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Electric Motor Failures: How to Diagnose

Small DC Motor rotor showing windings — File:Small DC Motor Rotor.JPG” by Jjmontero9 is licensed with CC BY-SA 3.0.

When your electric motor fails, it can be difficult to know why. But there are quick tests you can use to easily diagnose problems.

Make sure to disconnect power from your electric motor before beginning. Power is not required. This step protects you and the equipment.

Motor Identification

Electric motors have a metal nameplate or tag riveted to the outside of the motor housing. This nameplate usually includes a lot of useful information, including

Nameplate for a Reliance Electric Servo Motor

Manufacturer Name. Who made the motor.
Serial Number or Model Number. The model number tells you the make of your motor. The serial number uniquely identifies it.
RPM. Revolutions Per Minute. The output capability of your motor.
Horsepower. A rating of motor performance.
Voltage. The motor’s voltage requirements.
Current. How many amps the motor requires.
Frame Style. The unit’s physical dimensions.
Type. This can include NEMA ratings, cooling indications, etc.

A wiring diagram may also be included on the nameplate. In some cases, this tag will include the unit’s manual identification number, too.

Surface Roughness and Turbine Blade Efficiency

Image of three wind turbines in fog. Wind turbine blade efficiency can be affected by surface roughness. — Turbine blades can lose efficiency if surface roughness becomes too pronounced.

Does surface roughness have an effect on turbine blade efficiency? Before we answer, let’s consider another theoretical.

Have you ever stood at the top of a mountain or hill and felt the wind slipping over the top of the summit around you? If you’ve done this in cold weather, you’ve probably looked for something like a tree or an outcropping to stand behind. Even smaller ones help. Such things act as windbreaks, parting the constant stream of air coming at you and softening it. But when nothing is in the way, air moving over the curved summit can feel like it’s been supercharged. It moves with an impressive ferocity of speed.

As it turns out, turbine blade efficiency acts much in the same way. And any sort of surface roughness acts like those outcroppings: parting, changing, and diverting the oncoming rush of air.

Although turbine blade design helps maintain robust performance under harsh conditions, wind turbine blades will show wear after only a short time. This includes chipping paint, edge erosion, and insect buildup. Offshore wind turbines are particularly susceptible to this wear due to UV radiation, salt spray, and other contaminants.

As this kind of roughness increases on blade surfaces, performance decreases. Performance issues include increased drag and decreased lift.

When roughness becomes more pronounced, some wind turbines may become subject to blade stall. Others may see a significant decrease in annual energy production.⁽¹⁾

While surface roughness is not entirely to blame, such wear may be part of the underperformance issues plaguing many wind farms.

Blade erosion and surface roughness can be checked through regular inspections. This can pinpoint areas needing attention. Maintenance can then restore some original turbine efficiency.

⁽¹⁾ Ehrmann, Robert S., and White, E. B. Effect of Blade Roughness on Transition and Wind Turbine Performance.” United States. https://www.osti.gov/servlets/purl/1427238.

Need more information on industrial turbine replacement parts? We can help with that. Talk to our team today.

Fuji Electric: History

The Fuji Electric Co., Ltd. has been producing electrical equipment for close to 100 years. Established in 1923, the company sprouted from Furukawa Electric and Siemens AG. The company’s name is a portmanteau of the first syllable of Furukawa and the first syllable of Siemens’ Japanese pronunciation, jiimensu.

The Fuji company has manufactured many different products. This includes transformers from as early as 1925. The company started producing rectifiers, turbines, and circuit breakers in the 1930s. Then in the 1950s, magnetic switch components started rolling off their assembly lines. By the 1970s, the company had moved into developing integrated circuits and inverters. Research into solar cell technology began soon after.

In 1935, part of Fuji Electric spun off as Fuji Telecommunications Equipment Manufacturing. Eventually, this became Fujitsu Limited. In 1955, Fujitsu Ltd. was instrumental in creating FANUC. This group of companies created automation products and services using numerical control and servos. Some may be familiar with equipment made by GE FANUC, a joint venture that began in 1982.