Lathe VFD Addendum: How to Tune Acceleration and Braking
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- เผยแพร่เมื่อ 11 ก.ค. 2018
- Today we'll spend a few minutes tuning the new VFD acceleration and deceleration times. We'll talk about what limits startup and braking speed and do some experimenting to find the best settings for this lathe, motor and VFD combination.
If you'd like to do this upgrade on your lathe, here are some of the parts I used:
*This site contains affiliate links for which I may be compensated
Teco-Westinghouse L510 1HP VFD (Amazon*): amzn.to/2F2X7a8
Leeson 1800RPM D80 Motor: www.electricmotorwholesale.com...
20A Power Line Noise Suppressor (Amazon*): amzn.to/2HAcaxs
Hammond 12x12x6 Box: www.wistexllc.com/chko12126-1...
James,
A fantastic Series on the lathe VFD. I have inherited an L510 with a South Bend Heavy 10 and have started to set it up. Your series have saved me a ton of time. I now have a strategy to deploy the equipment.
Thank you for being so kind as to post so much informative footage for the lathe VFD.
All the best.
No words to appreciate your effort
James - I want to say I really enjoy your videos. Everything seems so well thought out and presented clearly . I appreciate the commentary on not only what you are doing but why you chose the methods you do. ( They are also a good "fix" when I cant spend time in my shop.) Thank you .
Thank you! I appreciate the feedback.
Hi... Great work and great series of videos. I love your attention to detail. Keep up the great work mate 👌
nice videos... Southbend 10L getting the same VFD.. I got it installed and working and now learning about the VFD.. most helpful thanks...
You're welcome.
Very very nice project. Excellent design and fitment. Huge increase in lathe usefulness.
This is all amazing. I too have the G0602 and I am completely copying you - same VFD, motor and almost same settings. Thanks for this! (I'm having an issue with the motor starting in reverse, but I'm still working on that)
Wow, that's pretty nice your VFD displays the voltage and current. I used to have a more expensive Hitachi and I don't think it had those diagnostics. Very interesting method of optimizing.
Awesome video! Very well done once again.
Great content James
the most informative video's I've seen yet, helped me navigate my VFD ,for my instructions aren't as detailed, tks.
This is a great series of improvements to the G0602 Lathe. I have that machine and am going to make this conversion. I have the motor (Marathon R313A) which is comparable to the Leeson and I have the Westinghouse VFD. My only comments are that it would be helpful if a bill of materials was shown early on so research and costing out could be achieved. That way a person could judge whether or not he had the available resources to complete the project or even start it. Thanks for your great presentations.
Just come across this video and had one thing to note. When you're doing the settings for acceleration and braking, you should really do the tests with the largest sort of item you might work on in the chuck, as this adds a lot of extra loading and so you should never get an overload error. Also, it's worth getting the external resistor, as it will save the VFD.
The L510 230V model doesn't support a braking resistor.
Did the same thing to my LeBlond lathe in 2011 it turned out wonderful.
Great video and I love the information!!
I was thrilled to find this series of Video's on a VFD Conversion, because I'm going to be doing almost the exact same thing to my Chester DB8. Mainly because using the Lathe at slow speeds (and the slowest pulley set up) ...... it blows fuses if you overdo it, which means anything over a 15mm drill with a very tentative feed rate.
I had to buy a bulk order of 6.3amp fuses because it happened so regularly, and I believe this solution albeit a different Voltage and a bigger Motor (UK 240V Single Phase with a 1.5HP TP Motor).
I really do need the High Torque at slow speeds because I do a lot of TIG welding Tube work, and I tend to make all my own flanges hence needing to drill larger numbers rather than having to bore out each one which takes more time.
I've really enjoyed every minute and commend you on superb work (both Spanners and Sparkies) especially as now I know exactly what I'm going to be doing right down to the last washer - Thank you very much.
You're welcome! I'm glad you found it helpful.
Great vid as usual. I thought this function would be good for thread cutting. It would be interesting to see. The acceleration and breaking at much lower speeds, maybe even turning a thread. Thanks again.
