RPM Counter

[Emiliano Achaval]

Today I installed my new WEG VFD. Bought it form Rod Caddaye, owner of Omega Lathes. The unit is very well made, a big improvement over the original Eaton VFD that was added by Stubby USA. I always disliked the idea of the VFD out in the open, where dust, wood chips, spiders and here in Hawaii, Geckos can lay eggs inside. The new unit it's in a nice closed little cabinet, with a computer fan and filters for fresh air. Only problem is, I do look at my RPM when I turn boxes with hand chased threads, specially if I'm teaching. Also, during demos, there is always a beginner asking me at what speed I'm turning. The RPM readout is inside the little cabinet, not very convenient. I have heard of other ways of getting the RPM's... I could do some Google research, but I like to see what other woodturners have done. Thanks in advance. Aloha

 

[Dan Bevilacqua]

Emiliano, speaking of "teaching" and "demos", congratulations on being a demonstrator at the upcoming 2019 Symposium.

 

[Martin Groneng]

Emiliano will do anything to get out of Hawaii for a break and us freezing our butts of in Canada will do anything to get to Hawaii in the winter.

I've been to Maui twice and next time, I plan to terrorise Emiliano and bring him some Manitoba (red and spalted) Maple !!!

 

[Doug Rasmussen]

Presumably you have an accessible potentiometer knob to vary the speed. You could put marks around that dial to indicate RPM. You don't say exactly,. but does the readout in the box show actual spindle RPM or motor frequency in HZ?

If it shows HZ (which most VFD's do) you'll have to do calculations based 60 HZ being the motor's base RPM taking into consideration ratios in any belt drives. If it shows actual spindle speed you could extend the readout wiring and mount the display where it's readily visible. If you're at all comfortable with electronics you might find a kit to display RPM of rotating devices.

Amazon has a number of small hand held digital tachometers in the $30 range.

 

[Bill Boehme]

The RPM's that the inverter displays is the motor speed so you won't see the spindle speed unless the motor to spindle pulley ratio happens to be exactly 1:1.

Doug, many inverters allow all sorts of display options such as displaying motor speed or even using a multiplier to show spindle speed without needing to calculate these values. On some inverters (Baldor) the display can be unplugged and placed remotely by using ribbon cable

There various kinds of sensors that you can buy that will give you a direct readout of the spindle speed and they aren't very expensive.

 

[odie]

We need to see photos, Emiliano!

-----odie-----

 

[Dwight R Rutherford]

There are quite a few hand held units on Amazon for under $20.

 

[Emiliano Achaval]

Emiliano, speaking of "teaching" and "demos", congratulations on being a demonstrator at the upcoming 2019 Symposium.

Thank you Dan! Very excited about it, and quite an honor!

 

[Emiliano Achaval]

The RPM's that the inverter displays is the motor speed so you won't see the spindle speed unless the motor to spindle pulley ratio happens to be exactly 1:1.

Doug, many inverters allow all sorts of display options such as displaying motor speed or even using a multiplier to show spindle speed without needing to calculate these values. On some inverters (Baldor) the display can be unplugged and placed remotely by using ribbon cable

There various kinds of sensors that you can buy that will give you a direct readout of the spindle speed and they aren't very expensive.

I will ask our resident Electrical Engineer to see if we can add a rpm readout. Stay tuned!

 

[Emiliano Achaval]

We need to see photos, Emiliano!

-----odie-----

I'll take some today!

 

[Emiliano Achaval]

Emiliano will do anything to get out of Hawaii for a break and us freezing our butts of in Canada will do anything to get to Hawaii in the winter.

I've been to Maui twice and next time, I plan to terrorise Emiliano and bring him some Manitoba (red and spalted) Maple !!!

Make sure you stop by to see me!

 

[JeffSmith]

I will ask our resident Electrical Engineer to see if we can add a rpm readout. Stay tuned!

Emeliano - I put one on my Robust from pieces sourced online - total was less than $35. That said, after about three months I found I didn’t need any more than the speed chart that came with the lathe and took the whole thing off. I’d recommend getting one of the cheap hand held versions and calibrating your speed dial. Easier, just as accurate and not distracting...

 

[RichColvin]

Emiliano,

I’d look at an Arduino. There are great DIY techniques that you can find via Google. One is https://duino4projects.com/arduino-rpm-counter-tachometer-code/.

This is commonly done for drill / pillar presses.

