Keeping your world up and running.®

Using the Fluke 66 and 68 Infrared Thermometers

for electrical troubleshooting and predictive/preventive maintenance

If you'd known that bearing was about to fail, of course you would have stopped the motor. So often, changes in heat are a key indicator of costly equipment failure – but who has time to take regular measurements? Technology may have the answer. New infrared thermometers sport such high distance to spot ratios that technicians can now accurately measure multiple instruments from the same spot.

Infrared thermometer applications in industrial process maintenance

  • Finding faulty terminations in high power electrical circuits
  • Locating overloaded circuit breakers in a power panel
  • Identifying fuses at or near their current rated capacity
  • Identifying problems in electrical switch gear
  • Monitoring and measuring bearing temperatures in large motors or other rotating equipment.
  • Identifying "hot spots" in electronic equipment
  • Identifying leaks in sealed vessels
  • Troubleshooting steam traps
  • Finding faulty insulation in process pipes or other insulated processes
  • Capturing process temperature readings

Identifying Overloaded Circuit Breakers
Non-contact temperature measurements can make it easy to find a circuit breaker at or near capacity. If you are measuring high energy electrical circuits, use extreme caution and wear proper protective equipment.

  1. Scan the switches in a circuit breaker panel and take measurements.
    Note: If the circuit breaker body is obscured by a cover plate, you may need to remove the plate to gain optical access to the measurement target.
  2. Look for a temperature variation from one breaker to the next. A circuit breaker with a measured temperature of approximately 5 degrees F greater than the other breakers in a panel is likely to be heavily or fully loaded.
  3. An additional test with a ClampMeter can measure the actual current load and help to determine for certain if a larger breaker or rewiring is required.

Finding bad or failing electrical connections
Failures in industrial electrical wiring are frequently caused by loose or corroded terminations and poorly crimped or aging wire connections. These bad connections generally create a resistive connection, and with current flow they generate heat (P = I2R), often leading to open circuit conditions that can cause electrical fires and other safety hazards. Use extreme caution and wear proper protective equipment when working near high energy electrical circuits. A termination that measures 5 degrees F more than similar terminations indicates a connection in need of attention.

The distance to spot ratio compares accuracy to distance. The higher the ratio, further away your thermometer can be from the target and still take an accurate measurement.

Troubleshooting steam systems
Steam is a common source of heating in many manufacturing processes and facilities. Steam can be produced with regular boilers, boilers fired by combustible by-products, or from water piped through by-product incinerators. The steam is then piped, often over great distances, to the process areas for deployment.

Even though the pipes are insulated, the heat of the steam drops over distance, causing condensation. Condensate (water) in the steam lines reduces the effective energy of the steam and can cause difficulties in many steam driven processes. Steam traps are specifically designed to remove condensate from steam lines.

Insulation testing: To check piping and boiler insulation for hot spots, take an infrared survey.

  1. Set the IR thermometer to MAX mode by depressing the MODE button until the lower display reads MAX.
  2. Depress the measurement trigger and scan the insulation on the piping or boiler. The maximum measurement will be captured and displayed in the lower display. An un-insulated area can reveal maximum temperatures of 400 degrees F or more.
  3. Once you've found the hot spot, correct the insulation to reduce heat loss and burn hazard.

Steam Traps: If a steam trap fails while open, it will leak steam, causing an energy loss. If it fails while closed, it won't remove condensate from the steam line, making it inefficient. A faulty steam trap can cost a plant $500 or more per year, and industrial steam traps typically fail at a 10% rate. Since many large process plants have upward of 1,000 traps, they can quickly become a high value maintenance target.

Ideally, the steam trap has an input of steam and an intermittent output of condensate.

  1. To verify whether a steam trap is working properly, measure the input side of the steam trap first.
  2. As you measure from input to output, the temperature should drop significantly.
  3. If the temperature doesn't drop, the steam trap has failed open and is passing superheated steam into the condensate line.
  4. If the temperature drop is overly large, the trap may be stuck closed and is not passing heated condensate fluid.

Tracking motor wear through bearing beat
By regularly measuring motor bearing housings with an infrared thermometer, you can predict when motors need maintenance and optimize their life cycle.

  1. Start with a newly commissioned, freshly lubricated motor and measure the motor bearing housing while the motor is running. Use this measurement as a baseline.
  2. As the motor and its lubrication ages, the bearings become worn and heat-producing friction develops, causing the outside of the bearing housing to heat up.
  3. Take measurements at regular intervals, comparing them to the baseline measurement to analyze the motor's condition.
  4. When the measurement spikes, indicating an overheating bearing, replace or lubricate the bearing housing to reduce the possibility of costly engine failure.