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5 reasons for variable-speed drive failure

Like all electronic equipment, from time to time a variable-speed drive (VSD) will fail. Here we look at five of the most commons reasons for VSD failure:


If current exceeds the drive’s rated level then the increase in heat will result in component damage. Fuses and circuit breakers are commonly used to counteract this issue.

As with over-current, voltage spikes can be down to human error but may also occur due to lightning strikes. For this reason, over-voltage may sometimes be impossible to avoid.

Ultrasonic vibrations

These originate in the core of components which creates in friction. This generates unwanted additional heat which can cause catastrophic damage to components that are already under strain.

Capacitor wear

VSDs rely on capacitors for a smooth power output at different current levels, but unfortunately these devices have a limited lifespan and will need replacing every 5-10 years. On the other hand, a capacitor does need to be active. This is because it’s similar to a battery in that it needs to go into service soon after purchase or its power will diminish.

Exceeding operating limit

As with any electrical component, using a variable-speed drive beyond its rated level can result in failure. In many cases this occurs as a result of inadequate training or experience. Here at Gibbons we offer comprehensive training with variable-speed drive installations to ensure our clients enjoy the best possible performance from their equipment.

Improper installation

The above issues all occur when the VSD is in operation, but many VSD problems can be avoided simply by getting the initial installation right. There are many considerations when installing a variable-speed drive, including:

  • Heat. A VSD should be situated in an area where the ambient temperature doesn’t exceed 40°C.
  • Moisture protection. Certain industries, such as food production, require regular wash-downs of all surfaces, so drives must be mounted in an enclosure with the appropriate ingress protection (IP) rating.
  • Supply line quality. This should be high enough to ensure a consistent voltage within a range of +/- 10% to avoid trips.

A professional, experienced ABB drives installer such as Gibbons will cover all the bases to ensure your VSD is in the best possible condition from the moment the job’s completed.

So whether you’ve experienced a variable-speed drive failure or are looking for a new installation, call Alan Roberts on 07966 468430 or email for expert advice and a competitive quote.

Variable-Speed Drives

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