Common Sense Safety

Contrary to popular opinion, all workers can prevent themselves from getting hurt. The easy way to avoid pain is to observe how others have taken risks and been injured, rather than learning the hard way–from your own injury. That’s common sense! By avoiding unsafe acts and practicing common sense, your work will go smoother, with less chance for accidents.

The experts say at least 80% of industrial accidents are caused by unsafe acts on the part of employees–and not by unsafe conditions. Although employers are required by law to provide a safe and healthful workplace, it is up to you to be aware of your work environment and follow safe work practices. Statistically, most accidents are caused by unsafe acts, including:

Being In A Hurry – Sometimes there is more concern for completing a job quickly instead of safely. Take time to do a good job and a safe job.

Taking Chances – Daring behavior or blatant disregard for safe work practices can put the whole work team at risk. Follow all company safety rules and watch out for your fellow employees. Horseplay is never appropriate on the job and can lead to disciplinary action.

Being Preoccupied – Daydreaming, drifting off at work, thinking about the weekend, and not paying attention to your work can get you seriously hurt or even killed. Focus on the work you are paid to do. If your mind is troubled or distracted, you’re at risk for an accident.

Having A Negative Attitude – Being angry or in a bad mood can lead to severe accidents because anger nearly always rules over caution. Flying off the handle on an outage is potentially dangerous. Keep your bad moods in check, or more than one person may be hurt. Remember to stay cool and in charge of your emotions.

Failing To Look For Hidden Hazards – At many jobsites, work conditions are constantly changing. Sometimes new, unexpected hazards develop. Always be alert for changes in the environment. Hidden hazards include spilled liquids that could cause slips and falls; out-of-place objects that can be tripped over; unmarked floor openings one could step into; low overhead pipes that could mean a head injury; and other workers who don’t see you enter their hazardous work area.

Remember to stay alert for hazards, so you won’t become one more accident statistic: You can do a quality job without rushing. Maintain a positive attitude and keep your mind on your work. This is just common sense–something smart workers use!

Copper Resistance Testing

General. The typical generator stator winding consists of three independent circuits or phases. These circuits must be as symmetrical as possible with one another to achieve maximum generator efficiency. This symmetry includes the cross section of each conductor as well as the length or distance from main lead to neutral lead. The Copper Resistance (or Winding Resistance) test measures this “distance” for proper length and high resistant anomalies (i.e. cracks, shorted turns, open circuits, etc.). An increase in resistance from one test to another could indicate the potential for a future winding failure.

Test Setup & Execution. The main and neutral lead connections should be broken and open. The lead ends should be free and clean of surface contamination so that the test probes make good contact. Copper resistance testing is performed with a Digital Low Resistance Ohm Meter (DLRO) test set. The DLRO instrument is extremely sensitive. Poor contact and circuit set-up can either produce erroneous readings or no readings at all.
One probe of the DLRO is connected to one lead of an individual phase, and the other probe connected to the other lead of the same phase. A reading (generally to the fourth decimal place) in ohms resistance is measured and recorded. This same process is repeated on the second and third phase. The ambient air temperature and humidity should be recorded as well.

Interpretation of Results. Temperature significantly influences the resistance of a dielectric as well as a conductor. For this reason, the copper resistance measurement should be corrected to standard (typically 40°C).
The original equipment manufacturer normally records and documents the as-built phase-by-phase copper resistance measurements. These are used as the baseline by which all future readings can be compared.
An increase in in copper resistance indicates the presence of some form of high resistance issue (i.e. broken conductors, cold braze joints, turn-to-turn shorting, incorrect connection, incorrect number of turns or stranding, open circuit). Additional testing will be required to determine the specific cause of the variant reading.

Standard. IEEE Standard 11 8TM-1 978, IEEE Standard Test Code for Resistance Measurement.

Test Equipment. A Megger, Model DLRO-10 or comparable is recommended. Kelvin and Wheatstone bridges are also used to measure resistance.