LG Electronics 553cc, 453cc instruction manual Maintenance, Cleaning, Inspection and Service

SECTION 4 MAINTENANCE

4.1 GENERAL

If this power source does not operate properly, stop work immediately and investigate the cause of the malfunction. Maintenance work must be per- formed by an experienced person, and electrical work by a trained electrician. Do not permit un- trained persons to inspect, clean, or repair this power source. Use only recommended replace- ment parts.

ELECTRIC SHOCK CAN KILL! "Machinery Lockout Procedures" should be employed. If it is not pos- sible to use padlocks, attach a red tag to the line disconnect switch (or fuse box) warning others that the circuit is being worked on. Placing the power switch in the off position does not remove all power from inside the power source.

4.2 CLEANING

Periodically, remove the cover from the power source and blow accumulated dust and dirt from the air pas- sages and interior components by using clean low pressure air. The frequency cleaning is required de- pends upon the environment in which the power source is used.

It is imperative that all air passages be kept as clean as possible in order to allow adequate air flow to provide proper cooling.

After cleaning with low pressure air, check for and tighten any loose hardware, including all electrical connections. Check for frayed and/or cracked insula- tion on all power cables and replace if necessary.

Failure to replace worn or damaged cables may result in a bare cable touching a grounded object. The resulting electrical arc may injure unprotected eyes and will present a serious fire hazard. Body contact with a bare cable, connector, or conductor may result in severe electrical shock, causing seri- ous burns or death.

4.3 INSPECTION AND SERVICE

Keep the power source dry, free of oil and grease, and protected at all times from damage by hot metal and sparks.

4.3.1 Fan Motor

Keep the fan motor free of accumulated dust and dirt.

4.3.2 Transformer

Other than periodically cleaning the dust and dirt from the transformer, no maintenance is required. Ensure that only clean, dry, low pressure air is used.

4.3.3 Control Circuits

These circuits are protected by two 10 amp circuit breakers mounted in the front panel. If these open, the contactor will not operate.

4.3.4 Over Temperature Protection

If the power source reaches an abnormally high internal temperature, the thermal protection will deenergize the contactor circuit, shutting down the power source but leaving the cooling fan on. After the power source has cooled to a safe level, the thermal protection will auto- matically reset. While deenerigized, the contactor can not be operated.

4.3.5 Digital Voltmeter/Ammeter Calibration

To verify the accuracy of the digital voltmeter/ammeter combination, the following procedure can be performed periodically:

1 . Place the Panel/Remote switch in Panel position.

2.Disconnect cables from the output terminals and then connect an accurate DC voltmeter to the output terminals.

3.Open the front control panel by removing the two mounting screws from the upper corners. Lo- cate the J9 jumper plug on the control pc board and remove the plug. The J9 jumper plug is located just left of the meter pc board ribbon cable connection plug J10.

4.Place the Contactor switch in the On position

5.With the primary input power on, turn the Current control knob until you get 25V on the DC voltme- ter. Compare the reading with the reading on the digital voltmeter on the front panel.

6.If there is a difference in the voltage readings, remove meter board from its four mounting posts, and adjust the trimpot (R13) on the meter board with a small screwdriver until the digital meter reading matches the DC voltmeter read- ing. When satisfied, reassemble meter board, reconnecting J9 jumper plug, and reassemble front control panel.

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