panasonic 01 safetyprecutions free download

File name 01_safetyprecutions.pdf

Safety Precautions General Guide Lines 1. When servicing, observe the original lead dress. If a short circuit is found, replace all parts which have been overheated or damaged by the short circuit. 2. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly installed. 3. After servicing, make the following touch current checks to prevent the customer from being exposed to shock hazards. 4. Always ensure cover label TBM4GU113 is correctly replaced before returning to customer (see Fig.1). Fig. 1 Touch-Current Check 1. Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check. 2. Connect a measuring network for touch currents between each exposed metallic part on the set and a good earth ground such as a water pipe, as shown in Fig. 2. 3. Use Leakage Current Tester (Simpson 228 or equivalent) to measure the potential across the measuring network. 4. Check each exposed metallic part, and measure the voltage at each point. 5. Reserve the AC plug in the AC outlet and repeat each of the above measure. 6. The potential at any point (TOUCH CURRENT) expressed as voltage U1 and U2, does not exceed the following values: For a. c.: U1 = 35 V (peak) and U2 = 0.35 V (peak); For d. c.: U1 = 1.0 V, Note: The limit value of U2 = 0.35 V (peak) for a. c. and U1 = 1.0 V for d. c. correspond to the values 0.7 mA (peak) a. c. and 2.0 mA d. c. The limit value U1 = 35 V (peak) for a. c. correspond to the value 70 mA (peak) a. c. for frequencies greater than 100 kHz. 7. In case a measurement is out of the limits specified, there is a possibility of a shock hazard, and the equipment should be repaired and rechecked before it is returned to the customer. Measuring network for TOUCH CURRENTS COLD WATER PIPE (EARTH GROUND) RS=1500 CS=0.22F 10k TO APPLIANCES EXPOSED R0=500 U1 (V) 0.022F V U2 (V) METAL PARTS Resistance values in ohms () V: Voltmeter or oscilloscope Input resistance: 1M (r.m.s. or peak reading) Input capacitance:200pF Frequency range: 15Hz to 1MHz and d.c.respectively NOTE