Comparison of 18000 and 18100
The following table gives a comparison between 18000 and 18100. There are some anomalies and these are described in the notes.
| Value | 18000 | 18100 | Notes |
|---|---|---|---|
| Weight (tons) | 115 | 129 | - |
| Turbine horsepower | 10,300 | 9,000 | (1) |
| Power absorbed by compressor | 7,800 | 6,000 | (1) |
| Output horsepower | 2,500 | 3,000 | (1) |
| Number of traction motors | 4 | 6 | - |
| Total traction motor horsepower | 2,500 | 2,450 | (2) |
| Starting tractive effort (lbf) | 31,500 | 60,000 | (3) |
Notes:
- In 18000, output horsepower is 24% of total horsepower and in 18100, output horsepower is 33% of total horsepower. This suggests that 18100 had the higher thermal efficiency but, in practice, 18000 had the higher thermal efficiency. The horsepower figures should, therefore, be regarded with some scepticism.
- Where electric transmission is used, the horsepower of the traction motors is usually 81% (i.e. 90% x 90%) that of the prime mover. The figure for 18100 is therefore about right but the figure for 18000 looks anomalous.
- lbf = pound-force
Read more about this topic: British Rail 18000
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