creda reservair 37644 problem with the drying process?

I have taken the covers the back off the dryer the dryer runs ok but i have a problem with the heating the heaters keep going on and off the heaters only stay on for about 10 seconds then go off for approx 1 minute could you please advise, also there is a small copper strip on the back of the dryer which is covering a small shaft which turns with the dryers movement what is this .