24VDC's 0V common with 160VDC's 0V

[rainman]

I would like to do up the above. Any things that I would need to look out for.

Basically I will have 2 DC 24V relays. 1 relay for moving forward and the other for reverse.

Main thing here is I wanted to check for over current,
which I put in a fuse and upon fused, the PLC input would have notified.

[HillBilly]

The problem I see is when your fuse blows the 160VDC will be applied to your PLC input through the low resistance motor winding. Idealy you would need an overload block with an auxilary contact.

Darek

[lerman]

The way it is show, both relays will run the motor in the same direction. If you had it wired correctly, you would have a problem if both were actuated at the same time.

If the fuse blows, the PLC will see the 160 volts. A series diode could prevent that.

I suggest using three relays.

One would be a direction relay. In one position, it would be forward; in the other, backwards. It would be a double pole, double throw relay.

The second relay would be the motion relay. When actuated, it would cause motion in the selected direction.

The third relay would be the blown fuse relay. It would normally be actuated by the through the fuse. When the fuse blows, the relay would drop out and its contacts would be sensed by the PLC. Ideally, the fuse would be in the high side of the 160 volt power, but that would necessitate a 160 volt relay. If you want to fuse the low side, put a diode in series with the relay so that it is actuated by (say) a 12 volts supply, but the 160 volt supply is blocked.

Ken

[NC Cams]

We used basically the exact same circuit to make a reverseable winch - only we used 4 "ford type" remote NO starter relays instead - two opposite diagonals were connected to run in an H bridge ran the motor FWD when you engaged those relays and the two in the opposite diagonal engaged to run the motor in REV. When neither diagonal was engaged, the motor sat idle.

By moving the fuse to the motor/switch side of the junction of the OVDC and PLC ground junction, you'll fuse the line in a way that you won't open up the ground and dump all the current thru the PLC ground side when/if you blow the fuse.

By using 4 separate relays, you can shut off ALL current simply when the relays go into a NO condition. If you use a NO/NC system in your device, the motor will ALWAYS try to run in one direction or another when the solenoids are disengaged.

[Al_The_Man]

I would go along with Darek, an overload with aux. would do it.
If your DC common (0) is grounded, it is not good practice to fuse the common side.
Another way would be to use your reversing relays the way you intend and wire a 110vdc relay across the fuse, these are typically 11k coil resistance for Omron LY style, which in no way would pass enough current to rotate the motor, or the relay could latch and retain itself and cut the motor power off all together, and a separate contact feed the PLC input.
Al.