10-14-14 current loco testing process

Finding the current standard test plan is very time consuming. Currently what is being tested is as follows:

1. Run a voltage-current scan on my rollers.
The loco has no external load. The only load is the roller friction and the various drag forces in the loco. The process is to set 16 volts and let the unit run for 5 plus minutes. This gets the loco warmed up and everything gets loosed up. The current is recorded when it has stabilized. Readings are also taken at 12, 9, 6, and 4 volts input. Current is recorded when it stabilizes. The 4 volt current is always a number,but the drive may nit be running. I need to check that out soon.

2. Define the lowest voltage that the unit will start with out help.
This takes some time. Currently the speedometer is 4 feet from the stating point. It has to make it through the meter on its own.

3. Define the current and velocity characteristics with voltage.
Repeat the runs at 4,6,9,12 and 16 volts. Record current and velocity at the speedometer location for exact of these voltages. Run a total of three points at each voltage. If the minimum voltage in step 2 is greater than 3.7, then the first voltage in this step should be the mean between the min voltage from step 2 and 6 volts.

4. Define the 16 volt draw bar force & current.
Measure the drawbar force and current at 16 volts three times.

This process takes at least 30 minutes for each engine, the grade and car load testing are not part of this. This time may not be available, particularly on prep-to-ship units.

Today there were five units in that status.

A streamlined set is needed. A design of experiments approach is needed. The math will open several avenues and the total number of points should be less.

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