Upon completion of this module analysts should be able to successfully obtain data from visual inspection of a motor and motor nameplate in order to characterize the motor.

Accessing Motor Nameplate

The motor nameplate is located on the motor itself usually in a location where personnel can read it. You may need permission to access the motor nameplate. Ask the facility contact if you can have someone escort you to the motor, or ask if it is ok to go there alone. You may need the following tools while accessing the nameplate: Ladder, Camera(Phone), and a brush. It should be noted that there are inherent safety risks when accessing motor nameplates. Refer to the Industrial Assessment Safety chapter.

The information typically found on the motor nameplate includes the following:

  • Rated Horsepower(or power in kW) - This is the nominal horsepower is sized to handle (Note that the motor's actual horsepower output and associated electrical draw is typically different and dependent on the load it is connected to.)
  • Rated Voltage (possibly listing 2 different voltages depending on how it is wired in)
  • Full load amperage (possibly listing 2 different amperages depending on how it is wired in)
  • Full load speed (FLRPM) - this is the RPM the motor will slip to under full load. For instance a nominal 1800 RPM motor might slip to 1765 RPM at full load.
  • Service Factor (SF) - This is the fraction of the motor's nominal horsepower that it can handle without ill effect. For instance a nominal 100 HP motor with a 1.15 Service Factor can handle a 115 HP load. 
  • Enclosure type
  • Frequency

The following information may also be included

  • Full load efficiency
  • Power Factor (PF)

Power supply type

Sometimes this is indicated with the Greek letter ϕ, or with the abbreviation "PH". Example: 3 phase is represented by 3ϕ.

  • Three phase- commonly used in commercial or industrial facilities for its power density and flexibility. 
  • Single phase- common household power circuit.
  • DC- this is direct current. It is rare to see this powering a motor while on an assessment. However, some older facilities may have a DC circuit for a VFD.


Enclosure Type (Visual Inspection)

Make a note if motor is vertical shaft, due to extra costs (standard horizontal motors cannot be mounted vertically since different bearings are needed).




TEFC - Totally Enclosed Fan Cooled

This type of enclosure is more common in environments with contaminants (dust, humidity, drips, etc.) that could harm the motor.




ODP - Open Drip Proof

This enclosure type is open to the environment and should not be used in high contaminant facilities however these motors typically have laminated windings and sealed bearings to protect against contaminants. They tend to be more efficienct than TEFC motors because of the open cooling.

Drive Type (visual inspection)


Direct drive - This means no reduction from gears (no belts,chains, etc.)




High torque drive belt - Looks similar to car timing belt

 




Standard v-belt - These belts are wider in the external perimeter. The next is a cross-sectional diagram of a standard v-belt.

 




Notched v-belt - These belts are a combination of high-torque belts and v-belts. Compared to the previous 2 belts, the advantage of this type is that it takes less energy to bend due to the notches.

Gearbox - on occasion, equipment might be connected to motors via a gear box that might reduce or increase the RPM. 

 

Nameplate Example

  • Row 1 is the highest output, talk with facility personnel to see what the motor is normally operating at or check datalogs after the assessment.
  • Row 2 is a secondary operating condition, make sure to check with facility personnel to ask the standard operating conditions. Motors are rarely run at 100% capacity all of the time.
    • Column A) Rated HP (NOT brake horsepower). Brake horsepower is a function of the load put on the motor. You cannot know the brake horsepower by looking at the name plate. 
    • Column B) Rated Voltage. There is a slash seperating two numbers to indicate this motor is dual rated, it can run at 230V or 460V.
    • Column C) Full load amperage
    • Column D) Full load speed
    • Column E) Full load efficiency
  • X) Power Factor – Not pictured. PF is calculated in the MAT tool. If the nameplate includes it, there is an input for it that overrides the calculation.
  • *NOTE: watch units when looking at nameplates. Some may be in metric and some may be in Imperial. Make conversions as necessary.
  • Other data: Model number (good to have if the nameplate is hard to read), bearing numbers, service factor (may be used to correct the MAT tool if dataloggers are inaccurate).
  • If there is any chance motor may be part of a VFD recommendation, note whether if it is or is not inverter-duty.
    • Has a sticker indicating this
    • Can also be located on top or bottom or nameplate (i.e. not in grid of nameplate)

Here is a video explaining some nameplate basics.

 

https://www.youtube.com/watch?v=oiK09jkRjt8

 

References

"ODP High Efficiency Motors - NEMA Standard - Electric Motors - Products & Services - Belgium - WEG." Change. N.p., n.d. Web. 15 May 2017.

V-Belts;Power Transmission Belts;Synchronous Belts;Timing Belts;Industrial V-Belts;Low Cost;Discount Prices. N.p., n.d. Web. 15 May 2017.

"Margot Machinery: A Used Converting, Paper, Plastics, And Nonwovens Machinery And Equipment Dealer." Used Machinery for the Converting, Paper, Plastics & Nonwovens Industries - Margot Machinery. N.p., n.d. Web. 15 May 2017.