IS the momentum logic functional?
Yes, it is. Momentum is one of the simplest technical indicators and it is included in the core of the program since 2005.
Momentum calculates the difference between current price and a price n bars ago. It may smooth the calculated line if you provide an additional smoothing period.
You strategy doesn't open trades because the Momentum indicator never reaches 100 on your data chart.
On the other hand the Momentum implementation of MT is not standard. It oscillates around 100 instead of 0.
Forex Strategy Builder Professional provides this functionality with the Momentum MT indicator. It is practically the same, but its values are shifted with 100 units upwards.
If you want matching same visual expression in MT and in FSB, you can use Momentum MT indicator instead of Momentum.
Momentum MT with Level = 100 may work as you expected.
Momentum MT with Level = 100 is equal to Momentum with Level = 0.
There is no explanation why MetaTrader desn't provide the standard Momentum indicator.
Wikipedia: Momentum (technical analysis)
Formula: Mometum(t) = Close(t) - Close(t-n);
Formula: Mometum(t) = 100*Close(t)/Close(t-n);