VFD or Phase-a-matic?

[Rob Clark]

I apologize in advance for the off topic subject.

Is there any benefit in switching from a phase-a-matic phase converter to a VFD?

It seems like the VFD has some programming features that I'm currently unfamiliar with, so I'm unsure if there is a benefit to switching the phase-a-matic out.

All responses are appreciated...maybe even the condescending ones.

[Alex Wetmore]

VFDs give much better control of the motor at custom speeds.  They understand how to shape the waveform to get high torque out of the motor even at very low RPMs.  I have the VFD on my mill setup with a simple control that gives me a 10x range in motor speed (by changing from 9-90hz on the 3 phase side), and with VFD-ready motors you can get an even wider range.

It is also kind of cool flipping the direction switch and watching it slow to a stop, then reverse in the other direction.  That isn't very useful though.

If your current setup meets your needs then there might not be a reason to tinker with it.  VFDs are amazing though, and there isn't any reason to consider anything else.  My lathe has a single phase motor and I've often considered getting a 3 phase and VFD for it.

---

From: frameb...@googlegroups.com <frameb...@googlegroups.com> on behalf of Rob Clark <recl...@gmail.com>
Sent: Wednesday, November 22, 2017 9:22:07 AM
To: Framebuilders
Subject: [Frame] VFD or Phase-a-matic?

 

--
--
You received this message because you are subscribed to the Google
Groups "Framebuilders" group.
 
Searchable archives for this group can be found at http://groups.google.com/group/framebuilders (recent content) and http://search.bikelist.org (older content).
 
To post to this group, send email to frameb...@googlegroups.com
To unsubscribe from this group, send email to
framebuilder...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/framebuilders?hl=en

---
You received this message because you are subscribed to the Google Groups "Framebuilders" group.
To unsubscribe from this group and stop receiving emails from it, send an email to framebuilder...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Dave Dillabough]

Hi Rob,

If you don't have either one a VFD would be a clear winner. If you already
have a phase convertor (either static or rotary) then it would depend on
whether the additional VFD features are of interest to you.

VFD features would include:
-efficiency (uses less power)
-variable speed (from 1/2 to ~2X nominal motor speed)
-programable accell. and decel. times for soft start/stop
-simple remote control. (low voltage potentiometer or switches.
-easy reverse.
-programable over current/temp parameters
-many other programable parameters

The only downsides that I can think of is that the motors tend to make a
little more noise (sort of a whine) and that programming the VFD can be
complex. Once it's running though all you need to do is push the button.

For single phase in/3 phase out the rule of thumb is to double the rating
of the motor to size the VFD. i.e. for a 5 HP motor use a 10 HP VFD. If
the motor is running flat out like a compressor use this rule otherwise it
is overkill. For a lathe/mill or whatever I would use 1.5 X motor.

HTH,

Dave

[Jeremy Kamp]

Rob,

Along with Alex and Dave, I too would always choose the VFD/motor drive over a phase converter.  The only reason I would get a phase converter is if you have multiple machines that would need three-phase power in which a properly sized phase converter would do the trick.  But for one machine, a compact low voltage VFD would be the way to go.

I say compact and low voltage as this is what the industry would call the devices that most shops on this list would be using.  I doubt anyone here is running a 250HP air compressor and needs any voltage larger than 480VAC.

There are many option and choices with VFDs and I would talk with your local electrical/automation distributors about what would be the best fit for you.

Some examples would be:

Automation Direct (online only industrial automation distributor with a large house brand, tends to be cheaper than the bigger well-known names.)

     https://www.automationdirect.com/adc/Shopping/Catalog/Motor_Controls/Drives

Allen-Bradley (part of Rockwell Automation, very highly respected in the industry and great products.)  The Powerflex 4 series is small and still has a lot of features but is still cost-effective.

     http://ab.rockwellautomation.com/Drives/Compact

Siemens

     http://www.industry.usa.siemens.com/drives/us/en/electric-drives/ac-drives/standard-drives/Pages/standard-drives.aspx

Schnieder Electric (owns Square D among other brands.)

     https://www.schneider-electric.us/en/product-subcategory/50020-machine-drives/?filter=business-1-industrial-automation-and-control&parent-category-id=50000

Yaskawa drives (look at their microdrives for up to 25HP motors,)

      https://www.yaskawa.com/products/drives/industrial-ac-drives

And if you do get the VFD, put it in an enclosure to keep chips from getting to it.  Ventilate the enclosure with two openings, one with a fan (computer) and the other with an air filter media.

Hope this helps,

Jeremy Kamp

Orange City, IA
"Kamp Cycles"

[Alex Meade]

I don't think I can add new information, but FWIW, I've had one rotary phase converter (not a Phase-A-Matic) and two Hitachi VFDs.  The rotary unit was a real PITA, requiring a separate start before operating the shop, and it had a loud and very annoying hum.  In comparison, the two Hitachi VFDs go nearly unnoticed.  One of them has a slight 60 cycle hum, but the newer one is almost completely silent except when the built-in demand-based cooling fan is running, and once they're programmed and wired up, they run perfectly.  Like others, I'm not using most of the functions they provide, instead just using them to turn 220V single phase into 220V three phase.  One has an external braking resistor, the other doesn't.  I like the external braking resistor, as it allows me to stop the machine much faster. As others have noted, follow the instructions on enclosing, enclosure size and providing ventilation as needed without letting chips inside.  Expect to spend some hours making the enclosure work, wiring it up and deciphering the programming manual.

