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Thread: How I put a VFD on a drill press for no more belt changes

  1. #31
    Quote Originally Posted by Bill Adamsen View Post
    Very nicely done Dan! That enclosure doesn't appear to be NEMA, how does someone determine if they need a NEMA enclosure or the VFD can survive in the shop conditions without?
    If NEMA was needed... I think a UL on VFD would be too (as well.. Final inspection on set up) . I don't think this set up meets UL requires.

  2. #32
    Quote Originally Posted by Bill Adamsen View Post
    Very nicely done Dan! That enclosure doesn't appear to be NEMA, how does someone determine if they need a NEMA enclosure or the VFD can survive in the shop conditions without?
    Quote Originally Posted by Frank Pratt View Post
    Looks like a NEMA 1 enclosure to me.
    Quote Originally Posted by Matt Mattingley View Post
    If NEMA was needed... I think a UL on VFD would be too (as well.. Final inspection on set up) . I don't think this set up meets UL requires.
    NEMA type-ratings run from 1 to 13 with several sub-catagories defined by adding letters (i.e. '4X'). Most smaller VFDs are designed with the intent that they are going to be integrated into a MCC (motor control center) or a control panel (enclosure). The MCC or control panel would have it's own NEMA type rating - suitable to the installed location. Since the 'integrated' VFD is thus protected from the environment, the VFDs are typically built to a NEMA-1 standard, intended only to protect personnel from incidental contact with live electrical parts (sometimes called 'finger-safe').

    To enclose a NEMA-1 VFD, I would recommend a NEMA-12 enclosure as a minimum for a professional woodworking environment, but as with all things, it will cost extra.

    I haven't read the manual for Dan's VFD selection, but a quick look at the photo makes me think it is NEMA-1. In a hobby setting, it will do fine with minimal care (use clean, dry air to blow the heat sinks, fan, and circuit boards clear of any dust accumulation). Biggest thing is protect it from water drips or spray. But all said, I'd grab a cheap NEMA-12 box and be done with it.

    Edit: Putting a NEMA-1 VFD inside a NEMA-1 enclosure, certainly provides some extra safety margin, but I'm not sure it improves the NEMA rating for purposes of code compliance. ...I'd have to do some more research on that And very neat install Dan - I want one!
    Last edited by Malcolm McLeod; 01-13-2017 at 12:44 PM. Reason: NEMA-squared?

  3. #33
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    All that stuff is way beyond me. When I added a VFD I started with a 3450 RPM 3 phase, 1.5 hp motor. Had dog squat power at low RPM and could stall the motor by grabbing the chuck. I played around with the belting and finally switched to a 1725 RPM 2 hp motor. With the right belting I ended up with satisfactory low RPM power. I sacrificed a fit of high RPM, but never used it that much anyway.

    I hung the VFD in back below the motor. The VFD has a pop-out control that can be remote mounted with the proper cable, but I didn't see to have immediate access to all those functions. So I just put a speed pot, a run switch, and tach up front. With a separate tack, I don't need to worry about slipping, etc. It is still not perfect but does what I need.






  4. #34
    Join Date
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    Gaithersburg, MD
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    Very interesting and informative thread. I am also lazy switching belts and hate doing so. Recently was doing research for myself to do similar conversion. I'm still not clear about motor choice. From what I gathered, it seems to me that in order to get great torque at low speed one needs inverter duty motor, which can handle low frequency well. Standard and especially older motors will not work that well under VFD.
    Is it true? What you thought experience on that matter?

  5. #35
    Quote Originally Posted by Yuri Sadykov View Post
    Very interesting and informative thread. I am also lazy switching belts and hate doing so. Recently was doing research for myself to do similar conversion. I'm still not clear about motor choice. From what I gathered, it seems to me that in order to get great torque at low speed one needs inverter duty motor, which can handle low frequency well. Standard and especially older motors will not work that well under VFD.
    Is it true? What you thought experience on that matter?
    A 'inverter duty' motor is not mandatory. You can use nearly any good quality 3-phase motor with a VFD.

    Sometimes you can experience problems with the motor overheating, due to inadequate air flow. This can occur IF you run for extended periods at low RPM - typically below 25% (15hz) of the rated motor speed. As always, every user is different. How long? How slow? What load? All these weigh into the mix.