Rich

 

[Emiliano Achaval]

Today I installed my new WEG VFD. Bought it form Rod Caddaye, owner of Omega Lathes. The unit is very well made, a big improvement over the original Eaton VFD that was added by Stubby USA. I always disliked the idea of the VFD out in the open, where dust, wood chips, spiders and here in Hawaii, Geckos can lay eggs inside. The new unit it's in a nice closed little cabinet, with a computer fan and filters for fresh air. Only problem is, I do look at my RPM when I turn boxes with hand chased threads, specially if I'm teaching. Also, during demos, there is always a beginner asking me at what speed I'm turning. The RPM readout is inside the little cabinet, not very convenient. I have heard of other ways of getting the RPM's... I could do some Google research, but I like to see what other woodturners have done. Thanks in advance. Aloha

Got some pictures today. Sorry, I was too lazy to open the cover, it has 4 screws. I will have to open it a few times a month to clean it. I dont expect much dust, if any, the computer fan draws air thru a filter.... Lathe run like a Rolls Royce today! Very happy with the VFD programming, done by Rod Caddaye, he's done a few, LOL.

 

[Emiliano Achaval]

Today I installed my new WEG VFD. Bought it form Rod Caddaye, owner of Omega Lathes. The unit is very well made, a big improvement over the original Eaton VFD that was added by Stubby USA. I always disliked the idea of the VFD out in the open, where dust, wood chips, spiders and here in Hawaii, Geckos can lay eggs inside. The new unit it's in a nice closed little cabinet, with a computer fan and filters for fresh air. Only problem is, I do look at my RPM when I turn boxes with hand chased threads, specially if I'm teaching. Also, during demos, there is always a beginner asking me at what speed I'm turning. The RPM readout is inside the little cabinet, not very convenient. I have heard of other ways of getting the RPM's... I could do some Google research, but I like to see what other woodturners have done. Thanks in advance. Aloha

I found this web site: http://www.mkctools.com/tachulator.htm. has anybody use one of these?

 

[Emiliano Achaval]

Today I installed my new WEG VFD. Bought it form Rod Caddaye, owner of Omega Lathes. The unit is very well made, a big improvement over the original Eaton VFD that was added by Stubby USA. I always disliked the idea of the VFD out in the open, where dust, wood chips, spiders and here in Hawaii, Geckos can lay eggs inside. The new unit it's in a nice closed little cabinet, with a computer fan and filters for fresh air. Only problem is, I do look at my RPM when I turn boxes with hand chased threads, specially if I'm teaching. Also, during demos, there is always a beginner asking me at what speed I'm turning. The RPM readout is inside the little cabinet, not very convenient. I have heard of other ways of getting the RPM's... I could do some Google research, but I like to see what other woodturners have done. Thanks in advance. Aloha

Forgot to mention that the new VFD goes from 0 to whatever. Before I could not make it go really slow, like 2 rpm...

 

[Mike Johnson]

Emiliano,
With an enclosed VFD with cooling fans you will want to clean or replace the intake fan filters on a yearly basis as needed. You could possibly add a pre-filter over the fan intakes to reduce the amount of fine wood dust that makes it into the inner fan filters that will plug up from fine wood dust. There are several types of fan filters available, some are washable and some are disposable, some you can blow out with compressed air. Using a shop vacuum or compressed shop are hose can be risky in blowing out dust or vacuuming dust from a VFD enclosure as it can introduce static charges inside the VFD that can corrupt memory/program on the circuit boards. Static charges would be less of a problem in your island environment compared to someone else in a dry environment. Technicians that work on solid state equipment will use vacuums supplied with static grounding systems built into the hose and tools to prevent static discharges, they will also use the small cans of compressed air to remove dust from the enclosure and circuit boards. Anyone attempting to use shop air for this purpose needs to reduce the air pressure and add a static grounding discharge conductor to the end of the air hose tool to mitigate any static charges produced by the air flowing through the polymer hoses. The other issue with using shop air are oil and water contaminates that can be introduced on to your VFD circuit boards. Anyone working inside the VFD enclosure should also be wearing a static grounding device if they will be working close to the circuit boards to prevent potential static discharges.