Excellent, thanks for sharing!
Very good tuning like it
absolute nice series! even dough my english is very bad, it helped me a lot! thanks! :)
Great Tutorial!
Well I know what VFD I'm getting now. Fantastic tutorial. So in depth. I was hoping the breaking would have been a little better but I would be able to live with it. Do have plans to add a tach to the spindle in the future?
I have the same VFD running a 1hp Marathon Globetrotter 1750rpm motor, but on a much smaller machine (Grizzly G4015Z 3-in-1) and i run 1 second acceleration and .5 second deceleration times. Obviously I have less rotating mass and thus less inertia, so it doesn't cause me any issues. I tried .2 second deceleration, but it was a bit rough on the machine (audible belt slippage is never a good thing). I do run .2 second deceleration when threading, and use forward/reverse jog buttons to power the machine. I never touch the half nut and spin the lathe backward to retract the carriage. Very handy!
Just brilliant
as i said in another video, great series of videos. i am in the middle of the same process for my 1946 wood lathe that currently has a 12 speed belt drive. It's speed range is around 600- 2500 rpm. One thing you could clarify is how to program the vfd for the remote controls. you stated early on, that your vfd was already setup for the forward/off/reverse switch and the speed pot. the f/s/r switch requires parameter 00-02 to be set to 1. then parameter 03-00 set to 0 and parameter 03-01 set to 1. i haven't got to the speed pot yet.
if i missed your description of this, i apologize! all of the above parameters on mine were set to 0 which is the factory default. as you suspected, someone has been playing around with yours before, maybe factory testing or a returned unit
Thank you for a thoroughly executed video on an important subject. I would like to see a video for use of an external braking resistor with focus on the necessary parameter settings. Any possibility there?
really interresting videos
So much i lern from you, thanks
Very useful. I’ve programmed a Chinese VFD and if I can get one of those working, this should be nothing. I’m swapping my mill motor from BLDC to 3 PH. This VFD was in a list of fairly inexpensive but good for my application.
Very good and helpfull. Thanks. Could you do VFD in lifts too?
A couple of items that may or may not apply to your location and set up James. There's a big difference between my 3 hp Bridgeport clone and your lathe and it was unclear in the video what belt position you had your lathe on. With my step pulley mill in the top spindle speed position the VFD faults out even at 60 Hz at anything less than a 4 second ramp up time. Any belt position below the top one does work fine with a 4 second setting. My guess is there's a fair amount of internal drag to overcome. Also depending on your location and winter shop temperatures there's quite a difference between a warm machine in the summer and even 60 degree shop temperatures in the winter. I ended up programing mine for a 6 second ramp up time so it works fine all year. It's possible there's some parameters I should go back and check after watching this video. But you might find some further fine tuning may be needed. You did a great job on this and if it works half as well as it appears to it should be a large improvement over the stock motor and speed control. It would be interesting to see how much torque you have available at the low rpm needed for anything around the lathes maximum diameter.
Good points to consider. Let me see if I can address them.
The lathe has six belt positions, for 150, 300 and 540? RPM on the back gear (belt), and 720, 1200 and 2400 RPM direct. I have the belt in the 1200 RPM position. This gives me quick access to everything from 120 RPM (6Hz) up to 2400 RPM (120Hz) with the flick of the knob. I've done some turning since finishing this video, and it's been working very well. Being able to tweak the speed while it's in the cut to get the chips to break the way I want is really game-changing.
It does get cold here in the winter, but the lathe castings never get below about 40F (5C) in the shop. At that temperature, the lathe came up to speed easily at 1200 RPM, but struggled a bit on the first start of the morning at 2400. However, since I'm always in the 1200 RPM belt position now, I should have roughly double the torque most of the way up to 2400. It certainly gets there faster now than it ever did with the stock motor and the 2400 RPM belt position.
