Need help wiring a motor control relay
I'm building an operational torpedo for my 60 inch Vosper Motor Torpedo Boat, MTB. I need a simple wiring diagram to do the following. Using a magnetic reed switch, I want the reed switch to apply 8.4v power through a relay to a Graupner Speed 480 motor. Problem is that much current destroys the little reed switch. One fried so far. So I bought a Radio Shack SPDT relay rated at 12V and 10A. The wiring diagram for the SPDT doesn't show how I get power to the coil that does not fry the reed switch in line to energize it. What am i missing here. The same 8.4V is used to power the relay coil and the motor, so shouldn't they both see the same amps? And won't that same load damage the reed switch used to energize the relay coil??? It would be simple if I could find a reed switch able to take the amps of the motor directly. Any electronics experts out there to help?
Items in this setup: 8.4vdc NiMH 800mAh battery - magnetic reed switch - SPDT relay - Graupner Speed 480 electric motor - Safety ON/OFF toggle switch to allow de-energizing system with battery plugged in. Safety switch allows me to connect battery to system and keep motor OFF until last minute. Just before closing up torpedo, I put magnet next to torpedo (reed switch just inside torpedo) to keep motor off while loading, then throw the safety toggle switch (ON). Torpedo halves are joined and system is armed to run the instant the magnet is moved away from the reed switch. Making any sense?
BTW, the motor runs at full power when the reed switch is thrown (normally on). This probably has a very simple solution, I hope...
Mike in Honolulu