Abstract: A roof-mounted electrostatic air cleaner for connection to an exhaust duct has a sectionalized cabinet with detachably connected, directable inlet and outlet sections and an intermediate precipitator section, a traveling manifold with multiple spray nozzles is arranged to wash the outer surfaces of precipitator cell end plates as well as both surfaces of intermediate collector plates, and a construction and arrangement of large capacity precipitator cells provides for their convenient and safe assembly and removal from the cabinet.

Abstract: A safety device for preventing the automatic restart of a motor upon restoration of power to the motor. This device, in its preferred embodiment, includes a thyristor switch, such as a triac, in one of the power leads to the motor which is triggered by energizaton of the motor. Upon deenergizaton of the motor, the thyristor switch switches to its non-conductive state thereby preventing automatic restarting of the motor upon restoration of the power. A selectively actuable, momentary run switch is provided to momentarily shunt out the thyristor switch so as to selectively permit the restart of the motor.