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Humidity Control Actuators

Humidity Control Actuators

Humidity Control Actuators

Hi All,

I'm looking to do some testing of power conversion equipment at elevated relative humidity in the near future. Compared to many applications, these systems have higher power dissipation and sizes which are potentially too large for typical environmental chambers. I'm interested in the possibility of making our own temperature/humidity controlled enclosure for flexibility and considering the power handling requirements in particular.

Can anyone recommend an off-the-shelf humidity actuator that would be appropriate and capable of operation at elevated temperatures (max temp between 40-85 °C depending on negotiated test values and practical limits)? I have seen ultrasonic, bubble, boiling, and wick/fan based approaches but haven't seen anything marketed for industrial/scientific applications. Near term expectation is for ~30-50 cubic feet (possibly up to ~1000 cubic feet) and to use heaters/air-air exchangers to regulate temperature in a closed system. Probably I'm looking in the wrong places for actuators...

Any other practical advice/lessons learned would be greatly appreciated!

RE: Humidity Control Actuators

I have used environmental test chambers large enough to pull a car into, chances are there is a local test house that has one big enough for your application.

Where are you located?

If there is a local shop, are you open to renting the use of a chamber at a rate of ~$300/day for your low end of 30 cubic feet? Sorry but I don't remember what the large one cost, it was a long time ago.

RE: Humidity Control Actuators

Voltage and power levels are high enough that it's awkward to do elsewhere (1500VDC, >50 kW processed, ~1kW dissipated by UUT and at least one of the specified tests will be for an energized/operational unit requiring setup/support on-site).

That's certainly a reasonable rental rate. I'm partly comparing to HALT/MEOST chamber rentals at ~8x your indicated rate. I'm in southern CA, so a good selection of local test sites if we outsource.

RE: Humidity Control Actuators

The test lab would likely have 440 VAC available, you would need to bring the equipment to go from there but I don't think the thermal load would be an issue, though it may drive you to a bigger chamber than you might need space-wise. I would suggest trying to rent if you can, save yourself a lot of headache when you can't reach one corner case or another with a home made chamber and need to start over.

HALT chambers have the shock and vibe stuff integrated so they would be more expensive. I am surprised at 8X though.

Element and NTS are the local ones we use around here. Looks like both have locations in the LA area.

RE: Humidity Control Actuators

Rather than specifying a chamber, I would suggest you specify the specific test conditions and let the test house figure what they can do; you otherwise run the risk of overconstraining the test house

TTFN (ta ta for now)
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