WILLIAMS CONTROLS WM81 SERIES 'N/' PRODUCT DESCRIPTION DESCRIPTION The WM 81 series consists of non-grounded switches that respond to a drop of air pressure below a preset level. The WM 81 switches feature an adjustment that allows the actuation setting to be modified. The switches are shipped from the factory with this setting preadjusted to 50-60 PSI (344,7-413,7 kPa). When the pressure drops below the preset value, these switches activate a light or buzzer to indicate that a low pressure condition exists. OPERATION When the control pressure exceeds the preset level, a diaphragm in the switch holds the contacts in the open position. If the pressure decreases below this level, the diaphragm is spring-returned and the contacts close. A customer-supplied light or buzzer warns the operator of the low pressure condition. APPLICATION The WM 81 series single-pole, single-throw switches are commonly installed as signal devices in pneumatic braking systems. Designed for low voltage (6-24 VDC), low amperage applications, these switches are frequently used to activate a warning light or buzzer when a low pressure condition exists in the vehicle's air brake system. The WM 81 series is not UL approved. TYPICAL INSTALLATION ADJUSTABLE PRESSURE SWITCH FUNCTIONAL DIAGRAM w CONTROL PRESSURE BELOW PREADJUSTED SETTING CONTROL PRESSURE ABOVE PREADJUSTED SETTING WILLIAMS CONTROLS, INC. 14100 SW 72ND AVENUE, PORTLAND, OREGON 97224, TEL: (503) 684-8600, TELECOPIER: (503) 684-8610

DESCRIPTION BODY COVER DIAPHRAGM ASSEMBLY WASHER SPRING SCREW SPRING SEAT SCREW NUT NUT SCREW SLEEVE INSULATOR *For continuous operation beyond this range, contact factory. This component is classified as a nonrepayable item. TOORDER, SPECIFY WM81 Model Number PART NUMBER 111237