# VFD Danfoss VLT 6000 HVAC



## aeroscott (Jan 5, 2008)

Just found this at the junk yard . 50 hp , 380 -460 vac ( 850 dcv max), variable torque only ,censer or censer less , 110% overload max . Can handle DC bus with fan and resister mods . Thinking of it for small ev or running pumps/other loads on a barge . I'm planning on high voltage battery .


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## steven4601 (Nov 11, 2010)

.50 or 50hp?
.50 may not be useable at all. that is 350watt's
50hp, or 35kw. Using at full potential may ruin your conduits if used for pumping


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## aeroscott (Jan 5, 2008)

That's 35kw , big pumps 10 to 20 hp, air compressor 10 hp , winches 10-20 hp, . I have inverter welder I'm running off 5kw (240v 1 phase) ups inverter it runs OK but weak . Could I run on the vfd as a inverter power supply at 60hz fixed output . The welder runs on anything 1 or 3 phase, just way better on 3 phase .


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## steven4601 (Nov 11, 2010)

It is not an ups or an DC to AC converter.


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## aeroscott (Jan 5, 2008)

is it the inductor (motor) missing part that keeps the vfd from becoming ups or stand alone inverter . If so, could a inductor (non motor) be added to accomplish this . It may be simpler to find a 3 phase ups , I've only seen a few .


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## steven4601 (Nov 11, 2010)

The reason why its likely not to work is the low switching frequency.

Motor drives switch at low frequencies compared to what an UPS does. Filtering out 3 to 5kHz for 50hz line frequency isn't really ideal. to create 50Hz at power levels you'd be much better of nearing 20 to 30kHz to keep the steps & ripples small. 

Also another problem is the fact that just adding a filter doesn't help. You'll need some sort of voltage feedback to get a constant sinusodial voltage across a wide load variation. Without feedback you'll probably have a square wave at no load, and a sine at elevated resistive loads. Non liniear loads (dumb rectified outputs) will cause massive distortion once again. 

Yes it will work, but it will be a messy, noisy, EMC troubled solution.


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## aeroscott (Jan 5, 2008)

Thanks for your great help in understanding this situation .PS this morning I have been bound over for criminal contempt of court for navigating in a federal waterway in the city of West Sacramento with out a city of West Sacramento permit , one little detail I'm not in the city of west Sacramento . I am in the city boundaries but not in the city , can't get a straight answer why but for over 20 years I've been told by the city I'm not in the city . I told this to the judge and he got this huge smile , no other response . Details can't stop this bs .

So back on point , it could be done with a (filter) inductance with voltage feedback . would the inductor need be a variable one considering a variable load ? And to the welder load , I would think it would depend on the filtering in old pow con inverter welder (being that it converts to dc with filtering and a inducter) or just run a transformer welder with huge iron core with voltage feedback ? I apologize for the meany questions . thanks again .


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