VFD'ing my lathe (Takisawa TSL 1000)

umnik

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VFD'ing my lathe (Takisawa TSL 1000)

I've recently got new (to me) lathe which is 3 phase. I do not have 3ph in my possession and need to do something about it to get my lathe running. I decided to go VFD route, to have some advantages of these motor drives. I've got some experience with VFD already, converting my drill press, but it was not complicated system, just variable speed and fwd/rev. Now I want to add some more features in the system for my lathe. I decided to start that thread to discuss whole system, hear advises and suggestions and I think it could be helpful for other folks who want to go VFD route, taking into account how complcated the topic can became.

What I want as I am thinking for now.
1. Variable speed control using external resistor;
2. Instant Fwd/Rev, likely employing built in Lever for that;
3. Quick stop using VFD and external resistor.

What I already have.
1. VFD Invertek ODE-3-320153-1042, 5 HP, 230V 1-Phase In;
2. Braking resistor 100ohm, 1000W

Lathe
two speed motor. 5hp 4 pole high speed and 3hp 6 pole low speed.
lever - Rev/Stop/Fwd which I am thinking to use as external control for VFD.
Has working coolant system, but the motor is 3ph. Likely it's better just replace it with similar single phase variant.

I am planing to get Electrical box/panel top put vfd into it, but still do not know if I should put the rest elctrical stuff into that box or just reuse lathe's current electrical box.

The lathe has (from top to bottom):
* rotary switch LO/HI for motor, which will be obsolete and can be reused for other purposes;
* ON Light indicator;
* ON/OFF rotary switch;
* Coolant ON/OFF rotary switch;

I see that folks here put proximity sensor and joggers, but can not understand what exactly they do what purpose they serve.

Anything else should I consider?

20190925_224629.jpg
 

pontiac428

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Congrats on the Takisawa. I am interested in what people have to say about retrofitting the VFD to a lathe like this (separate motor for coolant, multiple circuits) because that is our best option (3-phase in residential is not). Hopefully, some of the other Taki owners on this site can help answer your questions, I'll be watching for answers!
 

umnik

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Thank you, Pontiac.
For second coolant motor you have to use another VFD. The motor is 1/8 HP and does not require special features like electronic braking and such, so the VFD can be pretty inexpensive, but still you need to put some circuitry to drive the motor. I think it is possible to put it on static phase convertor, but anyway you have to buy one anyway. So economically, I am thinking to bbuy something like that
and call it a day.
There is Takisawa subforum here, but I found that discussion there mostly concentrated on mechanical aspects and not much details on VFD.
 

mksj

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I have worked with a few individuals on installs on Takisawa lathes, it is all a matter of going the VFD route vs. the RPC. Most people end up with an RPC because it is a quick solution. VFD's on the lathe are a bit more complicated as to the degree of functions and areas of safety. Typical practice is to remove all the current control systems and wiring and do a complete install on an older machine like this. The coolant pump is almost never used, most people either remove it or replace it with a single phase 240VAC if they see the need. Rarely, I have used a small dedicated KBAC KBVF-23 0r 24 VFD to run another motor as part of the 3 phase conversion system, these can be picked up for $50-60. If you go with a single phase coolant pump, it should be run through a contactor with a properly sized overload relay. The switch operates a low voltage contactor coil which then operates the high voltage (same as the stock system). This requires a low voltage source such vas as 24VDC or VAC, depending on the rest of the systems.

There are several areas to consider with this lathe, 2 speed motors that are not constant Hp in my experience have not run well off of VFDs for some reason. I would not use the 6P setting, I would wire it for 4P (5 Hp). If it was a constant Hp, then that would be different.

There are a few other considerations/limitations to address.
1. You can have the current lever - Rev/Stop/Fwd control the VFD direction, but there are no safety interlocks to prevent the lathe form starting if the lever is in the wrong position on power up. With the contactors, there is typically a power relay that prevents this from occurring, same thing if you were to have an E-Stop you wouldn't want the machine to restart when the switch was disengaged. The Invertek (P-30 command) and most VFDs do have a Restart prevention setting if there is a run command in effect on power up.

2. Typically you want to take advantage of different braking rates offered by VFDs that have this function, fast stopping in emergency and turning/threading to a stop, longer braking for general turning. This is usually done through a programmed input.

3. The manual foot brake needs to operate several different VFD functions when depressed. 1st is to deactivate the VFD run command, 2nd disengage the power/latching relay to prevent restart when the foot brake is released, 3rd is to issue a free run command to the VFD the disengages the output stage. This allows the braking to be solely controlled by the foot brake, otherwise the VFD will override the foot brake. There must be some interlock to prevent lathe restart on release of the foot brake. Typically these involves cycling the spindle direction through the stop position or a power reset button.

