AVO avo8-instruction-plates free download

File name avo8-instruction-plates.pdf

UNIVERSAL AVOMETER WORKING INSTRUCTIONS MODEL 8. IMPORTANT GENERAL To ensure accurate readings, the meter should be used face upwards. If necessary, set the pointer to instrument zero by means of the screw on the face of the panel. The lower pair of terminals should be used for all ranges on the switch knobs, the left-hand terminal being common for the 2500V. range also. When in doubt, always use the highest range and work downwards, there being no necessity to disconnect the supply. Never switch off current or voltage by rotating either switch to a blank position. The polarity shown at the terminals is correct for normal use, but a movement reversing switch marked "REV. M.C." is provided to facilitate certain tests. The automatic overload cut-out, if tripped, interrupts the main circuit and except in cases of abnormal overload, it provides complete immunity from damage. If it operates, disconnect the leads from supply, reset the cut-out with the meter horizontal, and clear the fault before reconnecting the leads. Since mechanical shock may cause it to trip, handle the meter carefully. If the meter is used on circuits in excess of 2500 V., it should be kept at the earthy end of the circuit or alternative precautions taken. The instrument itself has been tested at 6000 V., A.C., but special care should always be taken when testing high voltage circuits. Ensure that the leads are maintained in good condition. The resistance of the leads is approximately 0.02 ohms per pair. A copper oxide rectifier is incorporated for A.C. measurements, the calibration being correct for a sinusoidal input or for one of equivalent form factor (1.11). The decibel scale may be used with any A.C. current or voltage range. When comparing readings on different ranges, add 8 dB to pointer indication for each increase of 2