General

  • Have the correct tools and know how (training).
  • How long has the rectifier been out of service?
  • Was the rectifier in storage, covered, locked out, serviced or moved?
  • Make a checklist as you go and document observations.
  • Make sure you inspect all rectifiers. Check for out of the way locations.
  • Keep a list of all rectifiers and their present status.
  • Check variables for specialized equipment.
  • Repair and record findings.
  • Look for items in close proximity. Keep 36” clearance around rectifiers. Check for trip hazards in the area.
  • Communicate the startup to affected people in the area, including other shifts.
  • Review the maintenance logs.
  • Has work been done on the rectifier during the shutdown? Has the service been completed? Is there still work to address prior to startup?
  • Look for signs of repair/maintenance you did not know about.
  • Consult user manual for specific startup process.
  • Review SOP (Standard Operating Procedure) for startup sequencing. Startup line operations in correct order.
  • Address any issues seen, review troubleshooting charts.
  • Post start up. Log all maintenance items addressed.
  • Review spare parts inventory.
  • Review and re-set PM schedule.
  • Monitor rectifiers during initial production.
  • Use proper PPE.
  • Contact APP for assistance if needed.

Controls

  • Inspect controls, verify that gauges and potentiometers are not damaged.
  • Look over all control wiring terminations for loose or frayed wring.
  • Verify communication with automation system.
  • Test controls, use a dummy load if possible prior to running product.
  • Be sure voltage and current control is achieved.
  • For advanced checks you can use an oscilloscope to verify proper output wave shape.

Electrical

  • Document training related to the rectifiers, IE, LOTO and electrical safety.
  • Before powering up, check input cabling and power distribution for correct torque. 
  • Heating and cooling can cause loose connections.
  • Check incoming line voltage and current. Each input phase should be equal.
  • Make sure all enclosure panels are in place and closed.
  • Be sure proper procedures have been followed. IE: Lockout removal.
  • Proceed with energizing the equipment in standby mode (Not producing output yet).
  • Make sure there are no fault indications or other areas of concern.
  • Check that the DC buss connections are tight.
  • Check that there is nothing leaning on or shorting the output buss bars.
  • Use thermal imaging to verify expected temperature and possibly locate items of concern that may not been seen unless under load. 

Cooling

  • For air cooled units, check that air is readily available. For forced air ventilation, check for obstructions.
  • If equipped, check that air filters are clean and in place.
  • For water cooled units, confirm chiller settings.
  • Pre-start pumps, open bypass / recirculation valves.
  • Check for leaks. Was rectifier stored in freezing temps?
  • Circulate water through rectifier to be sure all cooling lines are flowing freely.
  • Re-check that cooling media is running and effective.