The answer to this question appears at the end of this newsletter.


Repair Logs
How many times have you done the same repair on the same equipment? Above, we talked about using repair logs to show others why equipment fails as part of getting people behind the maintenance effort. However, you should also use these logs to analyze equipment history for patterns, because doing so reduces total repair time.

The following are two examples. The first is an example of failure frequency, while the second is an example of dominant failure mode.

• Example 1. The main drive motor on Extruder Four failed due to voltage imbalance four times in the past six months.
• Example 2. Of the last 10 failures on Conveyor 3 so far this year, seven were due to excessive loading.

Some terminals are rated for more than one conductor, but use them only for parallel conductors.


Safety Rules
As kids, we are taught that it's better to listen than to talk. That's generally good advice, but it doesn't always apply to safety. For example:

• Ask if in doubt. If something in a work procedure isn't clear to you, don't guess. Ask someone who is authoritative. Seek a correct answer, not an excuse for unsafe behavior.
• Report problems promptly. Report unsafe conditions to the proper authority, without delay. This helps protect everyone. An unreported safety hazard is unlikely to be fixed and recurrences are unlikely to be prevented.

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Quiz Answer
Answer to Electrical Troubleshooting Quiz
Repair logs don't need to be extensive to be useful, as long as they are clear and factual. In this case, you have enough information to identify a likely cause.

These failures only happen on the second shift. The fact that they happen at the start of the shift indicates that operator does something differently at the start of the shift.

For instance, perhaps the operator is energetic at the start of the shift and wants to speed things along to make better numbers. So instead of sliding the crates of finished pickle jars onto the conveyor, he throws them on there. The momentary pressure jolt overloads the conveyor.

Although this could be a power quality problem, it probably will only appear to be a power quality problem. Discretely observe the operator, and you'll know. You can use a power analyzer to document the pressure shocks -- they will show up as current spikes on the motor supply.