Low RPMs are a different matter. For anything under 1200 RPM, while the vector drive maintains significant torque all the way down to 6Hz, it can never compare to the added torque of the belt reduction. So far, I've dropped it to 6Hz (120 RPM) to gently scrape out large chamfers with high-speed steel tools and to tap up to 1/4-28, both in mild steel. Neither of these requires much torque, and being able to flick the knob to access the slow speed has been really useful.
The worst-case scenario for torque will be, as you suggest, a large-diameter steel workpiece running slowly. For carbide in steel, this would be around 8" diameter at around 400 RPM. I've never turned anything like that, but if I do, I can always swap out the belts.
Thanks for the additional information. My current lathe is a bit different with only a high and low speed belt position. It's variable speed single ph with no VFD (yet) Low speed belt position and about as low as I can go on the variable gives roughly 50-900 rpm and 900-2400 in the high position. But there's not all that much torque at the bottom speed. Certainly not as much as I'd like at it's maximum swing of 11". Even with a 2 hp vector drive I very much suspect there still won't be enough. As you say for good bottom end torque then some type of mechanical torque multiplier is needed. So it's either build some type of jack shaft arrangement or try and somehow shoehorn in the back gear set up the machine should have been built with anyway. The step pulley, back gear plus VFD on my mill works very well and gives me roughly 30 - 4500 rpm with ample torque within normal cutting conditions.
Great Video, you real should CNC that lathe, I am thinking about doing mine so you could use manual mode if needed
I've thought about that quite a bit. The one thing that CNC would really add to the lathe would be the ability to turn long tapers without a taper attachment or fiddly setups.
I did the CNC conversion on my mill, and I'm very happy with it, but I really miss being able to turn the dials. With ballscrews on the mill, pressure on the axes will easily back-drive the non-energized motors, so I think operating it manually would be pretty tricky.
Where did you learn everything you know about machining? I wish I knew half what you do, or even where to start! Your videos are an amazing resource, thank you so much!
I have spent a lifetime reading and learning from others. TH-cam is a great resource, and I have access to machinists and engineers at work. I'm constantly taking on projects that are just beyond my grasp and learning what I need to know to complete them.
Thank you
You're welcome.
Thank you James. I’ve just re-watched the entire series, and I find this addendum to be particularly helpful!
There’s a topic that might be useful to viewers, and perhaps you can comment. Recalling that hitting your e-stop button kills line power to the contactor, and therefore cuts power to the VFD, what happens in a real deceleration after the e-stop is hit? Does the VFD still absorb energy, aiding the spool-down, without line power? Or, does the machine simply coast down?
Also, in the years since this series, have you by chance added a braking resistor?
Be well!
If you kill power, the load coasts. This VFD model does not support a braking resistor, unfortunately.
Hello James, Is there a way to display the rpm's on the L510?
Hi, the braking transistor and a braking resistor will only develop a slowing down circulating current whist the magnetic field within the motor exists. When you remove the power from a motor the magnetic field begins to reduce, in accordance with the time constant of the motor. Small motors have time constants in the order of milliseconds large motor may reach a second. So once the magnetic field has collapsed there will be no slowing down torque. dc can be applied across the motor which can provide some torque but it is only proportional (slightly) to speed and needs to be removed once stopped. Similarly reversing the 3 phase supply will generate negative torque but this has to be carefully controlled as this has been known to break coupling bolts on large machines. Enjoy turning
Do you worry about premature bearing failure at the much higher rpms that you can achieve now?
Great video series!
The motor is running at double the rated speed, but I'm not worried because I believe (without evidence) that they use the same bearings in the 1800RPM and 3600RPM motors. The spindle of the lathe isn't actually running any faster than stock. Stock, in the fastest belt configuration, the lathe runs at 2400RPM. I have the belt in the 1200RPM position, so at 120HZ, it's turning at the same 2400. Honestly, I'd be nervous to run it much faster. Maybe with a collet chuck and small workpiece something like 3600RPM might be reasonable, but with a bit import chuck spinning, that seems awfully fast.
