You may need scuba gear to get at them, but your drives and controls may still be usable with the right restoration procedures.

More than 100 rivers have flooded this summer throughout the Midwest and Mississippi Valley leaving an untold number of manufacturers facing the same question: Can watersoaked motor controllers and adjustablespeed drives be used once the water recedes? These same questions are asked after any flood — small and large — invades an industrial or commercial facility. In many cases, the answer is yes, if the right steps are followed by qualified service or maintenance personnel.

First of all, a few don’ts:
• Don’t even think of energizing any electrical equipment that has been under water before reconditioning it. Reason: It may look OK, but electrical parts exposed to flood waters can become grounded and pose an electric shock hazard or overheat and cause a fire.
• Don’t take short cuts while reconditioning the equipment.
• Don’t rush, take your time.
• Don’t gamble. If any aspect is unknown, contact the device manufacturer.

Water-soaked motor controls

Here are the steps for restoring motor starters, contactors, overload relays, control transformers, and related devices.

1. Cleaning. All equipment should be hosed down and scrubbed with a stiff brush. Water pressure should be limited to 25 psi maximum on insulation parts. Water temperature should not exceed or 194 F (90 C). An approved electromagnetic component solvent, such as Contact Re-Nu from Miller-Stephenson or Electro Contact Cleaner from LPS, should be used for a final cleaning of insulating surfaces, contact tips and magnet pole faces. Steam cleaning should not be used except on cabinets and enclosures from which the interiors have been removed.

2. Drying. Drying in the sun or in a warm dry room will take about 2 to 4 days. If heat is used for drying, it should be limited to about 212 F, preferable starting at about 150 F or lower and gradually building to 212 F. Plaster drying equipment, electric heaters, or baking ovens may be used. Approximately 24 hr drying by this method generally should be sufficient. For equipment operating at or above 250 V, greater caution in drying and cleaning should be taken, because of the greater susceptibility to insulation breakdown.

3. Lubrication. All mechanical joints, sliders, bearings, and moving parts should be cleaned and lubricated with any good lubricating oil. Exception: No oil should be applied to contact surfaces or magnet pole faces.

4. Coils and transformers. Wash with clean, hot water and dry by any of methods listed above. Magnet armature should be in open position or coil should be removed from magnet. For drying direct current (dc) coils by this method, a resistor in parallel with the coil is recommended to provide a discharge path for the kick voltage induced when the circuit is opened. Special care should be taken to dry out L.C. coils because, in operation, the inductive voltage may be several times normal voltage. Check with the megger for insulation resistance (one megohm).

5. Magnets. Wash, clean, and dry with cloth or air hose. Lubricate bearings, pins, and so forth. Clean magnet pole faces with any approved electromagnetic component cleaner (as mentioned earlier) to remove all oil film and surface dirt which might cause the armature to stick.

6. Contact surface. Clean tips with an approved cleaners such as mentioned earlier. Filing the tips is not recommended, but may be used if the surface is very difficult to clean. Do not use sandpaper or emerycloth which would deposit grit on the tips. Particular care should be taken with small contacts such as electrical interlocks, overload relays, and push buttons.

7. Insulating parts. All surfaces of contact blocks and chamber covers, yoke bars, overload relay blocks, and so forth, should be cleaned with any approved cleaner, particularly between poles and dried carefully. Surface drying is generally sufficient for glazed porcelain, Melamine, and nonabsorbent plastics. Unglazed porcelain, Bakelite, and Rostone absorb water and should be baked to dry thoroughly. (Rostone is the cold-molded material used in the vertical bus insulators.) Using megger, check from pole-to-pole and from each pole-to-ground, for one megohm minimum insulation resistance.

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