new addition, big for me lathe - Page 2
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  1. #21
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    Quote Originally Posted by neckyzips View Post
    ok, if i understand this right, RPC is better than VFD, any ol RPC will get the job done, worst case the lathe starts slow with a heavy chuck etc, and the old 3 hp on the lathe is stupid simple and likely not to care so much about a leg being unbalanced; and RPC is much less expensive to run than main line 3 phase would be just to have. i am assuming the same to be true with the clausing 8540.

    now what happens when a nice used haas V1 mill shows up
    Yah figure yer first Pilgrim on this?

    Folks upgrade to a right-sized "CNC grade" RPC.. a honkin' great oversized "BFBI" RPC...or ... mortgage the family and buy a Phase-Perfect.

    Rumour has it the Haas isn't even the hardest among the CNC tribe to keep on yer side. Some CNC critters are fussy by make, rev level, and "era", others much less-so.

    Any CNC maker as WANTS to do can build their whole system more or less "agnostic" to what the power source looks like, so long as there is "enough" power.

  2. #22
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    A 3hp VFD is probbaly cheaper then a rotary converter and you do not have to pay for switch gear and disconnects which a rotary requires for each machine. A VFD is rated as a disconnect and a breaker panel, overload, etc. 3hp is the magic size where VFD costs quickly go up. A 3hp VFD can run a 5Hp motor just fine but you will only get 3hp out of it. A rotary has to be sized to the expected load.
    My 3hp lathe ran fine on a one HP VFD that came with it since I was lightly using the lathe. I upgraded to a 3HP VFD and used the one HP VFD for a different machine.
    Variable speed is not really a lathe issue nor is instant reverse. The power braking can be nice when threading.
    Bil lD

  3. #23
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    Quote Originally Posted by GregSY View Post
    Around here, they seem to want over $300/month in 'demand charge' whether you even use the 3 phase of not. Then, there is the cost of actually running it to you which starts at around $3,500....even if all they need to do is flip a switch.


    Where are you guys paying those high prices.
    I bought a home in Sandy, Oregon that has three phase going to the shop (separate meter) and split phase going to the home (separate meter). Since I'm not running my machines every day, my shop bill is approximately 32 dollars a month. When my wife runs her ceramics kilns I get bills up to about $40 maximum. I do use the lights and the woodworking equipment 3-4 days a week. Of my $32 dollar bill, about $18 are standby charges.

  4. #24
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    Quote Originally Posted by GregSY View Post
    Around here, they seem to want over $300/month in 'demand charge' whether you even use the 3 phase of not. Then, there is the cost of actually running it to you which starts at around $3,500....even if all they need to do is flip a switch.
    I am embarrassed, I probably burn more in led lighting then my main machines use, all 10hp an under.

    It's about 250 just to have the pleasure of getting even more hosed when the bill shows up. Last month was 600 bucks and I really didn't do anything different.

    I spent two days getting passed around the little city office building trying to find someone that actually had real #s for the meters, but alas, nothing. I am looking into going in on an energy auditor with the 3 businesses around me. One uses about 30k a month.

    Sent from my SM-N960U using Tapatalk

  5. #25
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    Quote Originally Posted by Ivan Vegvary View Post
    Where are you guys paying those high prices.
    Where we have distant mine-mouth thermal COAL, closer not-cheap twin NUKES at Lake Anna, PUMPED storage from them for peaking at Smith Mountain Lake, only "some" input from solar PV or wind... and one HELLUVA lot longer distance from Grand Coulee dam than you have?

    Also a denser population to suck more power and inspire gawdawful higher costs to run and maintain the routes to distribute it, so many areas being built-up densely.

    Not knocking VEPCO/Dominion.. they do a FAR better job than several of our adjacent states... or DC proper. It just isn't a job that's "easy".

  6. #26
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    I retired my rotary and reverted to a static converter I bought as a stop-gap.

    WNY Supply Online store for static phase converters

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    Quote Originally Posted by MrWhoopee View Post
    I retired my rotary and reverted to a static converter I bought as a stop-gap.

    WNY Supply Online store for static phase converters
    Cheaper to have just cut the cord and "retired" the lathe, so at least the motor could live to some possible future return to duty.

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    Quote Originally Posted by Bill D View Post
    A 3hp VFD is probbaly cheaper then a rotary converter and you do not have to pay for switch gear and disconnects which a rotary requires for each machine. A VFD is rated as a disconnect and a breaker panel, overload, etc. 3hp is the magic size where VFD costs quickly go up. A 3hp VFD can run a 5Hp motor just fine but you will only get 3hp out of it. A rotary has to be sized to the expected load.
    My 3hp lathe ran fine on a one HP VFD that came with it since I was lightly using the lathe. I upgraded to a 3HP VFD and used the one HP VFD for a different machine.
    Variable speed is not really a lathe issue nor is instant reverse. The power braking can be nice when threading.
    Bil lD
    Bill,
    i like the speed change of the lathe and it utilizes the brake to make that work, my understanding is with a VFD i would have to incorporate that into the wiring somehow. then to run the mill i would have to have a second VFD, or just one RPC to run each separately?

