Starting with he electric itself.
1. Pull the electric cord from the socket and see if there is evidence of a short circuit. Look at both of the flat prongs to see if they have burn marks.
2. With the electric disconnected remove the cover from the electric terminal block. See if there is any shorted, burnt or loose connections on the incoming power.
Now move on to check for shorts in the system. With the system still unplugged.
1. Check for continuity between the right side connection at the terminal block and any spot on the case of the machine.
2. Do the same for the left side.
If you have continuity between either hot leg and the case then there is an internal short. I would suspect to look first at a short between the heating element and its case. Check for continuity between either heating element connection and its case then the other. If not this may still be the case but the element is not touching the case until it gets hot and sags a little. You can check to see if there is some sagging by pulling of the heating case and look at the gap inside between the wiring and the case.

If not then it might be your motor is going bad and drawing to many amps as it heats up. Do you hear a buzzing or humming sound when you start the machine.

Try these checks and let us know the results.