The engine generates power from the fuel source while the gearbox changes and distributes power = torque * speed or t1n1 = t2n2 to the wheel. both the gearbox and the transformer are constant power (v1i1 = v2i2) devices whereas the generator is a variable resource of multiple fuel sources.
- A generator transforms non-electrical (mainly kinetic) energy into electrical energy. it is mainly driven by a turbine (which is driven by water or steam), or by a gasoline engine, etc.
- A transformer transforms electrical energy into electrical energy, changing most of the time of voltage and current, when the electrical energy supplied is not suitable for applications.
F.i. when you need 3x400v at home to drive a big motorcycle, but you only have 3x230v inventory . You can use 3x230v 3 phase transformer to 3x400v
Most transformers in residential use are used to get low voltages. Doorbell requires 12v. You can use a single transformer 230V to 12V for it.
P.s. the power (p) of both generator and transformer is expressed in va (volt-amp * res) and for the generator the amount of power it produces, whereas for the transformer the amount of power is subject to change. the power delivered to the transformer is almost the same as the power delivered by it.
A transformer is a device used to increase or decrease the voltage supplied when a generator generates a voltage or essentially converts mechanical energy into electrical energy.
Both work on the principle of electromagnetic induction.