Instrumentation Monthly Test | Measurement | Control
The enclosures that protect them must have strictly controlled internal environments with interior temperatures that are carefully maintained within a few degrees. If not, the impact can be harmful to the inverter drives, power supplies, contactors, PLCs and other electrical and electronic components operating within them. This requires careful control of the climate within the enclosure.
Here, Jason Swann, Rittal Product Manager for Climate offers some practical tips on how to evaluate an existing enclosure climate control through a series of simple checks.
Like all electrical equipment, drives create heat and they therefore have a major influence on the temperatures inside enclosures. Drives are often quoted as having efficiency of 97 per cent, so one with a rated output of 150kW can produce as much as 4.5kW of heat.
As well as the heat loss inside the enclosure, ambient temperatures within a production facility will also have an impact on the temperatures that a drive is operating within. A typical enclosure climate control system is designed for an internal enclosure temperature of 35°C. This means that the performance of a cooling unit should be specified so that the average internal enclosure temperature of 35°C can be guaranteed under all load conditions and under all the ambient conditions that could be met at the machine’s location.
Checking the enclosure temperature
The first check is to measure the temperature within the enclosure to assess its climate control capability. Temperature sensors should be placed in a position within the airflow of the enclosure, sensors should not be placed on or near direct airflow from high temperature components. Otherwise temperature readings can be found to be inaccurate. The sensors should be left to monitor the temperature trend over a period of time.
If the sensor records air temperatures of well over 35°C (set point) then the output of the cooling unit should either be considered insufficient or, alternatively, that there has been a malfunction of the cold air routing in the enclosure. This means that the cooling air cannot reach (or can only partially reach) the temperature-sensitive components