Maintenance of Industrial Control Equipment
ATTENTION:
Risk of injury or death exists.
Performing service on energized Industrial Control Equipment can be hazardous. Severe injury or death can result from electrical shock, bump, or unintended actuation of controlled equipment. Recommended practice is to disconnect and lockout control equipment from power sources, and release stored energy, if present. See National Fire Protection Association Standard No. NFPA 70E, Part II and (as applicable) OSHA rules for Control of Hazardous Energy Sources (lockout/tagout) and OSHA Electrical Safety Related Work Practices for safety-related work practices. These publications include procedural requirements for lockout/tagout, and appropriate work practices, personnel qualifications, and required training where it is not feasible to de-energize and lock out or tag out electric circuits and equipment before working on or near exposed circuit parts.
Periodic Inspection
Periodically inspect industrial control equipment. Base inspection intervals on the environmental and operating conditions and adjust the intervals as necessary. An initial inspection within 3 to 4 months after installation is suggested. See National Electrical Manufacturers Association NEMA) Standard No. ICS 1.3, Preventive Maintenance of Industrial Control and Systems Equipment, for general guidelines for defining a periodic maintenance program. Some specific guidelines for Rockwell Automation products are listed here.
Contamination
If inspection reveals that dust, dirt, moisture, or other contamination has reached the control equipment, the cause must be removed. Contamination can indicate an incorrectly selected or ineffective enclosure, unsealed enclosure openings (conduit or other), or incorrect operating procedures. Replace any improperly selected enclosure with one that is suitable for the environmental conditions. See the Industry Installation Guidelines for Pulse Width Modulated (PWM) AC Drives, publication DRIVES-AT003, for guidance on environmental considerations. See NEMA Standard No. 250, Enclosures for Electrical Equipment, or UL 50E Electrical Equipment Enclosures, for enclosure type descriptions and test criteria.
Replace any damaged or cracked elastomer seals and repair or replace any other damaged or malfunctioning parts (for example, hinges and fasteners). Dirty, wet, or contaminated control devices must be replaced. Compressed air is not recommended for cleaning because it can displace dirt, dust, or debris into other parts or equipment, or damage delicate parts.
PowerFlex®
755T products with XT use dielectric grease to protect critical connections from the effects of corrosive gases. When you disconnect or reconnect a greased connection, always inspect for dust, dirt, conductive debris, or other contaminants. If contamination is found, thoroughly clean receiving surfaces and reapply dielectric grease as described in the dielectric grease section.Blowers and Fans
Inspect blowers and fans that are used for forced air cooling. Replace any that have bent, chipped, or missing blades, or if the shaft does not turn freely. Apply power momentarily to check operation. If the unit does not operate, check and replace wiring, fuse, or blower or fan motor as appropriate. Clean or change air filters as recommended in the product manual. Also, clean the fins of heat exchangers so convection cooling is not impaired.
Operating Mechanisms
Check for proper function and freedom from sticking or binding. Replace any broken, deformed, or badly worn parts or assemblies according to individual product renewal-parts lists. Check for and retighten any loose fasteners. Lubricate if specified in individual product instructions. Note: Allen-Bradley® magnetic starters, contactors, and relays are designed to operate without lubrication. Do not lubricate these Allen-Bradley devices because oil or grease on the pole faces (mated surfaces) of the operating magnet can cause the device to stick in the “ON” mode. Some parts of other devices are factory lubricated – if lubrication during use or maintenance of these devices is needed, it is specified in their individual instructions. If in doubt, consult your nearest Rockwell Automation sales office for information.
Contacts
Check contacts for excessive wear and dirt accumulation. Wipe contacts with a soft cloth, if necessary, to remove dirt. Discoloration and slight pitting does not harm contacts. Do not file contacts - this action shortens the life of the contact. Do not use contact spray cleaners because residue on magnet pole faces or in operating mechanisms can cause sticking, and on contacts can interfere with electrical continuity. Replace contacts only after the silver has become badly worn. Always replace contacts in complete sets to avoid misalignment and uneven contact pressure.
Terminals
Loose connections in power circuits can cause overheating that can lead to equipment malfunction or failure. Loose connections in control circuits can cause control malfunctions. Loose bond or ground connections can increase the hazards of electrical shock and contribute to electromagnetic interference (EMI). Check the tightness of all terminals and bus bar connections and torque any loose connections properly. Infrared technology can be used to check for hot (high resistance/loose) connections during periodic maintenance. Replace any parts or wiring that is damaged by overheating, and any broken wires or bond straps.
Coils
If a coil is overheated (contains cracked, melted, or burned insulation), it must be replaced. In that event, check for and correct overvoltage or undervoltage conditions, which can cause coil failure. Be sure to clean any residues of melted coil insulation from other parts of the device or replace such parts.
Pilot Lights
Replace any burned-out lamps or damaged lenses.
Photoelectric Switches
The lenses of photoelectric switches require periodic cleaning with a soft dry cloth. Reflective devices that are used with photoelectric switches also require periodic cleaning. Do not use solvents or detergents on the lenses or reflectors. Replace any damaged lenses and reflectors
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