James, can you please provide what you have for 01-12, 01-13, 01-14, and 01-15? I have the same lathe/vfd, however mine seems to RPM hunt a lot.
How do you see the other modes. I'm in the process of installing this actual drive into my drill press. I can only get programming mode and hz, no volts, no amps. Cannot even figure out how to get it to reverse from the keypad. I can make it run forward or reverse using the S1 and S2 switches
I have all the parts ready to go but cannot find a source for the 9+1 VFD cable.
James What incoming / single or 3 phase voltage are you connected to?
hello clough, i've learned a lot in your videos great work! you also inspired me to put a vfd on my lathe with speed control, i just have one question, given the ability to run the lathe as slow as you want, to the point of you can use it as a welding rotator for tubes, is it safe to weld on the lathe while it is running??? will processes like tig, stick, mig welding hurt the vfd?? thanks a lot
Welding on a lathe is generally a bad idea. Electronics like a VFD can be damaged, but if the weld current goes through the spindle bearings it will destroy them.
v good
Please i need your help 🙏🙏 i have inverter and 3 fase motor in my lathe but i had problem in low HERZT . MOTOR START TO BE HOT AFTER I CHANGED PULLEY LIKE YOURS FOR HAVE MOR TORQUE.....
Great series of videos. One question I have, I read a while ago when I was looking for a 3ph RAS, that when running a motor off of a VFD you should derate the motor to approx. 2/3 of its max HP and that the only way to get close to running a 3ph motor off of single phase at the rated HP is to use a rotary phase converter. Has that changed with new VFD's?
That's news to me. I think a static phase converter has to be derated, but I'm not aware of limitations like that with VFDs. VFDs generate electrical noise and can damage motor windings if they're not rated for inverter duty, but they can also soft start the motor and vary its speed.
@@Clough42 Wow, thanks for writing back so quickly. On a video this old, I was not expecting that. Anyway, I had read that a VFD is not that different from a static phase converter in that you needed to de-rate the motor. I don't know the facts, which is why I am asking since you are more up on this than I. While I am not electronically or electrically inclined, I recall that when the discussion came up at work about wanting to retrofit VFD's to our large air handling units (100 - 200 hp motors), the motors were not VFD rated. After some looking into by our Engineering department, it was determined that motors made from the '90's on are fine with VFD's, regardless of whether they were rated for VFD usage or not. Come to think of it, I think it might have applied to high efficiency motors produced from the '90's on (?), which is what we had by then, and not the "normal" efficiency motors, but this is going back to when I started at my current job about 16 years ago, so I may be mis-remembering things. I know you're thinking that motors from the '90's should probably all be replaced by now, not exactly, motors in that size range get re-built (new bearings, not sure what else may be replaced) and re-wound (when needed) and not fully replaced until they can no longer be repaired, economically.
@@paulprobusjr.7597 Those are big motors. The largest VFD I've ever used is 3HP. I've met a lot of people with vast experience who believe all sorts of things--and probably for good reasons--but I would look to the VFD and motor manuals or consult with the supplier. Most industrial supply houses can answer technical questions about their products.
I think that I would be happy with a 2.5 second start and a 4 or 5 second stop, thereby not encouraging the vfd from destroying itself. I bet the first component to blow will be the voltage transistor running the ramp down time. You had better find out where it is and see if it's replaceable lol
I run half a second stop with the same VFD, no issues. 4-5 seconds isnt fun when threading. I actually cut stop time to .2 seconds when threading and use the jog buttons (added to my remote mount control panel) to power the lathe. I never touch the half-nut and simply spin the lathe in reverse to reset the carriage. Very handy and saves a ton of time.
Can you set safety limits, where the control will ignore those time settings in favor of not frying itself trying to accelerate / decelerate a very heavy load? For example, if you chucked up a 20 pound block would it still try to stop it when the bus voltage hits the 'what the hell are you doing' level?
I'm a big fan of machinery that won't let you destroy it even when you ask it nicely.
