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Thread: 40hp Phase Converter or VFD?

  1. #1

    40hp Phase Converter or VFD?

    I have a brand new VFD that's "rated" for 5hp. This is a Huywang (amazon) VFD with the terrible instructions. I haven't wired it yet but have bookmarked enough threads and youtubes that if I do, it should work. There seems to be a crap shoot with these VFDs. I need it to power a 5hp 3phase powermatic planer.

    I'm debating sending it back and going with a 40hp rotary phase converter. The benefits are I can add a milling machine and lathe down the road as a 40hp has like 90 amps to play with.

    A 40hp 3 phase motor with the correct capacitors can be powered via 220 right? I found a couple cheap 40hp 3 phase motors and ebay has 40hp phase converter panels for $200-$300. This way I can route a breaker panel and just plug in machines.

    The only negative is a 40hp motor is massive and likely loud. I will have to figure out where to place it in my 2 car garage that's pretty packed already.

  2. #2
    Join Date
    Jun 2008
    Location
    So Cal
    Posts
    3,739
    Will you be able to start and run a 40 hp RPC on your residential service.If so I'm jealous.
    When I start my 5hp Oliver with a 10 hp Kay RPC.The lights in the house flicker.
    Aj

  3. #3
    What kind of service do you have available? I would worry about having enough power to get the RPC up to speed without tripping a main breaker or causing a massive voltage droop in your house.

    RPCs are loud, waste energy at idle, and take up room...

    I'd vote for the VFD. The transistors and control ICs in most VFDs are all made by reputable manufacturers - it's just the UI and mechanical stuff that "Huywang" added.

  4. #4
    I don't know RPC's from RPG's, but just a quick EEeeGAD-factor: I believe a 40hp motor at 230VAC/1-phase will pull about 175 Amps at full load. Figure ~1.5X for inrush at starting (=262A.).

    I think it was pretty typical to install a 100A. service panel in many pre-1970 homes; they have gotten bigger, but 200A. is probably the typical 'big' panel (not counting McMansions).

    Don't know where you're located, but you may dim the light for a couple of blocks in all directions...???

  5. #5
    Join Date
    Dec 2010
    Location
    WNY
    Posts
    9,648
    40 HP? Can a 200 amp panel start that?

    Food for thought, I just finished installing an upgraded static phase converter on my friends 3 ph, 5 HP, 16" Zefam jointer today. By upgraded I mean the guy who built it, WNY Phase Converters who I talked about earlier, used much larger and higher voltage rated capacitors than in a standard unit. The standard 3- 5HP unit took 5 - 6 seconds to bring the cutterhead up to full speed; the upgraded unit does it in 3 seconds. It didn't cost much; on the order of $100. Wiring it was simple and it operates just like any other motor, but at only 2/3's the rated HP. We jointed a couple of 12" wide boards on it and could not discern any appreciable loss in rpm compared to our other jointers. A planer is a different animal but if yours is only 15 - 18" wide 2/3's of 5HP would be more than adequate unless you wanted to take huge cuts with it.

    I would try the VFD you bought. Lots of folks have had success with it on at least 3 HP motors. If it doesn't work, I'd consider a static phase converter next, or a single phase motor, as better options than a giant RPC.

    John

  6. #6
    The 40hp is a 3 phase motor and pulls I believe 55 amps, says FLA 110/55 which I believe refers to volts listed 190/380. I'll have to look and see what power I have at my panel.

  7. #7
    10 HP roto blips to 165 amps for a split second no issues idles at around 17 no load, is quiet not noisey and and would start that jointer full speed in less than 2 seconds. Ive never timed it but it started my combo machines and they are a bigger shaft with a saw and mortiser other end. Should have tried one of them when it was on true 3 phase 600 to see if it was any faster on start up, at some point shaft size or load is going to dictate how quick anything comes up to full RPM its not like starting a table saw mass. it will start a 10 hp machine fine and supposed to run up to 30 amps total or now im thinking its HP but then they are usually about the same at 600. for a lark I started up I think five machines total one day and no load all running was 20 some odd amps maybe 23 not sure could check they act some how as ballasts at some point. Every one quotes different numbers but thats my experience on a Delta TME brand. Dont know why you need 40 HP im sure my unit would run all you talked about and at once, what is your voltage. People have good results with VFD's I know zero about them but there is lots of info on them and a fair bit on the Canadian site some pretty bright people there as well as here.