  10. #29
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    The reason I didn't mention VFD's is the OP said he wanted to multi-use the RPC and while you can do that with a VFD, it gets more complex than it sounded like he wanted.

    As for 3 phase....let me give you an example. My friend owns a fab shop with 3 phase, so he's well familiar with it. He bought a much smaller building down the road and considered putting some of his less-used machines in it. The power was cut off as the building had been sitting vacant. There was already 3 phase on the pole...you can reach out the window and touch the pole, so it's close. The power company wanted a little over $3K to 'bring in' the 3 phase, and the minimum monthly charge would be over $300 even if he didn't use it. (That is where I got the numbers I used earlier). This was just in February so they are recent prices. He just had them 'bring in' single phase 240v for pennies and it's similar to a house's electric bill.

  11. #30
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    Quote Originally Posted by neckyzips View Post
    Bill,
    i like the speed change of the lathe and it utilizes the brake to make that work, my understanding is with a VFD i would have to incorporate that into the wiring somehow. then to run the mill i would have to have a second VFD, or just one RPC to run each separately?

    VFDs are commodity items, and are inexpensive. You put a dedicated one on each machine you have. You never switch the output, so this is hard wired to the motor.
    I started out using a home built RPC, had to start that before the mill or lathe, and another noise generator in the shop. It worked, but the variable speed on the mills and lathes, as well drill presses, and the soft start, is worth the time to wire them in.
    I have two machines with antique motors, the early VFDs could damage them, but now they have edge rate controls in the IGBT transistors that limit the Ldi/dt inductive voltages generated.
    Also, I set my VFDs to free wheel, and not brake the machines on stop. But then I don't have any huge inertial load, outside of the 12inch chuck on the lathe. That has a foot brake and the VFD gets a stop signal so you don't want it to fight the brake vs decelerate drive of the motor it would normally do.

    I don't know about the quality of the VFD in post #12. That looks like the infamous Huang VFD repackaged. It is not a sensorless vector drive, so low RPM (<30Hz) will not have the desired torque. Maybe they have improved their component quality. The only one I purchased had an input capacitor fail on just testing a 3HP motor I had, unloaded, while testing at low RPMs, loud bang. I found Dealers Electric to have affordable VFDs (dealerselectric.com Teco namebrand).
    For $207 plus shipping Teco-Westinghouse, L510-203-H1, 3 HP, Variable Frequency Drive 230 Volt, 1 Phase Input, IP20, at Dea
    A quality drive.

  12. #31
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    Quote Originally Posted by Ivan Vegvary View Post
    Where are you guys paying those high prices.
    Demand charges! ~ $10 per kW demand charge. Demand is a continuous load for >= 15 minutes. So 4500 watt (4.5kW) water heater has the element running for 15.1 minutes? That is 4.5 kW * $10 per kW demand = $45 that month just for availability of power to run the water heater. That doesn't buy any electricity, just access to it. Now take the whole shop on a busy day. 15 HP CNC lathe, 15 HP CNC mill, air compressor, heavy TIG welding, lights, computers, air conditioning, etc. So my 200 amp 208V 3PH service ... if I used 200 amps for >= 15 minutes ... would be $720 in demand charges.

  13. #32
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    I put a load reactor between the VFD and the motor on my lathe. It should filter out any high freequencies. Cheap on ebay. I do not really remember why I thought there was a problem.
    Bil lD

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    Quote Originally Posted by kb0thn View Post
    Demand charges! ~ $10 per kW demand charge. Demand is a continuous load for >= 15 minutes. So 4500 watt (4.5kW) water heater has the element running for 15.1 minutes? That is 4.5 kW * $10 per kW demand = $45 that month just for availability of power to run the water heater. That doesn't buy any electricity, just access to it. Now take the whole shop on a busy day. 15 HP CNC lathe, 15 HP CNC mill, air compressor, heavy TIG welding, lights, computers, air conditioning, etc. So my 200 amp 208V 3PH service ... if I used 200 amps for >= 15 minutes ... would be $720 in demand charges.
    It's great, isn't it?

    Sent from my SM-N960U using Tapatalk

  15. #34
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    A very good non-Chinese VFD is the WEG CFW series. These cost a little more than the Chinese VFD's (such as TECO) but are better built and have decent instruction/programming manuals. They are also stocked throughout the USA.


    For example:

    WEG VFD CFW300B10P0B2DB20 ENCLOSURE CFW300 10 AMP 1PH 200-240V 3 HP | eBay


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