Operating instructions

25
COMPRESSORS
GENERAL INFORMATION
Hilomast compressors are air cooled, oil-less electric motors of the diaphragm type
enclosed in a steel case. All models incorporate a pressure controlled switched to
maintain the correct mast working pressure. They are quiet, maintenance free and
assembled from components that have a proven reliability over many years.
Approximate Rate of Mast Extension (Metres per Minute)
Compressor
Type
NH Series NK Series NL Series NX Series NY Series
NC1 7.2 4.2 2.6 1.7 -
NC2 13.5 8.1 4.8 3.2 1.7
NC3 - 18.1 10.8 7.5 3.9
To calculate time to fully extend mast: The height of mast is divided by rate e.g. for
NL12 mast with NC2 compressor – extension time = 12
) 4.8 = 2.5 minutes. The time
to reach maximum pressure is approximately 2 x extension time e.g. 5 minutes.
(1) Air pressures are monitored by a differential pressure switch, which will stop the
compressor at a pre-set level and restart the unit when pressure falls below a
second pre-set level. The pressures will normally be set at the factory and will be
shown on the label on the front of the case.
(2) Although electrical components are continuously rated; it is wise to check that the
compressor is switching off automatically. If not, the mast and compressor should
be checked for air leaks.
(3) Ensure that there is an adequate air space around the casting, as serious
overheating of the unit may result.
(4) Units may be fitted with a remote control. Since mast systems run on low air
pressure, it is advisable to keep pressure and exhaust hoses as short as
possible, as this will affect the extension and particularly retraction times
markedly. If the compressor forms part of a fixed installation and has to be sited
away from the mast, the exhaust valve may be removed and re-sited at the base
of the mast.
(5) Compressors should be placed on a level with or below the base of the mast to
prevent moisture build up in the airlines. If a compressor has to be placed higher
than the base of the mast, care must be taken not to allow water to become
trapped in the airlines. Disconnect the airline from the mast below out the line at
frequent intervals or fit a drain valve at the base level of the mast.