The VFD comes set with safety limits that do what you suggest. If you try to ramp it up faster than it can handle, the magnetic field in the motor will slip or the drive will detect an over-current situation and shut down. When decelerating, the VFD monitors the voltage on the DC bus and shuts down automatically when it reaches a preset threshold. When this happens, it essentially disconnects from the load and lets it coast to a stop on its own, just due to friction. For a manual lathe, this is fine. For other applications, like a heavily-loaded downhill stretch of conveyor belt, cutting it loose might get pretty ugly, but then you wouldn't be using a $150 VFD for that, either.
The trigger thresholds are configurable (I played with some of them in the video) but I don't think you can turn them off completely.
I'm very curious what the motor and VFD cost 5 years ago when you originally did this conversion compared to now. The price for the vfd at amazon is just insane, and I found it much cheaper elsewhere. The equivalent motor (different brand) at EMW is about 315 including shipping, and the vfd I got for 225, but seems like it could be had for ~200
What is the suggested rating for the braking resister?
Many place to buy on line.
Thanks
The VFD I'm using doesn't use a braking resistor. I think the 460V models can, but I don't have one.
Does adding another braking resistor help with the braking time and voltage? With mine there are different resistors to assist in the braking.
Yes. An external braking resistor does the job.
I'm confused about overclocking the motor, did the motor tag say you can only go over to 1.15 it's rated capacity is that not 15% (60hz + 15%) ? when you overclock it to 120hrz is that not 100% over and not the 15% on the tag. If I'm wrong please explain?
i think that's 15% above its rated power (so say it's a 1 kW motor; you'd be demanding 1.15 kW)
Thanks for the great info James. This and your other vfd programming video are the best and most comprehensive i've seen. Certainly helps that you're demonstrating practical scenarios along with great explanations. I actually have the Grizzly G0752 which, as i'm sure you know, is the cousin to your lathe and has a VFD pre-installed by Grizzly. One thing I don't love about the Grizzly implementation is the fan they've included to cool the motor is incredibly loud and is always on, when the lathe is in the 'On' state. Meaning the VFD is on and I can now turn the motor on forward or reverse... Here's a clip of the behavior/volume. th-cam.com/video/4Eksans0E5Y/w-d-xo.html I've been thinking of seeing if I can programming the VFD to at least not come on until the motor is spinning. It's just very distracting otherwise and I end up turning the unit off just so I don't have to listen to it. But then I have to wait a good 3-4 seconds after turning on the VFD before I can engage the motor.
Paul Morley you can put a thermal switch, normally open, on the IGBT heatsink and wire it inline with the fan positive. Get a unit that closes at the desired temperature, which will turn the fan on. The right temp might be something like20 degrees over room temperature in your shop.
Hi
Where to configure the VFD starting frequency? Its current starting frequency is 50. I want to change it to 20 Hz. Please advise
Praveen Kumar depending of what vfd you are using.
I know this is older but I'm getting ready to add the same setup to my G0602 and was wondering does this vfd have a more to read rpm instead of hertz or do you need to add some type of tachometer thanks for any help 👍👍👍
* mode to read rpm
Most VFDs have a way to configure a ratio so it can display RPM. I didn't bother because I was planning to include a tachometer in the ELS.
James
Would things be better if you had gotten a 2hp rated VFD as to braking?
John
I don't think so. The real issue on this unit is the lack of support for an external braking resistor.
The setting for the braking transistor cut in might only be for the braking resistor, since you don't have one that might be why it didn't seem to have any effect.
This VFD model has no connection for an external braking resistor. The braking transistor just dissipates the energy into it's own heat sink, so it is pretty limited. Higher voltage models have the external resistor connection.
I installed the E510 TECO inverter on the wood lathe. Watched the whole series, I think. After hitting the stop button, is there a way to shut the VFD down when you're done for the day?
I have mine set up with a contactor. When I hit the E-STOP, it disconnects input power.
