As already pointed out, the diodes in the photo are not flyback diodes, they are part of a full wave bridge. They are however, exactly the same kind of diodes that would be used as flyback diodes and the full wave bridge configuration provides the same protection
as a standard flyback diode .
Try this: :
Draw a schematic of the a motor with a fliyback diode across it. (like below)
motor ^ <== (flyback diode)
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Now draw a schematic of your motor as it is appears in your photo and rotate it 90 degrees in the clockwise direction and compare it to the schematic of the motor with the flyback diode. You'll see the similarity with the exception that to you it
will look like a motor with two flyback diodes in series wired in parallel with another similarly wired pair of diodes, yet while
the function of two circuits is totally different, (one if provideing back EMF protechtion,the other is rectifying ac ) you will
see that the bridge rectifier diodes provide flyback like protection. The are the same rating, same polarity (with respect to the back EMF) so actually they are providing a dual function.
^ ^ <== (bridge rectifier diode)
| motor |
^ ^ <== (bridge rectifier flyback diode)
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