I spent last few weeks troubleshooting an RO system in our lab. I finally got it working today after replacing a number of parts.

The question is this: one of the parts I replaced was a pump, both the motor and the pump head. The pump head was practically seized from brown sludge accumulated from water. I did not chance leaving same motor in. After that, it also turned out that the fuse on the board powering the pump was blown. I just would like to confirm my assumption that a motor would draw excess current as it is "trying" to work harder.

I have been getting conflicting information throughout my troubleshooting so would like to know that my assumptiin about why that fuse blew is correct.

Thank you

 

Yes, the more power a motor has to generate, the more current it will draw.
If overloaded, it can draw enough current to blow a fuse that is typically rate for current a little higher than the normal running current.
For example, a motor can draw 10 times or more its normal running curren when starting, where it's drawing the maximum load.