Storage Guidelines for Kinetix Servo Drives and When to Reform Capacitors

Summary

Storage Guidelines for Kinetix Servo Drives and When to Reform Capacitors

Question

• What procedure should be followed when installing a Kinetix servo drive that has been in storage for a long time?
• How to reform Kinetix drive capacitors that have not been used in many years?
• When should I reform the capacitors in a Kinetix servo drive?

Environment

Kinetix servo drives that have been stored or shutdown for a long time

Answer

Kinetix servo drives must be stored in controlled conditions to avoid condensation and damage to the internal components of the drive. If excess humidity and large swings in temperature occur during the period of shutdown or storage, moisture absorption into specific electrical components may occur.

• Excess humidity is defined as humidity levels that at any time exceed the product specification of 95%, non-condensing.
• Large temperature swings are defined as the phenomenon where condensation can occur as the air temperature rises rapidly causing condensation to occur, especially on metallic surfaces.

Storage conditions:

Proper storage procedures must be followed to ensure the longevity of the product. The following storage conditions are recommended for storing products for more than 1 year:

• Temperature (ambient): +20…+40 °C (68…+104°F)
• Relative humidity: < 70% noncondensing

In all cases above, the product must not be located in a corrosive atmosphere. For example Hydrogen sulfide, sulfur dioxide, chlorine, ammonia, etc. A study of the type of contamination and methods to avoid equipment damage must be performed if a corrosive environment is suspected.

Commissioning

The following commissioning guidelines are vital to the success of the (re)commissioning process. Failure to follow these guidelines can result in product failure.

Product Examination:

Inspect the product for any corrosion or physical damage. During storage or long-term shutdown, it is possible for condensation to build up. The product should be inspected for any signs of condensation. If condensation is present, do not commission the product and perform the following procedure.

• Place the product in a low humidity environment where the product can dry out for at least 24 hours.

Capacitor Reforming:

DC bus capacitor failure is the most common failure mode when drive products are stored for 2 years or longer. There are chemical processes that occur naturally inside the device over time that cannot be stopped. However, this chemical process can be reversed through the reforming process. For a product that has been stored for more than 2 years, follow the guidelines specified below.

The following guidance will be used to determine if the bus capacitors need to be reformed.

• If an unpowered product has been stored in a properly controlled environment for more than 2 years but less than 3 years, it can be reformed using a less rigorous process. In this case, the product should be powered up to rated voltage for 60 minutes without enabling the PWM. After 60 minutes, normal operation can be resumed or the product can be put back into storage.
• If an unpowered product has been stored in a properly controlled environment for greater than 3 years, it will need to go through the capacitor reforming process as described in QA1944 – Reforming/Testing AC Drive Bus Capacitors. This process is done via the DC bus inputs on the drive.
  • Note: for bus sharing drives which do not have their own DC input, you may need to apply the voltage via the DC bus connector on the converter or capacitor module and the DC sharing system.
  • Tools for completing this reforming procedure can be acquired from Rockwell Automation partner Bonitron. There are two recommended devices:
    • M3628PCF is a manual device with which the user can manually increase the voltage
    • M3628ACF is an automatic unit that the user can program in steps and set the time for each step

After a reforming process is completed, the product may be placed back into storage. When removed later for installation, another reforming process may be required based on the same time schedule from the previous reforming process.

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Source: Rockwell Automation’s Technote database.