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  1. #61
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    Default VFD switching on a Hercus 260

    Thanks Chris. It's a Hercus 260 with a TEFC motor. 1360 rpm. Does that make it 4 pole?
    Chris
    Chris

  2. #62
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    Quote Originally Posted by jack620 View Post
    Thanks Chris. It's a Hercus 260 with a TEFC motor. 1360 rpm. Does that make it 4 pole?
    Chris
    Yes

  3. #63
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    Default VFD switching on a Hercus 260

    Great, I'll set the max drive freq to 100Hz.
    Chris

  4. #64
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    just found this if anyone's interested vfd items - Get great deals on Pumps Motors items on eBay Stores! looks like a new version of the huan yang with now a detachable control panel
    usual disclaimer no personal interest
    john

  5. #65
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    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Quote Originally Posted by Pete F View Post
    I can't imagine a VFD being able to stop a lathe so suddenly it would unscrew a chuck, especially not without some pretty serious braking resistors. That energy needs to go somewhere.
    I've only just read through the whole thread. I can say 100% for sure you will unscrew a large chuck with a fast ramp down and DC braking. I have done it...not fun. 8" chuck, 4 sec ramp down to 10hz then braking. Chuck comes off.......

    With a small chuck its not a problem. The 5" doesn't move even with 2 sec ramp down and hard DC braking. I have mentioned it before but i have a switch to change between ramp down speeds. One setting set to 4 sec or so, for larger chucks and high speeds, one setting 2sec for lower speeds and smaller chucks. The mars will now happily run to 2.5k with the 5" chuck or collet chuck. Smooth as silk. I have a resonate noise at around 30hz though, everything shakes slowly in out out, like d d d d d d d............d d d d d d d..........changing some of the big CI pulleys to alloy to see if that fixes it. Not there with just the motor running, but comes in with the countershaft spinning but not the spindle.

    It may have been in Grahame's Thread about letting the motor coast to stop, for the Huanyangs it is Pd26.

    Cheers,
    Ew
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  6. #66
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    Quote Originally Posted by Ueee View Post
    ................... I have a resonate noise at around 30hz though, everything shakes slowly in out out, like d d d d d d d............d d d d d d d..........changing some of the big CI pulleys to alloy to see if that fixes it. Not there with just the motor running, but comes in with the countershaft spinning but not the spindle. .......................Ew
    Many VFD's have a feature, that lets you skip or exclude one or several frequency ranges from the ramp. For example in your case, you could exclude 29-31Hz. The motor speed then ramps up normally to 29Hz, then it makes fast transition to 31Hz. Or in other words, it is like if the VFD does not allow you anymore to put the speed pot to the position that corresponds to 30Hz. It works both ways accellerating or decellerating. You got to read your VFD manual if such frequency skip function is available. I run 5 different VFD's makes/types in my workshop, and all of them allow for one or several frequency ranges to be skipped.

    I particularly observed that non-VFD rated motors often have one or two speeds at which a resonance can be heard. It is sometimes loud enough to be disturbing. The sound is like if a piece of metal was vibrating against the motor housing. I assume the sound originates indeed from the edge of one or several stator laminations that have not been properly impregnated with resin, maybe because of an air bubble. VFD rated motors are I believe always carefully vacuum impregnated to remove air bubbles in the resin, but these are usually too expensive for home/hobby use. Chris

  7. #67
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    Quote Originally Posted by Ueee View Post
    I've only just read through the whole thread. I can say 100% for sure you will unscrew a large chuck with a fast ramp down and DC braking. I have done it...not fun. 8" chuck, 4 sec ramp down to 10hz then braking. Chuck comes off.......

    Cheers,
    Ew
    How hard are you installing the chuck? I can use my lathe when running in reverse (carefully of course), and have yet to have it unscrew. To install the chucks I spin them on and use their own inertia to seat on the register. Firm enough, yet will loosen with a firm tap on the key. It's a definite seating when they go on.

    Pete

  8. #68
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    Default VFD switching on a Hercus 260

    I've had my 3 jaw unscrew itself and fall onto the ways and then the tray. I was using the lathe in reverse to "run in" a small engine I'm building. Fortunately it was only running around 150RPM. What happened was each time I hit start it would unscrew a little until it eventually fell off. I was concentrating on the motor, not the chuck so I didn't see it coming.

    I also screw mine on and use its inertia to seat it. There's no doubt in my mind that a rapid stop would cause it to unscrew. The 4 jaw at high speed would land in your guts. Maybe the stop times achievable with a VFD aren't quick enough to cause the chuck to break its grip, but I don't want to find out.