    Dan may have already worked thru this, but I'd be tempted to leave all the normal sheaves on the DP, and set the belts to run at ~1000 RPM at the quill. And then leave them alone.

    Now install a VFD. At 25% VFD output, I'd have virtually no concerns about overheating, I have decent torque (see Dan's OP), and I'd get ~250 RPM (suitable for 2" or so Forstner).

    At 100% output, I get full torque and ~1000 RPM.

    This 25%>100% range, would cover 95% of the work I do.

    For short runs, I can drop to 10% output (100 RPM).

    On the other end of the scale, most VFDs can be configured to run at up to 300% of 'rated' RPM; a few to 600%. So with the same set-up, I can get up to 3000 RPM. Motor bearings take a beating, but again, for limited runs this will work.

    I'm now able to cover 99.9% of the work I do. For the once-in-a-lifetime needs, I can move the belts (assuming I remember how).
    Last edited by Malcolm McLeod; 01-17-2017 at 7:31 PM. Reason: spelling

  6. #36
    Join Date
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    Yuri,

    I am not an engineer but have a number of VFD in my hobby shop and none are on inverter duty motors. As far as duty is concerned, the motors I have are not being pushed too hard. I have a 1 hp on the drill press, and 1.5 hp on the lathe and speeds are not fluctuating wildly and neither motor is being employed in a 24/7 severe basis as a pump, compressor or HVAC unit would be. While an inverter duty motor would be the gold standard, my hobby usage is unlikely to ever result in motor damage.
    [SIGPIC][/SIGPIC] Erik

    Canada's Atlantic Paradise - Prince Edward Island

  7. #37
    I agree with Erik and Malcolm. Especially on drill presses, where the "duty cycle" is very low and the mechanical load is very low, I think you'd be hard-pressed to do anything "wrong" - it will work fine. Maybe in continuous, demanding applications it would matter, but not here.

    I could have left the step pulleys in place, as Malcolm suggests, but in my case, the bore in the step pulley wouldn't fit my new motor, and step pulleys are much more expensive than singles. So I just bought the single.

  8. #38
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    Malcom,
    thank you for the input. I use my drill press (Delta 17-965) in my hobby woodshop. No prolonged usage, so my concern about overheating is minimal. I want some range in rmp. High rpm (let say ~2000) for drilling with small drills with very low torque requirements. Low rpm mostly for hole saw/drill, forstner bits, occasional thread tapping. Basically, standard set of operations.
    Main thing I need from the motor is that it should be capable to work at 25% or less of rated RPM. I read somewhere that standard (older especially older) will not work at all at 1/3 or even 1/2 of normal RPM.

    I can buy that bundle (motor with VFD) ~$300
    http://dealerselectric.com/three-qua...t-Package-.asp
    where motor Features:
    · NEMA MG1-PART 31 Inverter Duty 15:1 Constant Torque
    · Service Factor 1.15
    · IP55 degree of protection
    · VPI Impregnation
    · Internal Tropicproof
    · F1, F2, & F3 convertible
    · Class F insulation
    · Dual Rated 60/50Hz
    · Warranty: 3 Years
    · CSA approved for Class I ; Division 2 ; Groups A,B,C & D,T3

    though I can save $100 for the bundle if I just pick up standard/older similar motor.

  9. #39
    Quote Originally Posted by Yuri Sadykov View Post
    Main thing I need from the motor is that it should be capable to work at 25% or less of rated RPM. I read somewhere that standard (older especially older) will not work at all at 1/3 or even 1/2 of normal RPM.
    This is not completely true. I'm not exactly sure what you're considering "older" but ideally it comes down to cooling. It really depends on its design. If it is a
    2 pole (3600 RPM)
    4 pole (1800 RPM)
    6 pole (1200 RPM)
    8 pole (900 RPM)
    10 Pole (720 rpm)
    12 pole (600 RPM)
    16 pole (450 RPM) these are all numbers at 60 Hz (what the power company presently is giving us in North America)
    A typical 4 pole (1800 RPM) Motor can run at double the speed and usually the bearings are rated for 5000 RPM-ish and the built-in fan is doing the job it's therefore. Now if you take the same motor and run it at half speed 900 RPM with a full load torque the windings and Armature will start overheating causing breakdown of bearings, Greece, breakdown of winding shellac, linear expansion of armature... and the list goes on. But if you can adequately cool the motor with an additional fan, you can achieve rpm in the 10% range. Sensor less Flux vector VFD's work better in the situations.

