reading electrical schematics??

i have a electrical schematic at my work with three different symbols, in three different octagons C,E and a D inside octagon's...and also a diamond with an F in it. Are these general electrical schematic symbols...??? if so what do they represent? its on a 120 volt convayer motor, going to a Hands off automatic switch thru two emergency stop switches. The motor wont come on, and there is power going out #1 to the thermal overloads in the motor, but only 40 votls at the hand switch where there should be 120 v's and all the emergency stops are good and the thermal overloads in the motor are good as well. help???

Thanks
Ben

i have no way to scan it, but I can make a copy of this particular part and scan it when I get home tomorrow....(heading up to the country for the rest of the weekend).
thanks
Ben