This page should refer to the Removed Forestry Electrical Engine but may sometimes refer to the the Transformers' mod (Link to wiki page) Electrical Engines.
The Electrical Engine is a buildcraft style engine added by the forestry mod that is powered by EU from Industrialcraft 2. The engine uses 6-EU/t to produce Buildcraft power (Minecraft Joules or MJ) that is used with pipes, buildcraft pumps, quarrys etc.
In respect to power, it is almost as powerful as a steam engine when it comes to the amount of power it can generate. Running more than 1 electrical engine off the same circuit/wire seems to be a problem however, since it will usually stop current from flowing to both engines. These kinds of engines also appear to significantly drain energy when powered by a storage unit, the engine takes 6EU/t, consuming much more energy than expected.
The Electrical Engine can be used as a power converter between Industrialcraft and Buildcraft. This will only work one-way: by having the electrical engine pump into conductive pipes. This means that Industrialcraft power can be used with Buildcraft machines with a high-rate of efficiency. They can also pull a full stack of items from a machine through a pipe, compared to the redstone engine, which only draws one item at a time. This makes them useful for times you want a stable, non-explosive engine, but need something more than redstone.
Main article: Electric Engines
In the latest recommended version of the Technic Pack (MC 1.4.7), the Transformers Mod was added which has four types of electric engines, Slow Electric Engines are the equivalent to a steam engine, Regular Electric Engines are the equivalent to one Combustion Engine, Fast Electric Engines are the equivalent to two Combustion Engines, and Adjustable Electric Engines can be adjusted, using as little as 2.5 EU/t (1 MJ/t) to as much as 2047.5 EU/t (819 MJ/t). When this engine is set to the highest setting, it will appear as if it is not moving at all, which can be a bit of a problem.
- Energy for more information about different types of energy.