    Quote Originally Posted by Yuri Sadykov View Post
    I can buy that bundle (motor with VFD) ~$300
    http://dealerselectric.com/three-qua...t-Package-.asp
    where motor Features:
    · NEMA MG1-PART 31 Inverter Duty 15:1 Constant Torque
    · Service Factor 1.15
    · IP55 degree of protection
    · VPI Impregnation
    · Internal Tropicproof
    · F1, F2, & F3 convertible
    · Class F insulation
    · Dual Rated 60/50Hz
    · Warranty: 3 Years
    · CSA approved for Class I ; Division 2 ; Groups A,B,C & D,T3

    though I can save $100 for the bundle if I just pick up standard/older similar motor.
    Now my drill press has a 5 hp motor. What would be your suggestion? this question is open for anyone to answer. What would be the cheapest VFD single phase input (non-D-rated) three phase output that has sensorless vector control?

  10. #40
    Quote Originally Posted by Matt Mattingley View Post
    Now my drill press has a 5 hp motor. What would be your suggestion? this question is open for anyone to answer. What would be the cheapest VFD single phase input (non-D-rated) three phase output that has sensorless vector control?
    Here's a 2HP example with SVC for $110:
    http://www.ebay.com/itm/361155386082...%3AMEBIDX%3AIT

    You really have a 5HP motor on a drill press?


    Also, I have a really strange question: Why do people keep typing "D-rated"? I've never seen that, before (I mean, everyone I know writes "derated"). Is it common shorthand?

  11. #41
    Quote Originally Posted by Dan Friedrichs View Post
    Here's a 2HP example with SVC for $110:
    http://www.ebay.com/itm/361155386082...%3AMEBIDX%3AIT

    You really have a 5HP motor on a drill press?


    Also, I have a really strange question: Why do people keep typing "D-rated"? I've never seen that, before (I mean, everyone I know writes "derated"). Is it common shorthand?
    blam it on SIRI! It is "her" fault.

  12. #42
    Join Date
    Mar 2003
    Location
    San Francisco, CA
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    This weekend I Friedrichized my drill press. Like Dan says, it was pretty straightforward. The drill press is a Delta 17-959L, about ten years old. I bought a VFD-plus-motor package from Dealers Electric --http://dealerselectric.com/three-quarter-HP-3600-RPM-115-Volts-Input-Package.asp. 3/4 horse motor, 115 volt input, vector drive, speed control by a knob not pushbuttons. The motor footprint matches the drill press, so it just bolted in place. The motor has a 5/8" shaft, so the OEM pulley did not fit. Ten bucks to McMaster-Carr brought me a pulley. This VFD, unlike Dan's, cannot separate into two pieces, so the whole VFD went on the front of the drill press in place of the OEM on/off switch. In the photos, this placement looks like it might be in the way, but it isn't. My eyeball height is just about in the middle of the VFD, so my forehead has to touch the VFD before it interferes with my sightline to the workpiece. I hoped to reuse both OEM belts, but it turned out that one of them would be too long. I bought a link belt for a quick fix.

    Fast, slow, and anyplace in between -- all just at the twist of the knob!

    drillpressA.jpg

    drillpressB.jpg

  13. #43
    Very nice, Jamie! That Dealer's Electric motor+VFD package is a deal, and I'm glad the motor fit your drill press. Did you get the 3/4HP version?

  14. #44
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    Mar 2003
    Location
    San Francisco, CA
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    Quote Originally Posted by Dan Friedrichs View Post
    Very nice, Jamie! That Dealer's Electric motor+VFD package is a deal, and I'm glad the motor fit your drill press. Did you get the 3/4HP version?
    Yes, I bought the 3/4 horse motor. There was no motor plate on the OEM motor, so I just guessed as to what its horsepower might be. But truth be told, I suspect 3/4 hp is overkill for the work I do.

  15. #45
    Cruel and usable punishment should be banned in TOS!! You people!! ..You're costing me money!

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