Sorry, but that diagram is still rubbish! The rectifier bridge will cause the motor to run in one direction whatever the reversing switch does!
If you want to add "kickback" diodes, the easiest is a rectifier bridge at the relay with "+" and "-" connected to the 12 V supply and the "~" terminals to the actuator connections.
Not sure what the intention of that diagram is, but it has nothing whatsoever to do with what I was explaining about using a bridge rectifier as a convenient form of voltage limiting for the relay switching.It is in fact, nonsensical!
The two SPDT relay control approach is extremely elegant as it uses only single pole relays and one per direction. It does however cause full dynamic braking. If you wish to avoid this, you can add diodes to the NC of each relay (and then implement dynamic braking by actuating both relays together).
Joat ------ there is a heap of circuits and information out there - involving DC motors - particularly brushed DC motors, with driver circuits all involving features such as flyback diodes. Just check out this one of many links on the internet ---- (click here) ..... that could help point out the benefit of flyback diodes for this sort of DC motor driving application involving switching.
That actuator should not need protection diodes as it is loaded, so the load is absorbing energy.I'd go for about 1000uF 12V on the 5V side at the relay board.
Paul--B, In the case of controlling a linear actuator, is there any reason why full dynamic braking is undesirable? If so, would I need to add diodes to the NC of each relay in addition to the bridge rectifier?
Paul__B overlooked something with his circuit. He originally thought that the configuration he presented (provided) has flyback-diode (kickback diode) functionality. But it doesn't.