AC Induction Motor. You can get a detailed explanation regarding this in BL Thereja's Electrical Technology-2. 

This is a commercial transformer used in power supplies. I have used such transformers only. The red wire pair shows primary winding whereas the black shows secondary winding. 

A Electro-mechanical Relay. It is quite similar to those I used in the June2005 project, Door locking system. 

A current Transformer, using Toroidal core. 

A Real Transformer

Transformer concept