    Thinking about it most were 575 in the five running two were 220 3 phase so dont get if they act as ballasts for each other how that works when they are different voltages. there are some smart guys around both sites that understand lots about these things.
    Last edited by Warren Lake; 05-25-2017 at 9:43 PM.

  8. #8
    Join Date
    May 2016
    Location
    North -Eastern Ontario, Canada
    Posts
    271
    I have a three man custom shop - far enough off the main line closest to my shop that we couldnt be fed with 3 phase. I have worked my entire life (since the 80's) being fed with 600V three phase, so when I moved shop and set up here, I was into the unknown.

    Based on my equipment, my machinery supplier (Akhurst) suggested a RPC with a 25 Hp single largest motor, and up to 75 Hp combined. Been running it 6+ years now, daily, on at 8am and off at 5pm. No issues, all I do is grease the main bearings on the idler once a year.

    We run many machines in the 5 to 10 Hp range. I often run the panel saw (9 Hp), dust collector (7.5 Hp), planer or jointer (7.5 Hp each), 5Hp 10" saw, or one of many smaller sanders, the 10 Hp compressor and if Im also spraying, the booth exhaust (5 or 7.5 Hp) or the shaper (7.5Hp).. basically three of us where often we are all working on a different machine.

    If I run the widebelt (20 Hp), and also my CNC with 10 HP vacuum, DC, compressor etc everything still runs fine.

    Im fed by a 200A 240V service. I of course still have lighting (quite a bit as its a 6000 sq ft building), some hot water heating in the winter, hand tools etc. fed off the 120V single phase and 240V single phase main panel.

    We've had pretty decent luck with this set up. I had my doubts when setting things up, but not anymore.
    Andrew J. Coholic

  9. #9
    Join Date
    May 2003
    Location
    NW Arkansas
    Posts
    180
    You can start large phase converters with really small pony motors. The amp draw on start up is very small.
    Larry

  10. #10
    Join Date
    Feb 2011
    Location
    Central WI
    Posts
    5,666
    You can barely run a 30 hp Phase perfect on 200 amp service and have left overs for lights and stuff. Most RPC also have a minimum and maximum size motor they can run and still maintain a decent balance. Unless your service is 200 amps @ 380 you don't have the power. 110 amps at 190 ( weird voltage ) is three phase so the single phase source needs to be at least 1.73 x higher. Dave

  11. #11
    I just put one of those vfds on a 5hp DD jointer. Simple to wire up and set up. only thing I had to figure out was how to wire up a remote start stop station.

  12. #12
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    9,885
    To get from three phase amps to the needed single phase input take the three phase motor nameplate amps and multiply it by the square root of three to get single phase amps need. this assumes the phase converter is 100% efficient. Which it will not be ever. Especially as the hp goes up the heat loses and cooling fan power wasted goes up.

    the square root of three is 1.73. so 110 x 1.73 = 190 FLA. Of course your voltage is a little off the nameplate since you most likely have 240 volts single phase, not 190 volts. So the FLA may be about 20 percent over that 110. that works out to 228 amps. But you better allow for at least 400-500 amps single phase on startup. I think the heavy cables to wire you 40hp rpc will cost more then 5-6 5hp vfds. Heck I bet the 400 amp switch will cost more then one or two VFDs. And each machine will need a disconnect switch.
    I found. site that said 400 amp cable will cost 10.50 per foot. I believe that is for three conductors. The Polaris connectors for the cable connections will probably be as much as one 5hp VFD.
    Bil lD.
    Last edited by Bill Dufour; 05-26-2017 at 1:00 AM.

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