I am going to hook up some Peco PL 10's & PL 10W's (turnout switches) in my layout.(DCC) I am using Peco code 100 Insulfrogs. The power source for the switch motors is 16.5vac, 25va. Why do most of the motors buzz real loud? The turnouts are loose. It seems to be louder one way over the other. On some motors it works perfect, a good solid click. Thanks.