The standard IEC / EN60947-4-1, referred to the contactor, of the contactors, prescribes that the operation of the contactors have to be within the temperature range of -5… + 40 ° C. In this temperature range the devices must guarantee correct operation with their maximum rated load. It is quite common for contactors to work over these temperature limits; this in consequence of the installation in extreme geographical environments or due to particular working conditions of the machine on which they are mounted. Lovato contactors can operate in the presence of higher or lower temperature in confront to the ones prescribed in the standard, in some cases a de-rating is necessary. Here below are some general indications about the behaviour of contactors in extreme temperatures ambient; we recommend that you contact our technical support for any clarifications for specific uses. Generally speaking, low temperatures do not cause electrical problems. The only case to take in consideration is the embrittlement of plastic materials; so shocks or wiring operations must be avoided when the equipment is in a very low temperature condition. Low temperatures do not cause deterioration of plastics or other components. Attention should only be paid to the use of electronically controlled
contactors in which some components may deteriorate if exposed to a lower temperature than the one indicated in the catalogue. High ambient temperatures are notoriously a problem because they are added to the normal heating generated by the contactor operation. Long periods of exposure to very high temperatures can lead to the permanent loss of mechanical properties due to thermal aging of the plastics. High temperatures influence the coil which can have an increase in the
resistance value, caused by the intrinsic property of the copper, which reduces the working performances. The terminals have a temperature increase due to the
passage of the current which, added to the ambient temperature, in extreme cases can lead to permanent deterioration of the properties of the plastics. In
general, in the presence of extremely high temperatures, these countermeasures can be considered: panel ventilation, contactor spacing to
avoid mutual heating and to facilitate heat dissipation and oversizing the contactors.
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