Regular maintenance is important to keep a variable frequency drive (VFD) operating efficiently and effectively.

Selecting the right type of VFD for the job is the first step. For outdoor applications such as oil and gas operations, irrigation, wastewater treatment and mineral extraction, the correct NEMA-rated enclosures should be specified to protect the VFD from dust, dirt and debris.

Once installed, the VFD needs to be kept clean, especially in dusty outdoor environments. Some NEMA-rated enclosures require ventilation, and that means fans need to be kept clean and free to operate to avoid a potential fault that could damage the VFD. Air filters need to be cleaned regularly.

Also, regular monitoring of heaters in cold-weather outdoor settings is needed to ensure the VFD and its sensitive electronics remain at the correct temperature.


Don’t overlook the VFD’s wiring, including the wires that lead from the drive to the motor. It is critical to follow local electrical codes to the letter and rely on a qualified electrician or startup engineer to handle the task of wiring.

Failing to take proper precautions when working with wiring can lead to serious injury or death, and may also damage the VFD and the motor. Disruptions are always costly, so it is best to rely on a certified electrician to maintain and repair VFD wiring.

Four elements are particularly critical when looking at a VFD’s power wiring:

  1. The power wires and branch circuit protection going to the VFD should be sized to handle the system’s load, voltage rating and full load amps of the motor being controlled. Wires going to the motor need to be sized based on that current and the voltage they will carry.
  2. When considering cable, be aware of the insulation level needed to prevent electromagnetic interference. Shielded power cable often is the preferred choice for both input and output cables.
  3. Routing should be considered when looking at the drive’s input and output interconnections. Input wires should be routed separately from output wires going to the motor. Common practice is for there to be at least 1 inch in between cables that are run in parallel. If cables must cross, the recommendation is for that crossing to take place at a 90° angle to prevent interference.
  4. Have the shielding terminated on both ends to the ground location for the input and output motor leads. Doing so will keep a common ground throughout the system. Running wiring in a conduit will also provide protection if a shield wire is not provided.

The frequency of your inspections for the VFD wiring depends on the application. VFDs that are installed outdoors for use in oil and gas production may need to be inspected once a quarter. If the VFD is in a building where the environment is less harsh, then a twice-yearly inspection schedule may be enough.

Double-check the VFD’s internal wiring connections prior to the first-time startup. It is common for the VFD to be handled during installation in ways that might loosen connections. Be certain that the electrician or startup engineer checks the connections to minimize the possibility of a failed start.

IER Services offers WorldWide Electric Corporation VFDs to control electric motors that deliver powerful solutions with exceptional speed control and torque response. Products are available as an open drive or closed drive to protect against harsh environments.

WorldWide Electric is the largest independent manufacturer and importer of industrial electric motors in the United States. Their diverse product lines also include soft starters, motor controls and gear reducers.

By |2021-11-29T15:17:19-05:00November 29, 2021|Uncategorized|Comments Off on Regular maintenance is important to keep a variable frequency drive (VFD) operating efficiently and effectively.

Why Do Motors Fail?

Electric motors are complex machines with multiple moving parts. They are vulnerable to  common performance issues that reduce their life span. Everyone wants their motors to last a long time and knowing the problems that can affect their dependability and operation is important. There are six main issues that can result in premature motor failure.

  1. Electrical overload. Excessive voltage supply or overwork by drawing more current will lead to overheating issues. As the motor works harder or under an unusual load, heat can lead to motor failure.

More than 55% of insulating failures in motors occur due to overheating. Several factors that contribute to overheating are poor power quality and/or a high-temperature operating environment. For every 10oc that the temperature of a motor rises, the insulation life is reduced by half.

  1. Low resistance.This is the most common reason for motor failure is usually an electrical issue. Degradation of motor windings by heat will pave the way for short-circuits and leakages, which then result in motor failure.
  2. Contamination. Dust and debris will raise the internal temperature of a motor and keep it from cooling, which leads to excessive heat over a longer period of time. This generally occurs without proper maintenance or venting for particles. Care needs to be practiced in loading grease into guns and the injector tip needs to be protected from dirt as grease can introduce contaminates into bearings.
  3. Start-stop frequency.This plays a big role in heat damage. Excessively starting, stopping, and starting won’t allow the motor to cool properly. Components can be compromised in a high-heat environment.
  4. Vibration.Severe vibrations can raise the temperature to levels that are not safe and can result in components that are stressed beyond their heat capacity. Vibrating motorscan create noise, cause safety problems, lead to degradation in plant working conditions and cause machinery to consume excessive power.
  5. Moisture.Moisture and humidity are problems if a motor is de-energized long enough to drop near the dew point temperature. Moisture weakens the dielectric strength of the electrical varnish and other insulating materials. It also contributes to bearing erosion and other electrical components.

Moisture can be reduced if the motor is kept warm. Motors stored inside should be pre-warmed for several hours before starting. This dries the moisture accumulated in the motor winding. (Space heaters can also be used to keep the motor warm

Motor failures continue to happen until maintenance solves the core issue. a maintenance plan: Thorough, routine maintenance ensures individual components within the electrical system get the attention they need to minimize overwork and overheating.

IER can help you with your commercial motors, pumps and drives. We sell, repair and maintain commercial motors. Call 614-298-1600 to learn more.

By |2021-11-29T15:14:54-05:00November 29, 2021|Uncategorized|Comments Off on Why Do Motors Fail?

Across The Line Motor Starters

The simplest type of motor starter is an across the line starter or a direct on line (DOL) starter. It is also the starter that experiences the highest current during the motor starting process.

These starters apply the full line voltage to the motor terminals. A DOL motor starter often contains protection devices and in some cases, it has condition monitoring. OL starters

An across the line starter can be used if the high inrush current of the motor does not cause excessive voltage drop in the supply circuit. The maximum size of a motor allowed on a direct online starter may be limited by the supply utility.

These starters are can be used with most applications such as when starting small compressors, fans, water pumps, and conveyor belts. They are also considered to be user friendly and cost-efficient.

IER sells a selection of WorldWide Electric and Siemens brand across the line motor starters including definite purpose starters, NEMA heavy duty motor starters, irrigation pump panels, heavy duty combination starters, and solid-state overload relays and control transformers.

WorldWide Electric is a leading manufacturer of quality, affordable electric motors, motor controls, and gear reducers. They are also an exclusive master distributor of Hyundai Electric’s low-voltage electric motors and drives, and following our acquisition of Louis Allis in March 2020, we now proudly offer custom specialty motors and factory re-certified motors too.

If you would like to learn more about across the line starters or any of the Worldwide Electric products, give us a call. Our team can help you determine the best equipment for your job.

By |2021-11-29T15:07:33-05:00November 29, 2021|Uncategorized|Comments Off on Across The Line Motor Starters


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