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| Vacuum pump for high voltage transformer potting |
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| joeqsmith:
--- Quote from: xzswq21 on August 11, 2021, 07:05:24 pm ---Do you know any small size and reliable vacuum pumps and vacuum chambers? --- End quote --- Sorry but I have no idea what country you are even in. |
| NiHaoMike:
--- Quote from: langwadt on August 11, 2021, 11:08:00 pm ---if you have plenty of water (or a water pump) a water aspirator? --- End quote --- The only thing venturi type vacuum pumps are good for is applications where they're likely to suck contaminants that would damage most pumps. It's not at all difficult to find a mechanical pump that can pull lower. |
| xzswq21:
What do you think about the Leybold TRIVAC series (but used not a new)? For example Trivac D 2.5 E? Thanks |
| geggi1:
Check on youtube. You will find several videos on how to make a vacuum chamber with a fridge compressor and a pressure cooker. Mos of the time these builds are used for potting and is probably sufficient for your use. |
| jonpaul:
Bonjour a tous: Just now reading the OP post by xzswq21 in 1980s and 1990 we made many potted HVPS with transformers for 12 KV aviation PSU. ~ 10,000 pcs were made over the years. 1/ The potting compound is critical esp for fill and cure chemistry as well as creation of internal mechanical stress during cure. 2/ Generally a two part heat cure epoxy/silica/filler is used. 3/ The device used is a vacuum oven, which are available from industrial equipment suppliers in all sizes. Check epay for used ones. 4/ Homebuilt vacuum is possible but somewhat risky from safety and yield. Consult a few vacuum technique textbooks, many are available. 5/ We pulled ~ 1mm Hg and kept the pumps running for the entire cure cycle, many hours or overnight. 6/ After cure, an annealing cycle is used to relieve internal stresses. 7/ Stress can crack the ferrite and damage insulation and other parts. Poor Yield kills profit and results in useless bricked units. We had 50% initially and 95% after a year of process and compund improvement. 8/ Stress is proportional to potting shell dimensions, our parts were ~ 1x1x3". Larger shells may have worse stress. I hope this info is useful to the OP and others. Just the ramblings of an old retired EE..... Bon Chance! Jon |
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