IEC 60068-2-53:2010 pdf – Environmental testing- Part 2-53:Tests and guidance – Combined climatic (temperature/humidity)and dynamic (vibrationlshock) tests.
If slow temperature change test or damp heat cyclic test is performed, the required exposure time starts with the beginning of temperature change.
If the specimen is mounted on shock absorbers, time shall be given for temperature stabilization of the absorber elements.
3.3 DynamIc test Information
The relevant specification shall contain dynamic test information, The dynamic test information includes following details (see also Clause 5):
a) Identification of dynamic test ( such as sinusoidal, random, mixed mode vibration or
b) seventies of dynamic stress;
C) axis and directions of dynamic stress;
d) duration and timing of dynamic stress (see Annex A);
e) IEC 60068-2-47 shall be referred to concerning mounting of specimen;
t) other details specified in the reference standards.
3.4 InItial measurement and functIonal performance test
The specimen shall be submitted to the visual, dimensional, functional and any other checks prescribed by the relevant specification.
3.5 Operating condition of speclm.n
In the case of electrically-operated specimens, the times at which the power supply shall be powered on or off and the voltage of the power supply within each temperature cycle shall be specified in the relevant specification.
The times at which other functions such as cooling, heating and various loads are switched on or off shall be stipulated in the relevant specification or controlled by a special type of test equipment.
3.6 Mechanical conditioning of specimen
The mechanical conditioning of the specimen per cycle shall preferably be performed in the last hour of the hot or cold phase, i.e. prior to the changeover to the following limit temperature. or shall be performed in any other combination which can be defined in the relevant specification. If the specimen is operated by power supply, this shall be connected for the duration of the mechanical conditioning.
4 Final measurements
The specimen shall be submitted to the visual, dimensional and functional checks prescribed by the relevant specification.
The relevant specification shall provide the criteria upon which the acceptance or rejection of the specimen is to be based.
5 Information to be given in the relevant specification
The relevant specification shall contain the following details as far as they are applicable
a) exposure time to temperature;
b) test chamber temperature change rate;
8.1 General
This annex furnishes fundamental comments for applying combined tests of temperature and/or humidity with vibration or shock, based on different parts within the IEC 60068 series,
For the purposes of combined testing, IEC 60068-1. Environmental testing — Part 1 General and guidance, shall be used together with the relevant preferred values described in
IEC 60068-2.
B.2 Consideration of test procedure
For combined testing, It may be necessary to test with high air circulation for the following reasons:
a) dissipation of heat from the shaker;
b) air circulation about the specimen may be reduced by the presence of the shaker.
8.3 Environmental conditions
In the following, the effects of low and high temperature and vibration on materials are described
a) Both low and high temperature can change the qualities of materials. In addition, the risk of damage Is increased by vibration. Equipment with many different materials or with ropy. elastic materials, can be very sensitive during a combined test of temperature, humidity and vibration.
b) Under extreme temperatures the characteristic frequency may be shifted so that the introduced vibration will be enhanced. At low temperature the effect is significant for a vibration absorber consisting of rubber elastic materials.
B.4 Testing equipment
The combined tests with temperature, humidity and vibration can be performed with different equipment, Typical is an electro-dynamic shaker with a climatic test chamber on top (see Figure B.1) or an electrodynamic shaker inside a climatic test chamber.
If an electro-dynamic shaker with a climatic test chamber above is used, the table of the shaker shall be thermally isolated from the body of the shaker and the climatic test chamber. Parts of the thermal isolation are not allowed to assign impermissible vibration. Mechanical coupling between the shaker and the test chamber shall be prohibited because the test chamber could be damaged.
8.5 Measurement of environmental conditions
B.5,1 Measurement of temperature
The equipment to measure the temperature can be stressed by high values of acceleration. Therefore, the temperature sensor shall be durably fixed. Also it shall not change the dynamic behaviour of the specimen.