4. Jog button/joystick, many people use this for low speed threading or to jog the chuck forward/back as needed. The frequency is set to a default, typically 6 Hz. It is run through a dedicated JOG input on the VFD, the specifics differ based on the manufacture's VFD.

5. An automated stop system interrupts the run command to the VFD and applies rapid braking, this can be done through a mechanical switch/mechanism, or some form of electronic sensor such as a proximity stop. I use the latter because it has no physical contact and the sensing range is longer then typical plunger type switches. The implementation needs to be designed into a system. The accuracy of repeat stopping position for proximity sensors is better than 0.001". There are high accuracy limit switch (which cost as much as a proximity sensor), but these are limited by travel/stroke of the switch and physical damage.

6. Most likely you will want a tachometer, these can be purchased inexpensively and are easy to install, the do require a 12VDC power source. I typically run a 24VDC power supply (60-75W) and use a small step-down converter for 12VDC components. Alternative is to purchase two small power supplies. I often will make a small tach housing that goes on top of the machine/under a DRO if installed and put the VFD speed pot in the same housing. In this case you also have the option to put the speed pot in one of the switch holes. You could use the L/H switch hole currently used for the motor speed.

One of the concerns I see is with the VFD you choose, there are technically only a few factory VFD that are single phase 5 HP, but the Invertek are significantly limited by the number of programmable inputs (total of 3, two are used for the for/rev) and limited programming functions. I do not see any provisions for different braking/acceleration rates controlled by an input, Jog input, free run (Coast to stop), etc. So you are basically limited to For/Rev and Speed. If that is all you are looking for then it will work, I still do not know how to address the mechanical brake, there may be a parameter to shut down the output in an Alarm mode and program this to input 3. In these situations the VFD I typically use is a Yaskawa CIMR-VUBA0018FAA. Otherwise I use a 3 phase model derated for single phase use, and I recommend a DC choke. Single phase input: https://motorsandcontrol.com/yaskawa-cimr-vuba0018faa-5hp-1-phase-200-240v-input-nema-1-enclosure-variable-frequency-drive/ See example off attached programming parameters.
Three phase input 7.5 Hp VFDs derated for single phase input, recommend use with a 25A DC choke. Examples: Hitachi WJ200 WJ200-055LF, Yaskawa CIMR-VU2A0030FAA, Fuji FRN0030E2S-2GB

There are some simple single latching relay/dual designs that I used many years ago that will drop out on fault and prevent a restart situation, I would need to dig through my files to fins something that you could work off of.
 

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umnik

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mksj,
thank you for the explanation and valuable info, as usual, extremely informative.
Now I realized that VFD I have is not that great from point of programmable inputs. I bought it, because it was only one I could find which is 5hp and 1 phase input. Will try to return it for different drive. I briefly checked documentation for different drives, they specs output voltage and amperage but for input, only voltage. Why is so? I need to know amperage for power line for VFD. Any difference in power line requirement (gouge/amperage) for single and three phase VFDs mentioned?
 

mksj

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The VFD's indicated all run off of 200-240VAC. I recommend the Yaskawa linked above, I purchase my Yaskawa drives from Motors and Controls. I would see if you can return the one you purchased, it is difficult to sort it all out. On the lathe it is a bit more challenging, and also the higher Hp. The VFD manuals spec. the input current of the VFD and recommended fusing, or you can also speak to the distributor as to recommendations. The parameter file provided is what has been used on two other machines using the same Yaskawa VFD 5Hp model. Price wise they are all similar.

There is a bit of a wrinkle if you go with a higher powered 3 phase input VFD and derate it for single phase, the input wiring/fusing still needs rated at the full amperage of the VFD, not what it is powering. A DC choke is often used with derated 3 phase VFDs to decrease the fusing requirement, i.e. the current pulse that charge the capacitors. This also decrease the THD or ripple on the bus. The Fuji manuals gives some further details, but all the manuals are intimidating, I can't tell you how many times I have reread them. You also will get better tech. support if you buy from a US distributor. The Yaskawa 5Hp VFD recommends some pretty large fuses, but it should be able to operate off of a 50A breaker/circuit. I would check with the distributor on this. The derated VFDs technically may need a larger breaker/service, typically it is 125% of the single phase input and conversion from 3 phase to single phase you would multiply the 3 phase current by ~1.7 to give the single phase current. This is outlined well in the Fuji Frenic-Mini manual in Chapter 6.

