Running too low on amps is not good for motors either. They can get hot,need more volts, etc.
The led swap can get you an amp or so back. Each bulb has an amp rating (or watt) add them up (watts convert to amp @ X volts, etc) to see how much they eat (watch for decimals). It's that simple. (leds use milliamps)
A motor will also have a "peak amp" reached during starts/accelration/heavy loads/etc. This can be quite high on some, low on others. We often just speak of continuous amps; leave some excess for peaks. (You should only expect to use about 70%-80% of an electrical rating, leave a 20%+ margin for error unless you have big confidence; to account for for quality, and/or heat issues) There was something else too, but fighting spellwreck AND keeping my mind on electrical is maddening today.... sorry.
Anyhow, the new age transformers don't like big peaks. They assume too fast that there is a short. Go easy raising throttles, that should help.
Once at speed the amp use should drop off, however it is possible the back EMF of modern units might cause some variance to that drop off. (? kinda deep/design question)
Sitting down with a meter to watch, and the roster to run can be a very useful learning experience. More useful than explaining some things that really need some experience to get anyhow. Simply read the meter and react to that 
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