Motor relay protection

We have four independent DC motors (one on each corner) that is lifting a cart off the ground. These motors are controlled by a PLC. They go on and off and reverse direction as needed to keep the cart moving up or down in a "LEVEL to EARTH" manner. The ice cube relay contacts arc and weld together which causes the lifting mechanism to lift incorrectly. The relays are configured in a H bridge design. There are no arc suppressors on this system. I have been reading online but there are so many different ways to suppress the arc I am not sure which way to go. There are RC snubbers, diodes, TVS diodes, flyback diodes, zeners. I am trying to protect the contacts on these ice cube relays. The motors are 24 volt dc motors. I have measured the maximum current over 11 amps or more at times. These ice cube relays are rated at 15 amps max but I know the motor spikes over that sometimes. What type of arc suppression should I use for these unidirectional 24 volt dc motors?

There are a few solutions:
1.You can use four diodes for every motor, two connecting every wire from the motor to the plus of the power supply (the arrow to the plus) and two from the minus to the motor wires (arrow to the motor).

2. Use a 30 Volt surge protection on the motor wires.

3. use a bidirectional soft start replacing the relays.

What is the current when the relays are being disabled? That is what can kill the relays as when the contacts open, the inductive current will try to make the voltage "infinity", hence some arcing will occur. If the current is too high, they will eventually be welded together.

On my CNC controller board, I use a 250V varistor since this is the largest voltage I will see on systems of this nature. I imagine a 24V varistor should do the trick in your case.

BTW, have you considered an integrated H Bridge to do this? There are H Bridges out there which have all the protection you can possibly need for an application like this. DRV8432 comes to mind. It can do up to 25A if bridged in parallel.

I think your job is of to rotate a dc geared motor bi directional. the same problem. I have faced i one company after doing every possible thinghs after a period of one month I have replaced my plc with a small circuit and all the problems was solved. the problem was dc motor was drived by a vfd throuh relay. the relay was connected to a plc.
when we give a command to a plc a huge spike comes and results a plc malfunctions.

My old school thinking would be that a can type capacitor from the power lead to ground would be give the power somewhere else to go instead of jumping the gap, the bigger the capacitor the better. That fix is comparable to a bandage on a wound since DC is so much more prone to arcing, the relays should also be derated by at least a factor of 2, so if you are actually measuring 11 amps the minimum size relay should be 22 amps. 25 to 30 amps rating would probably assure good service life.

You might want to look for ice cube relays with blowout magnets. the magnets pull the arc to it and the arc then is diminish. Bob