Overheat circuit for a utility vehicle

摘要

An overheat protection circuit includes a resistor having a first lead connected to the engine temperature switch and the power take off (PTO) relay coil circuit. The second lead of the resistor is connected to the output of an interlock circuit to provide an energizing voltage signal to the PTO relay for operation of the PTO driven attachment when preselected operating conditions are present on the vehicle. If for any reason the engine temperature rises above a preselected maximum operating temperature, the engine temperature switch will close and cause the voltage at the second lead to drop below the minimum operating voltage of the PTO relay. The PTO relay deenergizes to remove drive from the attachment. The PTO cannot be reengaged until the engine operating temperature drops below the maximum operating temperature. The resistor preferably is a positive temperature coefficient thermistor to reduce power dissipation through the circuit while the temperature switch is closed and the PTO relay is deenergized.