@@Clough42 Thank you
What if you put a massive chunk or bar in the chuck? It seems like you calibrated the braking time and ramp up time for a very light load. So is there any room for braking a heavy piece under 4 seconds or will it spike in voltage and cut off since voltage goes over 380? Anyways really good videos. I remember from an earlier video that you changed the PWM setting from 2 phase to 3 phase and got rid of the whining sound, is that the way to go in your opinion? The reason for asking is that I will face this vfd tuning soon when setting up my zetterlund vf600 with a bigger motor and an teco e510 vfd.
If I put something big in the chuck and run into trouble, I'll adjust it. I'd like to have a brake someday, but I didn't realize this VFD didn't support it when I bought it.
@@Clough42 alright. I had a mechanical brake on my storebro gk195 and that felt nice. If something bad happens. But how come it doesnt work with a vfd?
Hi James- thanks again for creating this series- it has been a tremendous help for my G0602 conversion. I ended up using almost all the parts you recommended and i did the inital programming tonight - what a difference! I have a couple question(s)-
* Any issues at 120hz? Dare go higher? I agree with your philosophy that the chassis likely is the same on the 3600RPM version - it would be nice to stretch the legs of the VFD (within reason of course). Honestly i'm more worried about the spindle bearings
* Have you experimented with any settings to help optimize low end torque? During a few tests tonight, i was able to grab the motor pully at 6hz and stop rotation -but- i don't have the belts/mechanical advantage setup yet either
* How does it cut? I suppose i'll know soon enough, but i'm also interested to hear your thoughts. I'm really interested to see how it parts. I've shattered many HSS parting tools and wrecked an equal number workpieces on the slowest OEM setting when i wanted to go slower. It may be the G0602 isn't rigid enough though too-
I can't thank you enough for putting together this series - well done - this is top notch content and its too bad there aren't more channels like yours on youtube - well done!
I have used the lathe on several projects since the conversion and I am very happy. I've done some parting, tapping, drilling and wide chamfers at 6hz with no issues. Yes, the torque is low and it's possible to stop the spindle, but in practice, it hasn't been a problem. I still need to try single-point threading. If torque becomes an issue for a particular job, I can change the belts. Being able to go from 120RPM to 2400RPM with the flick of the knob has been wonderful.
At the high end, 2400RPM is already pretty fast. I could see 3500RPM someday with a collet chuck, but with a three- or four-jaw, that's a lot of energy, regardless of whether the bearings could handle it.
Parting is all about rigidity, speed and lubrication. I have had pretty good results parting in aluminum and steel, but you have to be careful. Keeping a brush with cutting fluid (A9) in the groove, keeping the speed up and keeping the parting tool engaged and making a chip works pretty well in aluminum. The same goes for steel, but at lower speeds. Going too slowly can make the tool grab just as easily as going too fast can make it ring. In general, I prefer parting with the bandsaw if I can. I've even taken the chuck off the lathe and clamped it in the bandsaw with the workpiece still in it to cut it off. Parting in an eighth of an inch, bandsawing the rest and then facing often works well.
Then again, parting is tricky anyway. I've blown up parting blades and even stopped the motor cold on a Hardinge HLV-H before, so there's that.
Clough42 great minds think alike - my more recent go to parting method is a Milwaukee portable band saw -haha - good point on Chuck speed-energy too.
So what happens if your running the lathe at your full speed and you have to hit that estop? Will it damage the vfd?
It shouldn't. I've done it several times with no ill effects. Worst-case, the back-EMF from the motor would power the drive until it stops or shuts down due to over-voltage.
There are a couple of issues accelerating a spindle to quick.
1~ the bearings in the spindle can skip/chatter not good as it will stuff them up.
2~ Holding delicate/heavy parts can be troublesome. As it will not have enough clamp force to accelerate the part. This normally shows as run out.
You can overcome that by fitting a 5C collet chuck that will give minimal inertia.....no worry about spinning a scroll and loosening the jaws.
teco vfd s310+
vfd input voltage 380v,
increase input voltage 390v
parameters set push but error signal
Warning to vintage screw on chucks, fast braking can unscrew your chuck. Wear a catcher's mitt.
