How to Maintain a Variable Frequency Drive

variable frequency drive has been widely used in many areas. However, do you know how to maintain a VFD? In this article, we will show you 10 important tips about VFD maintenance. If you pay attention to these tips, the service life of your variable frequency drives will be extended for a long time.

1. Installation

The VFD should not be installed on a vibrating device, or the main circuit connection screw is easy to get loose. As our technical support said, there are a large number of VFDs are damaged because of this reason.

2. Wiring

It is recommended to install an air switch to protect the current value (should not be too large), so the burnt would not be too serious if short circuit happens. The "N" end should not be grounded. Besides, the control line should not be too long, or the control panel will be interfered by the electromagnetic wave what often leads to malfunction and damage. Shielded wire is suggested if the control line is more than 2 meters. Large current yet regular running contactor should not be equipped beside the VFD, because it brings large interference, leading to malfunction.

3. Braking unit

It is recommended to use additional brake or mechanical brake to achieve frequent emergency brake. Otherwise, the inverter would be often impacted by the electrical counter electromotive force that the VFD would have a high failure rate.

4. Cooling fan

If the VFD driver is often running at low speed under 15Hz, it is recommended to add a cooling fan to the motor.

5. Mounting position

Dust and humidity is the most lethal killer to a VFD. Therefore, it is suggested to install VFD in an air-conditioned room or in an electric cabinet with a dust filter. The dust on circuit board and radiator should be cleaned regularly. After a long period of downtime, it's recommended to blow the circuit board with a hair dryer before connects it to the power.

6. Regular check to cooling fan

In order to prevent VFD from being damaged because of overheat, so we must check the cooling fan periodically. The cooling fan should be replaced when it makes noises. Please see the tutorial about how to replace VFD cooling fan.

7. Power supply

As some factories use generator for power supply, so the VFD is opt to get damaged because of voltage instability. In case like this, voltage stabilization or overvoltage protection device is required in order to protect the VFD.

8. Lightning protection

Although it's a rare occurrence, it's very important. When the VFD is struck by lightning, it will bring heavy damage to it. The VFD for constant pressure water supply system is most likely to be struck by lightning as it has a thunder leading pipe in the sky.

9. Prevent electromagnetic interference

In order to prevent electromagnetic interference, the input, output and control lines should better use shielded wire and the wiring method should not be wrong. If the wiring method is not correct, it will have contrary functions. If it's possible, please wrap it with iron tube with a filter which is used to lower the carrier frequency.

10. Repair

When the VFD is broken, please do send it to an experienced engineer for repairing. An engineer who has no experience may make things worse. If the VFD is in warranty, please do send it back for maintenance.

You can also get to know about VFD drives troubleshooting guide. If you need more information about how to maintain VFD, please contact our technical support.