The PowerFlex 700 drive communicates particular problems within the system resulting from factors such as corrosion, loose connections and seized cooling fans. Understanding why faults occur can help your company find the root of the problem.

  Bound and excess loads can lead to overheating and other issues within your company’s Allen-Bradley PowerFlex 700. An extensive list of possible faults that can appear on the unit’s display screen include:

• Drive OverLoad
• Excessive Load
• Heatsink OvrTemp
• HW OverCurrent
• Load Loss
• Motor Overload
• Motor Thermistor
• OverSpeed Limit
• Shear Pin
• SW OverCurrent
• Trnsistr OvrTemp

  If the unit experiences a high load, it can indicate a mechanical binding. Running the load only a few revolutions faster can overload the drive and cause complications like an overcurrent fault.

  First, check the PowerFlex’s load requirements before operating. If you receive one of the fault codes, start by looking for excess load and reduce it as necessary. Also, make sure to uncouple the load from the motor if the motor isn’t up to speed during Autotune.

   Another step you can take is to confirm the connections between the load and the motor. Any form of excess load can cause the drive system to overheat. Check each component before startup by unloading any load conveyors beforehand.

Additional prevention and repair methods include:

• Avoid using wet components
• Clean out the clogged pumps
• Inspect the fans, pulleys, gears and worn components

  You can also use an extended acceleration rate to reduce the high starting load. The extended acceleration will start the load slowly through a progression, rather than forcing it to start up right away.

If the drive's load center has extensive damage, you can replace it to keep your operations running.

Contamination

Often, PowerFlex 700 fault codes that designate contamination within the AC drive relate to overheating. Several fault codes that may appear on the screen include:

• Cntl Bd Overtemp
• Heatsink OvrTemp
• HS Temp Imbal U
• HS Temp Imbal V
• HS Temp Imbal W

  Contamination is a buildup of dirt, dust, moisture, oil, metal particles and other debris that can be electrically conductive. One of the worst-case scenarios that can happen is if oil or other fluids cover your system. A buildup of pollutants over time prevents steady airflow through the system, causing excess heat to form.

  The system has vents, cooling fans, heatsinks and other components to allow heat to dissipate. If contaminants clog any of the parts, they prevent the unit from adequately cooling. Excess heat buildup can cause the mechanical and electrical components to break down, causing failure.

  Accumulation can also create stray current paths. For example, if you see tracking marks across the circuit board or other components, it can be a sign of contamination failures. If the Powerflex system is open to excessive contamination, your operations will need to isolate the drive from the contamination source. If this prevention isn’t possible, you can also put an enclosure over the unit.

  The first step in controlling contamination buildup in your company’s AC drive is to disconnect the unit’s power. Then, check heatsink and cooling fans for contamination. Remove any obstructive objects, dirt and metal shavings by using compressed air. The force of air will eliminate the buildup from the entire system, instead of spreading it to other areas of the drive.

  It’s also crucial to adhere to a regular cleaning schedule. On top of cleaning the heatsink and fans, make sure to clear out the vents as well.

  If the buildup of contamination is too extensive, your establishment can send the PowerFlex 700 in for servicing by the professionals.