The other concern with using VFD's in a shop area is temperature, if your shop area maintains a stable ambient temperature that is comfortable to work in you should not have a problem. If your work space has a higher ambient temperature that gets warm this can be problematic for some VFD's. Most VFD's usually require heat sinks or forced air circulation to remove heat from the electronics to operate correctly. Too much heat and the VFD can suffer faults and failures from over-heating. You can use an external fan blowing on the enclosure to help pull heat from the enclosure if needed. Vortex coolers can be used with compressed air systems to provide cooling to a VFD enclosure if needed. Small air conditioning systems are also available for VFD enclosures that are operated in higher ambient air temperature environments when needed. On some installations we have used process air to provide a pressurized atmosphere inside a secondary cabinet that the VFD was installed into. The enclosure needs to be of adequate size to dissipate the heat gain from the VFD or utilize a heat sink, air exchange, air conditioning to maintain a proper temperature inside the secondary enclosure. Providing a stable cool environment for your VFD and it will run for years, expose the VFD to higher ambient temperatures and it will fail from higher operating temperatures on the circuit boards and components. Dust and dirt built up on circuit boards and components will also limit the ability of the VFD to cool properly. Your work shop environment will usually dictate the best solution for having a VFD in the area, a yearly cleaning program for the VFD or installing the VFD in a secondary enclosure to mitigate the dust exposure, or maintaining dust collection systems in your shop area that provide adequate air quality to operate your VFD equipment. The other option is to expose the VFD to all of these environmental issues and run the VFD until it fails, depending on the cost this can sometimes be the simplest solution.

 

[Don Wattenhofer]

Today I installed my new WEG VFD. Bought it form Rod Caddaye, owner of Omega Lathes. The unit is very well made, a big improvement over the original Eaton VFD that was added by Stubby USA. I always disliked the idea of the VFD out in the open, where dust, wood chips, spiders and here in Hawaii, Geckos can lay eggs inside. The new unit it's in a nice closed little cabinet, with a computer fan and filters for fresh air. Only problem is, I do look at my RPM when I turn boxes with hand chased threads, specially if I'm teaching. Also, during demos, there is always a beginner asking me at what speed I'm turning. The RPM readout is inside the little cabinet, not very convenient. I have heard of other ways of getting the RPM's... I could do some Google research, but I like to see what other woodturners have done. Thanks in advance. Aloha

I have been using VFDs since the early 1990s before the Manufacturers were supplying them. The first one that I installed on a Delta lathe was one I found in a surplus store that had never been used but since it was an early unit that apparently had it's own bugs it didn't last for more than about 4 years. The unit was housed in a steel cabinet that measured about 18" x 24" x 8".
In my current shop I have 6 different machines (that includes 2 wood lathes and 1 metal lathe) that I installed the VFD to either convert single phase power to 3 phase with the added advantage of variable speed and accsel/dsccel. The VFDs that I now have, none of which cost more than $350.00, are mature technology in open housings and none have failed in 20 years time even though they get covered in dust and shavings.

The last one I installed is on a Grizzly lathe that came with a stepper motor and controller (rated 2 HP at 3600 RPM) because the controller fried and it didn't have enough torque to use the bowl saver. The conversion required converting to a 1725 RPM 3 ph induction motor along with the VFD so now I don't have a torque problem. The controls that came with lathe I was able to reuse (the E-Stop became the power switch, the forward / reverse selector switch did the same with the VFD, the speed potentiometer connected to the VFD and the tach didn't require and changes because it has a sensor on the spindle shaft. Note I have a background in controls engineering and I first had exposure to VFDs in about 1980.

 

[Zach LaPerriere]

What I really want is an RPM counter that reads aloud to me in the voice of Count von Count from Sesame Street. Ahh-hah-hah-hah.

 

[Don Wattenhofer]

If I didn't already have a tachometer mounted on the lathe I would not worry about it since the only time I need to know the RPM that works in a given situation is during a demo when someone asks "how fast is that".

 

[R Henrickson]

If I didn't already have a tachometer mounted on the lathe I would not worry about it since the only time I need to know the RPM that works in a given situation is during a demo when someone asks "how fast is that".

Exactly. My current lathe doesn't have an RPM readout. I don't miss it -- I've found I can judge speed quite accurately by eye, even where a specific speed is desirable (e.g., texturing). I don't do demos on my home lathe. Almost always the lathes I use in public demos have readouts, if someone asks.

