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Renewable Energy Q&A / Re: Max winding temp
« Last post by lighthunter on June 14, 2022, 06:26:59 pm »Update:
Thanks again Pete for all the ideas and thoughts on this one. All attempts to adjust the volt/amp curve via vfd programming failed as the OEM disallows it. Weve yet to get any real support from those people.
The compressor has been running fine for a while now. I drilled a hole near the bottom of the end frame and put compressed air to it so it blows cool air through the cage out the cover of electrical box. A co-worker drilled the fitting a bit larger as the cooling requirement was higher than i had anticipated. It takes around a 6hp efficiency hit just to cool it but it works. Runs about 175F now. Whats difficult for me is knowing exactly whats ok? A different unit had oiltemp that reached 221F today. Pressure washed cotton fuzz from radiator and now at 196 where thermostat regulates it. Maybe its fine for winding temp to be 250F no one i know will go there and articles written about it tiptoe around the subject. Oddly most manufacturers do not put temp sensors in windings yet a common house fan includes this as a safety device. A thermal cutoff or tco. As i write this im reminded of an event years ago... 1998... how time has gone... when a laser roots blower also siemens motor, failed due to a temp sensor in winding. I jumpered and machine ran, i ordered a temp switch in a T0220 package and inserted/epoxyed into winding at end of motor seems like i started at 110C and kept having to order higher ones till i got one that didnt trip under normal circumstances. Seems like the number was 115 or 120C when i finished and that one ran for years that way. So by that info i can set this at 250F and reduce the orfice size to maybe 4HP of cooling. Of course an air booster in reverse trading pressure to volume would reduce the flow requirement again. Anyone else agree i can increase thermal trip point to 250F or 120C?
I kinda feel stupid i forgot the eqperience i learned back then about winding temp.
Perhaps i better ask the elder gentleman what class wind wire he used for this one.
Its not an ideal solution but it is a solution and it does run welll now. Anyone have an idea on a moisture sensor for air line. I will need it to fault on humidity as moisture will kill windings too. So far our dryer is flawless but theres no feedback to stop anything if it doesnt remove all moisture.
Hope everyone is doing well, i havent had much time to post as garden, work and other odd jobs have been over the top lately.
Thanks again Pete for all the ideas and thoughts on this one. All attempts to adjust the volt/amp curve via vfd programming failed as the OEM disallows it. Weve yet to get any real support from those people.
The compressor has been running fine for a while now. I drilled a hole near the bottom of the end frame and put compressed air to it so it blows cool air through the cage out the cover of electrical box. A co-worker drilled the fitting a bit larger as the cooling requirement was higher than i had anticipated. It takes around a 6hp efficiency hit just to cool it but it works. Runs about 175F now. Whats difficult for me is knowing exactly whats ok? A different unit had oiltemp that reached 221F today. Pressure washed cotton fuzz from radiator and now at 196 where thermostat regulates it. Maybe its fine for winding temp to be 250F no one i know will go there and articles written about it tiptoe around the subject. Oddly most manufacturers do not put temp sensors in windings yet a common house fan includes this as a safety device. A thermal cutoff or tco. As i write this im reminded of an event years ago... 1998... how time has gone... when a laser roots blower also siemens motor, failed due to a temp sensor in winding. I jumpered and machine ran, i ordered a temp switch in a T0220 package and inserted/epoxyed into winding at end of motor seems like i started at 110C and kept having to order higher ones till i got one that didnt trip under normal circumstances. Seems like the number was 115 or 120C when i finished and that one ran for years that way. So by that info i can set this at 250F and reduce the orfice size to maybe 4HP of cooling. Of course an air booster in reverse trading pressure to volume would reduce the flow requirement again. Anyone else agree i can increase thermal trip point to 250F or 120C?
I kinda feel stupid i forgot the eqperience i learned back then about winding temp.
Perhaps i better ask the elder gentleman what class wind wire he used for this one.
Its not an ideal solution but it is a solution and it does run welll now. Anyone have an idea on a moisture sensor for air line. I will need it to fault on humidity as moisture will kill windings too. So far our dryer is flawless but theres no feedback to stop anything if it doesnt remove all moisture.
Hope everyone is doing well, i havent had much time to post as garden, work and other odd jobs have been over the top lately.