Bottom line: If you have a working Phase-A-Matic and it's doing everything you need, unless there's something you really don't like about it, keep using it.  Otherwise, go with a VFD.   If you simply like messing around with new technology stuff and want to explore the many features a VFD offers, that's reason enough to switch too.

Alex Meade

http://www.alexmeade.com/Tools.htm

[peter weigle]

No electrical expert here but I've had a rotary converter for years now and it has powered my whole shop, until recently.

It is sort of a pain to turn it on each time I want to run a machine and it does make some noise I could live without,,, it is a not ideal when doing start and stop operations on my small 2nd op lathe as the rotary is always running, and I can hear it running.

I recently bought 2 big 3 phase buffers that came with Phase-A-Matic static converters and both run perfectly on them with no noise, no programming and no enclosures needed, very simple and I like them a lot.

That said, I would like to slow one of the buffers down at times as it runs at 3600 rpm. I would switch out the static Phase-A-Matic on that one for a VFD,,, but wouldn't consider doing it if the speed was OK because the P-A-M seems so good otherwise.

I might consider buying a P-A-M static for the second op as the lathe has a 2 speed motor and mechanical speed control that works perfectly, so no need for speed control from a vfd on that machine.

Just say'n.

PTR

--

--
You received this message because you are subscribed to the Google
Groups "Framebuilders" group.
 
Searchable archives for this group can be found at http://groups.google.com/group/framebuilders (recent content) and http://search.bikelist.org (older content).
 
To post to this group, send email to frameb...@googlegroups.com
To unsubscribe from this group, send email to

framebuilders+unsubscribe@googlegroups.com

For more options, visit this group at
http://groups.google.com/group/framebuilders?hl=en

---
You received this message because you are subscribed to the Google Groups "Framebuilders" group.

To unsubscribe from this group and stop receiving emails from it, send an email to framebuilders+unsubscribe@googlegroups.com.

[omar-...@cox.net]

Just a plug for Phase-A-Matic.  I have both my mill and lathe running through the same PAM.  Same set up for 30 years.  No issues, ever on this set up.  Of course I don’t run both machines at the same time since I am by myself.

Omar Khiel

Oasis Custom Cycles LLC.

 

From: peter weigle

Sent: Thursday, November 23, 2017 5:10 PM

To: Alex Meade

Cc: Framebuilders

Subject: Re: [Frame] Re: VFD or Phase-a-matic?

 

No electrical expert here but I've had a rotary converter for years now and it has powered my whole shop, until recently.

It is sort of a pain to turn it on each time I want to run a machine and it does make some noise I could live without,,, it is a not ideal when doing start and stop operations on my small 2nd op lathe as the rotary is always running, and I can hear it running.

 

I recently bought 2 big 3 phase buffers that came with Phase-A-Matic static converters and both run perfectly on them with no noise, no programming and no enclosures needed, very simple and I like them a lot.

 

That said, I would like to slow one of the buffers down at times as it runs at 3600 rpm. I would switch out the static Phase-A-Matic on that one for a VFD,,, but wouldn't consider doing it if the speed was OK because the P-A-M seems so good otherwise.

 

I might consider buying a P-A-M static for the second op as the lathe has a 2 speed motor and mechanical speed control that works perfectly, so no need for speed control from a vfd on that machine.

 

Just say'n.

PTR

On Thu, Nov 23, 2017 at 3:52 PM, Alex Meade <alexd...@gmail.com> wrote:

--

--
You received this message because you are subscribed to the Google
Groups "Framebuilders" group.
 
Searchable archives for this group can be found at http://groups.google.com/group/framebuilders (recent content) and http://search.bikelist.org (older content).
 
To post to this group, send email to frameb...@googlegroups.com
To unsubscribe from this group, send email to
framebuilders+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/framebuilders?hl=en

---
You received this message because you are subscribed to the Google Groups "Framebuilders" group.
To unsubscribe from this group and stop receiving emails from it, send an email to framebuilders+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

--
--
You received this message because you are subscribed to the Google
Groups "Framebuilders" group.
 
Searchable archives for this group can be found at http://groups.google.com/group/framebuilders (recent content) and http://search.bikelist.org (older content).
 
To post to this group, send email to frameb...@googlegroups.com
To unsubscribe from this group, send email to

framebuilder...@googlegroups.com

For more options, visit this group at
http://groups.google.com/group/framebuilders?hl=en

---
You received this message because you are subscribed to the Google Groups "Framebuilders" group.

To unsubscribe from this group and stop receiving emails from it, send an email to framebuilder...@googlegroups.com.

