Here are your parts
Model DWU9302AAB

Here is a service manual although your unit is not listed it should be close
http://www.servicematters.com/m...ibrary/docs/16007823.pdf

I noticed a sparking in the motor relay, and a little smoke emitted....is this normal ?
No

Also, the motor sounds noisier than normal. Could the two be related ?
Yes

At minimum you will need a new relay. Bad arcing will result in contact failure. Also have to find out why the motor is noisy.

Could not find info on what the motor's windings should read for resistance.
I would check it with a meter between each winding and to the case, perhaps a winding has shorted to another in the motor.
Manual does have amperage readings but most people do not have a meter to read this.
Also open it up and check that the motor is not jammed, bearings shot etc.