the voltage during startup and output. Input and output current balance for load measurement,

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