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Technical Information

Degree of protection acc. to IEC 60947-1

Protection ratings are prefixed by the internationally agreed letters IPfollowed by two digits.1 2
nd Short descriptionDefinitiondigit
st digit:Pertains to solid objects2 1Protected againstDripping water (vertically falling drops)dripping watershall have no harmful effect.
nd digit:Pertains to water.1 2Protected againstVertically dripping water shall have nodripping waterharmful effect when the enclosure is tilted when tiltedat any angle up to 15° from its normal up to 15°position.
st Short descriptionDefinitiondigit 1Protected againstExcludes solid objects exceeding 50 mmsolid objectsin diameter and protects against contact greater than 50 mmwith live and moving parts by a large bodysurface such as a hand (but not against deliberate access). 3Protected againstWater falling as a spray at an angle upspraying waterto 60° from the vertical shall have noharmful effect. 4Protected againstWater splashed against the enclosuresplashing waterfrom any direction shall have no harmfuleffect. 2LProtected againstExcludes solid objects exceedingsolid objects12,5 mm in diameter and protects against greater thancontact with live and moving parts by a 12,5 mm andstandard test finger or similar objects against contact bynot exceeding 80 mm in length. standard test finger 5Protected againstWater protected by a nozzle against thewater jetsenclosure from any direction shall haveno harmful effect. 3Protected againstExcludes solid objects exceeding 2,5 mmsolid objectsin diameter or thickness. greater than 2,5mm 6Protected againstWater from heavy seas or waterheavy seasprojected in powerful jets shall notenter the enclosure in harmful quanties. 4Protected againstExcludes solid objects exceeding 1 mmsolid objectsin diameter or thickness. greater than 1 mm 7Protected againstIngress of water in a harmful quantitythe effects ofshall not be possible when the immersionenclosure is immersed in water understandard conditions of pressure and time. 5Dust protectedPrevents ingress of dust in quantitiesand locations that would interfere with the intended operation of the equipment. 8Protected againstNo ingress of water.submersion 6Dust tightPrevents ingress of dust.

Terminal markings acc. to EN50011 Resistance to climatic conditions acc. to IEC60068

Auxiliary contacts of AC contactors and contacts of contactor relays and thermal overload relays are particularly marked. The terminal markings of normally-open contacts are printed as positive figures, they of normally- closed contacts as negative figures. This gives a clear indication of the function of the contacts. The figure below illustrates the determination of terminal markings for contactors with auxiliary contact blocks.Sequence number Function numberThe complete terminal marking according to EN50011 and EN 50012 results from the sequence numbers on the contactor relay or ac contactor (2., 3.) and the function numbers on the auxiliary contact blocks (e. g. .1, .2, or .3, .4). Open-type devices are climate-resistant in the constant climate according to IEC60068-2-3 (this is a climate with an ambient temperature of 40°C and an atmospheric humidity of 90 to 95%). Enclosed devices are climate-resistant in an alternating climate according to IEC 68-2-30 (this is a moist alternating climate with a 24-hour cycle between climates with an ambient temperature of 25°C, and an atmospheric humidity of 95 to 100% and an ambient temperature of 40°C, and an atmospheric humidity of 90 to 96% in the presence of condensation during rises in temperature). Data are valid up to an altitude of 2000m above sea level.

Short circuit protection

Back up fuses should be used to protect contactors and starters againstshort circuits. For starters the device with the smaller admissible fuse atthe main and at the control circuit (contactor or thermal overload) determinesthe fuse size. After a short circuit devices have to be checked for correct operation. Disconnect power before proceeding with any work on the equipment! D677E 5