 

[Adam Cottrill]

I purchased a digital tachometer like this one from ebay: https://www.ebay.ca/itm/1PC-4-Digit...itch-Sensor-NPN-/222475499225?var=&hash=item0, attached a rare earth magnet to the spindle and mounted the hall sensor inside the headstock so that it could read pick up the magnet on each revolution. The unit is powered off of the VFD so it powers up and turns off with the lathe just like a factory one would. If I remember correctly, the unit came with no documentation at all, but this post helped me figure out what each wire was for: https://forum.canadianwoodworking.com/forum/workshop-talk/shop-related-discussions/shop-electrical/1149410-digital-tachometer-wiring-question.

My bare bones lathe had a name plate over the opening that higher end models have tachometers and contols mounted in. I removed the factory plate that covers the hole and replaced it with a small piece of steel cut to the same size, cut a hole for the tachometer readout and painted to match the rest of the lathe. I doubt anyone would ever now that it was an after-market addition.

The readout has a little bit of lag, but stabilizes after a few seconds. I'm not sure if factory tacometers are like that, or just those that cost less than $10. Either way, it has served me well.

 

[Don C Davis]

I guess I am one of the few that feels an accurate digital readout is a big positive--I do lots of drilling on the lathe and knowing the RPM's is valuable to me--and in my experience NOBODY is really good at accurately judging RPM's, in fact when I had several long experienced turners judge the RPM's a lathe was running that had a known accurate RPM readout, it was incredible what a gap there was in guesses--from way high to way low--it also just pisses me off that major mfgs. don't all include them, since the parts to do one would cost them under $10 At any rate I believe that unit you provided a link to is more than sufficient to give you true spindle RPM's Emiliano--congrats on being a symposium demonstrator, you sure deserve to be one.

Good luck on your efforts!

 

[Emiliano Achaval]

Emiliano,
With an enclosed VFD with cooling fans you will want to clean or replace the intake fan filters on a yearly basis as needed. You could possibly add a pre-filter over the fan intakes to reduce the amount of fine wood dust that makes it into the inner fan filters that will plug up from fine wood dust. There are several types of fan filters available, some are washable and some are disposable, some you can blow out with compressed air. Using a shop vacuum or compressed shop are hose can be risky in blowing out dust or vacuuming dust from a VFD enclosure as it can introduce static charges inside the VFD that can corrupt memory/program on the circuit boards. Static charges would be less of a problem in your island environment compared to someone else in a dry environment. Technicians that work on solid state equipment will use vacuums supplied with static grounding systems built into the hose and tools to prevent static discharges, they will also use the small cans of compressed air to remove dust from the enclosure and circuit boards. Anyone attempting to use shop air for this purpose needs to reduce the air pressure and add a static grounding discharge conductor to the end of the air hose tool to mitigate any static charges produced by the air flowing through the polymer hoses. The other issue with using shop air are oil and water contaminates that can be introduced on to your VFD circuit boards. Anyone working inside the VFD enclosure should also be wearing a static grounding device if they will be working close to the circuit boards to prevent potential static discharges.

The other concern with using VFD's in a shop area is temperature, if your shop area maintains a stable ambient temperature that is comfortable to work in you should not have a problem. If your work space has a higher ambient temperature that gets warm this can be problematic for some VFD's. Most VFD's usually require heat sinks or forced air circulation to remove heat from the electronics to operate correctly. Too much heat and the VFD can suffer faults and failures from over-heating. You can use an external fan blowing on the enclosure to help pull heat from the enclosure if needed. Vortex coolers can be used with compressed air systems to provide cooling to a VFD enclosure if needed. Small air conditioning systems are also available for VFD enclosures that are operated in higher ambient air temperature environments when needed. On some installations we have used process air to provide a pressurized atmosphere inside a secondary cabinet that the VFD was installed into. The enclosure needs to be of adequate size to dissipate the heat gain from the VFD or utilize a heat sink, air exchange, air conditioning to maintain a proper temperature inside the secondary enclosure. Providing a stable cool environment for your VFD and it will run for years, expose the VFD to higher ambient temperatures and it will fail from higher operating temperatures on the circuit boards and components. Dust and dirt built up on circuit boards and components will also limit the ability of the VFD to cool properly. Your work shop environment will usually dictate the best solution for having a VFD in the area, a yearly cleaning program for the VFD or installing the VFD in a secondary enclosure to mitigate the dust exposure, or maintaining dust collection systems in your shop area that provide adequate air quality to operate your VFD equipment. The other option is to expose the VFD to all of these environmental issues and run the VFD until it fails, depending on the cost this can sometimes be the simplest solution.

I paid US$ 1300/ I have to make this one last at least 5 years, LOL. Thanks for all the great advice!