One option that you can do to simplify the install would be to replace the contactors for the forward/reverse and strip out the high voltage to those contactors/motor connections. Use one of the contactor inputs to turn on the VFD input for the corresponding spindle direction. You need new contactors because there is too much contact resistance with used contactors. The replacement contactor only needs to be matched for coil voltage/type, typically either 24VAC or 120VAC (check the schematic or contactor coil voltage). I replace them with mini-contactors, I can provide you links and info. I am not an electrician, I have only been doing this as a hobby, so I recommend that you get the high voltage/wiring checked out by an electrician to meet local code.

Might review this, it applies to the 1340GT basic VFD install.

You would leave the coolant contactor/overload relay if you plan to use coolant, if you go with a single phase coolant pump the amperage will be a bit higher, there may be enough adjustment on the overload relay or you may need to replace it.
 
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matthewsx

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VFD's are a wonderful advancement for getting 3-phase where it is not, but doing a project like this is a major undertaking as MKSJ points out.

All things being equal I would seriously consider an RPC for this kind of machine. Of course the decision is yours but my experience has been with my Seneca Falls Star lathe which only has one motor and no control circuitry so very easy to convert. And my former Gorton 1-22 MasterMill which had many faulty contactors and a vacuum tube based table feed system. For that one I had planned on re-configuring everything and going to all VFD's but I ran out of time and space when I sold my shop.

An RPC will definitely cost less than converting to VFD's especially since the relays, switches and other components currently installed may not be compatible. You can often find them used and having one will allow you to run other 3-phase stuff you might acquire in the future. Also, if the machine is basically working you will be making chips in days rather than months.

A conversion like this, done right, is going to be pretty close to what you'd need to do if you were going CNC. Your list of wants for the conversion is pretty small compared to the amount of work it will require; honestly if I had this lathe I would just return the VFD and put that money towards an RPC. Even if you end up converting it eventually it will be good to know if everything is working as/is. Plus, VFD's whine. Seriously. Annoying. Whining:(

JMHO,

John
 

umnik

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John,
I considered to get a RPC at some point. I understand advantages of such devices, especially plug and play approach or dealing with multiple 3 phase machines. Thought after some research online I decided against it. I need to significantly oversize RPC in terms of HP ratings, they are big and take extra shop space which is premium for me, but main reason they are not quiet at all (choice between humming (RPC) and whining (VFD) ;-)
I'd go with digital phase converter, like Phase Perfect, but they they are so expensive!
 

matthewsx

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Your machine, your choice.

RPC can live in a shed outside the shop though.
 

Briney Eye

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I “silenced” my VFDs by increasing the carrier frequency. I believe that was 15khz on my Fuji. As far as I could determine the motor couldn’t tell the difference. YMMV.
 

Eddyde

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I run both VFDs and an RPC in my shop. Personally I find the RPC quieter, less annoying. I built The RPC from about $250 parts including a used 7.5 hp. idler motor.

If you do decide to go the RPC route here's a link to my build thread:
 

Winegrower

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I use a static phase converter on my Takisawa TSL-800D. I use the same converter for the Bridgeport and the Kalamazoo horizontal saw. I don’t see that a VFD would add substantial features to any of these machines...they all have worked fine for decades, and have adequate speed control capabilities.

I did add a VFD on my Powermatic wood lathe, because the original Reeves drive is a bit clunky.

I would rather spend my time machining than rewiring...and I’m an Electrical Engineer.
 
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mksj

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Static converters loose 1/3rd to 1/2 the motor Hp depending on the design, in particular with a 2 speed motor. I have also seen a number of reports of surface finish issues with static converters vs. RPC/VFD. On a mill, less of an issue, lathe and surface grinder I would just go with an RPC/VFD. Cost wise, a VFD is a reasonable alternative to an RPC for smaller motors, beyond 3 Hp the costs of a VFD increase significantly. VFD's have many features like speed control, soft start, electronic braking, slow speed jog, etc., but if you do not need these then an RPC is probably a better choice. I have done a few shop system installs where the shop was run off of an RPC, and we installed several 3 phase input VFD's on specific machines that benefited significantly from there additional features. One doe not negate the other, and there is minimal to no derating of the VFD in this arrangement.

