First I have an inground 18 x 36 pool. The 1 HP Hayward pump is brand new with a Century 2 speed 1081 pool & Spa Duty motor. After installing, when I hit the switch it just hummed. Checked the impeller which turns freely. Took pump back out to check some things and this is what I found. The motor shaft turns with no power, but seems to freeze when I bumped a little power to it. Any idea what the problem might be?