Advice for stopping and re-starting air compressors
If you need to reduce production and switch off your air compressors temporarily, we have put together some stopping and re-starting guidelines for you to follow.
How to stop air compressors for periods of time due to factory closure or shutdown
If the compressors are to be stopped for a prolonged period of time the following rules should be applied.
- VSD compressors: Carry out a programme stop, make sure the electrical power supply is left turned on to keep the capacitor bank charged and ready for restart.
- Water-cooled air compressors. After stopping be sure to isolate the water supply. This will stop condensate forming inside the compressor element(s). Don’t forget to turn it back on at start up. Please make sure any air blast cooling systems are turned off.
- Atlas Copco Z compressors – These need the main drive shaft to be manually rotated via the motor drive coupling, 3 complete rotations, once a week. This is to prevent the low pressure and high pressure compression stages from seizing up during a long period of down time. If the Z Compressor is a VSD version, don’t forget to turn the power supply back on after turning the compressor over by hand, to protect the inverter drive capacitors.
- Centrifugal / ZH compressors – should be programmed stopped, leave the power supply on. They need to have the auxiliary oil pump left turned on electrically whilst the compressor is shut down. This will maintain the oil temperature and periodically start up the auxiliary oil pump to circulate warm oil around the bearings during long periods of downtime.
Starting an air compressor up after long periods of shutdown
First turn off the power supply to the air compressor, remove the drive shaft protection guard and turn the drive coupling to check that the compressor is free to turn. If the compressor turns freely, re fit the guard and turn on the power supply to the compressor; turn on the cooling water and air blast cooling system if the compressor is water cooled. Close the compressor air discharge valve and start the compressor, then slowly open the air discharge valve until the air pressure equalises out between the compressor and the air net, then the compressor is back online. If the air compressor is connected to a sequence controller, make sure the compressors are integrated onto the controller/ optimiser.
If you require any further information, our contact details are: (01) 450 5978 / info.ireland@ie.atlascopco.com.