If you sketch out the circuit of a bridge rectifier converting ac to dc for a coil you can see that the bridge ends up with an arrangement that is two series diodes and the pairs of series diodes are in parallel. My ascii art isn't up to drawing this, but you end up with an "equivalent" circuit that is how a normal diode is wired across a coil.
In a solid state circuit the back emf diode protects the switching device - the transistor, but in an EM I don't think you need to protect anything.