I hope people who do this only have D type chucks.
The G0602 has a threaded spindle nose, but also has locks to prevent the chuck from unscrewing.
Just a thought - considering you now have a brand new, uncalibrated variable speed control: how will yo know what speed your lathe is actually running at at any given moment?
The microcontroller uses the spindle encoder to calculate the speed in real-time. I'm making no assumptions about the spindle speed. In fact, I expect it to vary during the cut.
I just realized this was a comment on one of the VFD videos. I was assuming at the time that I could calculate the speed from the lathe speed chart, the motor plate, and the VFD frequency. In reality, it's running a little faster than that. I suspect the belt ratios are only approximate. The electronic leadscrew I'm building now has a tachometer generated from a spindle encoder, so the speed will be measured precisely.
Thanks for the clarification, I'm working through the backlog now and I kinda forgot about your new ELS... :)
nice tuts...need tuts for the hoist apps.. specially hoist with centrifugal brake on motor tail..which parameter to be set for releasing the brake first..
Do you think the the over voltage on decerlation would cause motor bearing damage pits ?
No. That's a separate issue. Motor bearing pitting is probably just normal bearing damage, or common mode electrical current that should be blocked with a big toroidal choke.
@@Clough42 why not just use a grounding ring to ground the motor shaft to the frame of the motor ?
That would be a good solution, probably best used in combination with a filter. Filter toroids are available for about $20. The grounding rings I've seen cost ten times that.
Hey friend, you was just tuning without any heavy load. I believe with a serious load, all settings you make now will be useless.
What you thing..?
i do have a question... don't you have to worry about the chuck spinning off? At least that is what everyone always seems to mention about threaded chucks. Or did you do something so that you don't have to worry about it anymore?
The chucks that come with the G0602 lathe have locking clamps that should prevent this. I probably still wouldn't run it in reverse under load.
@@Clough42 I am curious do you know a way that you could safely run it in reverse?
As that makes it basically non usable then..
Kjj
I believe you have the wrong idea of what the braking transistor does. The braking transistor is responsible for dumping current into an external braking resistor. The setting you were changing dictates at what DC bus voltage the drive should start to dump energy into the resistor. The low voltage shutoff voltage for the transistor dictates the DC bus voltage where the drive should stop dumping energy into the resistor. This should NEVER be set lower than what the bus voltage tends to sit at, otherwise you’ll just be dumping energy into the resistor all the time. If you add an external braking resistor, you could definitely slow the lathe down much faster.
Additionally I’d recommend testing the ramp rate settings with the largest chuck and stock you ever plan on using.
This particular VFD has no resistor and has no terminals to connect one. The braking energy is very limited because it's dumped through the transistor into the heat sink in this model.
@@Clough42 Actually it seems yours doesn’t even have a braking transistor and they left the setting in the firmware anyway. Here’s a quote from the quick start manual: “Notes:
*1: Models 460V 1 ~ 3 HP ratings have a built-in braking transistor. To use this braking transistor a braking resistor can be connected between P and BR.”
@@mman454 looking at it again, I think you're right. I hadn't noticed the diode in the diagram. This model appears to have only DC injection braking.
@@Clough42 I mean, it will still do 20% braking through the IGBTs that it uses to run the motor. So you aren’t wrong in saying that it is doing some regenerative braking and dumping the energy into the heat sink.
I have been following this series with interest, but here you are loosing me.
Why on gods green earth are it so important to get it going from zero to full power as fast as possible ? I mean, you are not living of it as I understand
What would be much more appropriate was to get it to STOP as fast as possible, I mean I can see it in the news:
"Man have VFD'ed his lathe, it can go from 0 to 120 hz in 1.2 seconds, unfortunately he had an accident, hit the emergency switch, and we predict that the lathe stops some time this year."
Wouldn't it be more prudent to get the thing to stop right here and now and maybe use 4 seconds to spin up ?
Yup. I also have it tuned to stop as fast as possible, but this VFD doesn't have a braking resistor terminal, so braking capacity is very limited.