A DC motor specified max 15V or 18V, 2A, given input by SMPS 24V

You will over load to coils. It will over heat and fail.

You will also overload the SMPS as the motor will take more than the 2A the SMPS can supply.

Mike.
BTW, how can MAX be two different values? Unless, of course, it's two different motors.

MAX could be an unreadable or damaged label.

Pommie said:

You will also overload the SMPS as the motor will take more than the 2A the SMPS can supply.

Mike.
BTW, how can MAX be two different values? Unless, of course, it's two different motors.

Click to expand...

MAX could be a damaged label listing.

15V motor or a 18V motor is not close to 24V supply.
If the motor was 15 and the supply was 18, I would use it but watch for over heating.

About the 2A, we don't know if that is stall current or run current under no load. We need more information. It is too common for someone to find their motor will not start at 2A, but needs 5 or 10A to start.

As a general rule, you will only overload a motor if it exceeds its rated load, or it reaches its maximum RPM.
IOW, if the (generated) BEMF remains close to the applied voltage, the current will be very low.
Starting an unloaded motor at zero rpm and gradually increasing the voltage, results in approximately the same (low) current throughout the rpm range.