Cost wise up to 3 Hp, VFDs are probably more cost effective and simpler to install on machines like mills and surface grinders, but lathes take a little more effort to do it right. As far as VFD whine, depends on the VFD, motor and software/parameters. My mill and lathe (both 3 Hp) with Yaskawa VFDs, the carrier frequency is 12 kHz, I no whine whatsoever. The Yaskawa also has programs for variable switching frequency settings as opposed to fixed. Higher switching frequencies can lead to more motor heating and insulation breakdown, but this is not an issue with newer motors. Old motors should use a lower carrier frequency.

Machines are an investment over time, we spend numerous hours adding accessories and modifying the machine to fit our needs, adding a VFD is no different. The time consuming portion is figuring out the design, materials and getting everything in house. Building the system correctly and understanding the wiring connection the VFD and the programming parameters are a bit of a hurdle, so sharing one's experience helps others to get started. The system build time is trivial in relation to the years of use and benefits if you use the features of a VFD. Investment/cost wise, you can go super cheap these days with a VFD, or invest a bit more and get more features. I have installed numerous VFDs and worked with 100's of people doing VFD installs, I can't recall anybody that would have done otherwise and almost everyone wishes they had done it sooner. Also know many RPC owners that are just as happy, recently I have seen a number of small shops using the AMP RPC's which are plug and play, they were super quiet. Plug the cube into the wall, plug the machines into the cube and you are up and running. There are also other less expensive RPCs that work great.

www.wnysupply.com

Below is an old thread on a G4003G VFD conversion, it is a very simple 3 relay design, and did not take very long to install. If this is something you are interested in, I will update the schematic to include provision for the foot brake, differential braking etc. to the VFD of your using and provide you with a basic parts list. I have previously outlined the suggested VFD enclosure components, etc. in other posts. It is a more expensive proposition at 5 Hp and above, but I think you will be very pleased at the end of the day. Otherwise, buy a static converter as a band-aide to get you started, or add a motor to get you to an RPC and then go from there.
 
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Winegrower

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Mksj, I appreciate your comment about loss of power. I have to say that I have never seen an instance when I thought the lathe was lacking power. However, this lathe is so much more powerful and stable than I have used before, perhaps I am being too conservative. Anyone have any guidelines for what a 3HP 14” lathe ought to be able to do? If so, I’ll give it a try.
 

mksj

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Winegrower, with a 14" lathe and a 3 Hp motor, with a static inverter you might be realizing maybe 2 Hp from the motor. In essence you are running off of 2 out of 3 coils, and you would also expect some imbalance. Heavier machines, may not show as much surface issues due to the momentum of the system/mass of the machine. You also loose torque. Cutting power wise, unless you are pushing really hard, 2 Hp is more than enough and you are not loosing Hp when gearing down. One could do comparisons to see how much of an effect this would have vs. an RPC, can't recall seeing this. But certainly single phase to 3 phase with a VFD, I have seen pretty dramatic differences in surface finish/motor performance. I also recently participated in a few discussions in surface grinder conversions and there was a number comments of poorer surface finish/performance running 3 phase surface grinder with a static converter. They work, some maybe better than others, but an RPC is not much more and more flexible for different machines. Use a low speed RPC motor, more of a faint hum as opposed to a roar. There is some power consumption penalty, but the few I have seen worked very well/quiet (like the AMP cube and a few larger systems). There are additional costs if running a shop with multiple machines and adding a 3 phase sub-panel.

On 2 speed motors things become a bit more complicated as to their performance with static converts and to some degree RPC's. See some threads below. I have also seen this in some home machine shops and other people I have worked with. My take on this is static converter for a 2 speed motor is not a good choice, and even an RPC may not always work. I do feel these days that for a single 3 phase machine, 3 Hp and below, VFD's are a very competitive option if you can keep the control system simple. There is a learning curve, and I was a bit overwhelmed working with my first VFD. After that it gets easier.
 

Winegrower

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Mksj I always appreciate your thoughtful analysis. A net 2 hp with the simple phase converter works fine so far. For my wood lathe, the VFD was an easy add...there are really no electrical controls to worry about, so running everything from the VFD front panel was straightforward. For the Takisawa, with the foot break, direction switch, coolant pump, etc., it just seemed like too much of my remaining life would be squandered. A local friend who surprisingly also has the same TSL-800 uses a RPC. Man, his whole shop seems to fill with the noise, and he had that professionally installed some way. The low noise option would be a huge plus, if they tend to be that noisy.
 

umnik

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Update. On mksj advise I returned my Invertek vfd and bought Yaskawa VFD (like to use Yaskawa for Takisawa ;-)
Yestreday, I, with help of friend, connected the VFD to my lathe and get it running. Get it working.
Now, I need to design whole control system. I like Marks design and will take it as base for my system.
 
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