Variable frequency drive Monitoring of service interval

During operation of VFDs, mechanical and electrical components are exposed to wear and tear. The service interval remaining until the next service (percentage of maintenance interval) of the following components can be monitored:

• DC-link of variable frequency drive
• Fan of variable frequency drive

Maintenance Note
When the service interval until service has expired (value 0%), the variable frequency drive can indicate via the parameter. The behavior can be set up. The service interval remaining until service can be displayed via VFD parameters. Service is required as soon as the remaining service interval until maintenance has expired (value 0%). It must also be checked if the VFD component must be replaced.

I: DC-link

Signalling when service is required
The DC-link of the variable frequency drive is equipped with electrolyte capacitors. The service interval for electrolyte capacitors is mainly defined by the temperature. In high temperatures the electrolytic liquid will evaporate, which reduces the capacitance of the capacitor. The temperature inside the electrolyte capacitor depends on two factors: the ambient temperature and the internal heating caused by current ripple. The temperature of the electrolyte capacitors is measured by a sensor, so that high ambient temperatures are taken into account for variable frequency drive service interval calculation.

Operation Mode Service Interval DC-link
Via parameter Operation Mode Service Interval DC-link, you can set how the warning is to occur when the VFD remaining service interval until service has expired. The information can be indicated in a parameter or a service message can be output.

Service Interval DC-link
Parameter Service Interval DC-link indicates the service interval remaining until next service in percent. If a value of 0% is displayed, service is recommended. It should also be checked if the drives component must be replaced.

Note
High ambient temperature and variable frequency drive is not in operation:
Even with the variable frequency drive switched off, the electrolyte capacitors may age due to high ambient temperatures. The times at which the variable frequency drive is switched off are not considered in the calculation of the time remaining until next service. As a result, the indicated service interval until next service may be too long. The remaining service interval until service is an estimated value.

II: Fan

Signalling when service is required
The variable frequency drive service interval remaining until service of the fan largely depends on the wear and tear of the bearing components. For this reason, the service interval remaining until service depends on the speed and operating time of the fan. The VFD service interval remaining until service is calculated from these two values.

Operation Mode Service Interval Fan
Via parameter Operation Mode Service Interval Fan, you can set how the warning is to occur when the VFD remaining service interval until service has expired. The information can be indicated in a parameter or a service message can be output.

Service Interval Fan
Parameter Service Interval Fan indicates the VFD service interval remaining until next service in percent of maintenance interval. If a value of 0% is displayed, service is required. It should also be checked if the VFD component must be replaced.

Note
The variable frequency drive service interval remaining until service is an estimated value. The service interval actually remaining until next service also depends on the ambient conditions, for example. As a result, the VFD indicated service interval until next service may be too high. Service the fan regularly.