Use of MCB To protect Dc motor

The following are the most important criteria for selecting the optimal MCB /MCCB for

protecting a DC system:

● The rated current determines the power rating and the frame size of the circuit breaker

● The rated voltage determines the number of series-connected poles required for

switching off

● The maximum short-circuit current at the connection point determines the breaking

capacity

In AC circuits, arc quenching is facilitated by the fact that the current flows through the zero

point. These preconditions aren't true for DC.

For this reason, a high arc voltage must be developed to interrupt the direct current.

Therefore, the switching capacity depends on the arc quenching method and the network

voltage. Several switching contacts can be connected in series in order to achieve a higher

arc voltage.

Furthermore, the kind of effects that are to be expected in the event of a ground fault or

double ground fault must also be taken into consideration.

so you can use same Ampererating of Single pole MCB upto 60V DC and 110VDC for double pole.

3-pole 3VL MCCB can also be used or 3 pole 3RV MPCB can also be used for you application.
if you need cicuit diagram pls refer technical litreture of above two devices.