Loud hum noise coming from my Goodman?

There is a loud hum noise coming from my Goodman heating and air conditioning unit. The fan doesn't come on and after about 15-20 min the breaker trips and I have to go back out to restart it. What can I do because this will be the 3rd time I have to call someone to come out and fix my heating unit. The first time was the a/c being frozen over. The second time was a circuit board getting too much moisture on it and shorted out. Now it's the outdoor unit. I'm tired of having to deal with this!