    Chris
    Chris

  9. #69
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    Default VFD switching on a Hercus 260

    Duplicate post
    Chris

  10. #70
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    My VFD arrived today and I hope to get stuck into installing it tomorrow.

    I need to get my head around this 2-wire vs 3-wire control issue. Looking at the manual it appears that 2-wire fwd/rev control is used if you have a rotary selector like my Hercus does. Rotate the knob left and the motor starts in reverse. Rotate it back to centre and the motor stops. Rotate it right and the motor starts in forward.

    I think 3-wire control is used when you want to control fwd/off/rev with pushbutton switches?

    So I'm planning to use 2-wire control with the rotary knob as my fwd/off/rev control.

    I will use the original green and red pushbuttons to control the contactor which will feed the-single phase input to the VFD. Push the green button and the contactor latches and the VFD energises. Push the red button and the contactor opens and the VFD loses power. I envisage pushing the green button when I first walk up to my lathe. When I'm done for the day I push the red button and de-power the VFD. While using the lathe I will only be using the rotary knob and the speed control pot (unless something goes wrong and I want to shut off power to the VFD- then I hit the red button).

    In addition to these controls I will wire my foot operated e-stop and the lathe's headstock lid safety switch to another logic input. Not sure how I'll configure that yet.

    Does this sound logical?

    Chris

  11. #71
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    I still dont understand Chris's dislike of 2 wire control so I dont see a problem with that side of things.

    I dont like using the VSD e-stop circuit as its NO........But if you are going to use it most of the time to stop the lathe then I guess the chances of it failing and you not konwing about it until you needed it are "unlikely"...............your machine.

    Stuart

  12. #72
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    Hi jack620,
    For your Emergency Stop switches, wire the NC(normally closed) contact on the E/Stop Button and the NC(normally closed) contact on the Foot Operated E/Stop in series into the Control Contactors Positive Coil Terminal. This way you will dropout the Contactor when you hit the Emergency Stop taking power off the VSD, note that the Lathe will coast to stop as you will not have any VSD control on the Motor.
    This type of Emergency Stop arrangement is equal to a Safety Category 1 as found in the Australian Standard for Machine Guarding AS4024-2006, this maybe sufficient for you in your situation as its not an Industrial Environment.

    Regards,
    Keith_W.

  13. #73
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    Stu,
    I'm also still trying to get my head around the 2-wire/3-wire thing. My plan is not to use the e-stop in normal use. My plan is to use the rotary selector as my on/off switch. The screenshot below is from the Altivar setup guide. 2-wire seems like the method to use for a rotary selector. I'm certainly not averse to using 3-wire, I'm just not sure how it would be wired with my rotary switch.
    Screen Shot 2013-06-25 at 8.45.09 AM.png

    Keith,
    thanks. I reckon I'll do it the way you describe. That way if the VFD goes haywire, hitting the e-stop kills it. It means my e-stop works exactly the same is it does now (coast to stop). While a very rapid e-stop would be nice, as I've said earlier, I don't think it's advisable with my threaded spindle.

    If I change my mind it's a simple process to reconfigure the e-stops later.

    Chris

  14. #74
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    Hi Chris,

    "My plan is not to use the e-stop in normal use" I disagree, but that is up to you.(of course what you choose to call the foot pedal is up to you also).

    One thing to look into. The self check time on the Huanyang VSDs is about 5 seconds, so if you wire the lathe as per Keiths post and you put the headstock cover in the e/stop circuit, you'll have a 5 second wait each time you change speeds.(of course your VSD might not take that long, I cant remember what my Teco takes)

    Assuming your switch is a single pole double throw center off, I dont see how you could use it with 3 wire control without adding at least a couple of diodes. (assuming the controls are 24VDC, which I think they are on my VSD's but I have no idea about yours......and my memory sucks anyway)

    Stuart

  15. #75
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    Quote Originally Posted by Stustoys View Post
    The self check time on the Huanyang VSDs is about 5 seconds, so if you wire the lathe as per Keiths post and you put the headstock cover in the e/stop circuit, you'll have a 5 second wait each time you change speeds.(of course your VSD might not take that long, I cant remember what my Teco takes)t
    Good point. I forgot about belt changes. Although I hope they will be far less frequent than they are now. Perhaps a better system would be foot switch to contactor coil and headstock cover to a logic input? Then the VFD stays powered during a belt change.

    My VFD uses 24VDC for the logic inputs.

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