[Alex Meade]

Peter,  good info. Thanks for this.

IIRC, the PAM static units will run a 3P motor at 2/3 the rated power of the motor.  I assume you’re not affected by the loss of power on your buffers (?)

Also, for others who might be interested, the PAM static converters can be made to operate 3P motors at full power if an idler motor is incorporated into the conversion.  There are a bunch of caveats to this method, but interestingly, if a static PAM is combined with an idler (really, just a used 3P motor you’ve scrounged), the combined system of PAM plus idler motor will run larger 3P load motors than will the static PAM alone, and the static PAM needs to be sized to the idler motor, not the load motor(s).

A static PAM is different from a VFD of course, but the VFD, even though it’s a solid state device with no moving parts, will run a 3P motor at full power.

If I have nay of this wrong, I’m sure someone will correct me (and thanks in advance for doing so!)

Alex

http://www.alexmeade.com/Tools.htm

[James Swan]

When you combine a static phase converter with an idler motor, as Alex describes, what you wind up with is a rotary phase converter. 

A static converter is a made up of a group of capacitors that take two legs of single phase power (that are 180 degrees out of phase) and move them into a 120 degree out of phase configuration so they can power two of the three windings in the three phase motor.

That’s how you wind up getting 2/3 of the power out of the machine you’re running.

Using one is supposed to be stressful to older motors, but I know lots of people who use them to run ancient machine tools and nobody seems to have trouble...

When you use the two phases coming out of a static converter to drive an idler motor then the third winding in the idler motor becomes a generator and “manufactures” the third leg.

IIRC the idler motor must be one and half times larger then the motor you intend to power.

It’s recommended that you don’t run the manufactured leg through the switch gear of your machine tool.

The tricky part of getting all this to work properly is the balancing of the capacitors…

That’s as much as I know about the subject.

I run my shop on a commercially made 5HP rotary phase converter. It’s up in the loft above the shop, and I’ve got it sitting on a couple thick slabs of styrofoam to quiet it down a little.

I can still hear it a little, and yeah, I have to turn it on and off, but it’s fine for my part time use.

Jamie

James B Swan

H: 631-754-1457
C: 516-238-6782
W: 516-403-5945
http://www.jamieswan.net

http://www.limws.org
http://www.liatca.org
http://www.webb.edu

framebuilder...@googlegroups.com

For more options, visit this group at
http://groups.google.com/group/framebuilders?hl=en

---
You received this message because you are subscribed to the Google Groups "Framebuilders" group.

To unsubscribe from this group and stop receiving emails from it, send an email to framebuilder...@googlegroups.com.

[M-gineering]

I'm often mildly frustrated by all the cheap machinery, tooling, parts
etc you can pick up in the States, so this subject makes me feel really
smug for a change. I've got three 3 x 30 Amp circuits (and standard 220V
2 phase) in the shop ;)
--
mvg

Marten Gerritsen
Kiel Windeweer
Netherlands

[peter weigle]

Alex said,

"IIRC, the PAM static units will run a 3P motor at 2/3 the rated power of the motor.  I assume you’re not affected by the loss of power on your buffers (?)"

Alex, all true,,, but the big buffer in the background of the shot below,,, would tear anything out of your hands,,, and try and rip your arms out of their sockets,,, even with a 1/3 loss of power,  I'm not affected unless I do something wrong with the other 2/3rds power that remains.

https://www.flickr.com/photos/49353569@N00/38471010041/in/dateposted/

I guess my main point is all of the converters have something to offer.

If you have some reserve power on tap and want a simple conversion that only takes a few minutes to wire up the P-A-M static is pretty nice imo.

If you need a conversion and speed control then the VFD has those features,,, and more, but needs an enclosure and time and knowledge to program it,, (not as simple for a Luddite like me).

If you want one device to run many machines, sometimes 2 or more at once, then a properly sized rotary maybe a good choice?

Again, I'm no expert, but have some experience with at least 2 of the 3 options.

I think it's great that there are several options for converters. I have had fun running that buffer straight off my rotary converter to test it, and then wiring in the static converter and still have it run real well at the flip of one switch (and with no additional noise in the background when I shut the buffer off).

The next step may be to try a vfd so I have a phase converter,,, and a speed controller all in one.

Again, all good.

Best to all,

PTR

[Alex Meade]

Thanks to all.  This has been an informative and helpful discussion - at least for me.

Peter, that's a honkin' buffer you have there.  I can certainly see why you'd not be bothered by one missing phase!

Alex

http://www.alexmeade.com/Tools/

On Wednesday, November 22, 2017 at 12:22:07 PM UTC-5, Rob Clark wrote:

[Eric Keller]

Chiming in late, I just get a vfd for each machine.  I didn't want to spend enough on the last one (5hp) to get a high-end vfd or waste my time on ebay looking for one, so I just bought a Huan Yang, which seems to be the hobbyist VFD of choice.  Might not be the best choice if you have a high inertia machine, but it works fine on my lathe so far.  I do have an enclosure for all of them, but I don't think it's really necessary.  Look on youtube for people's setup.

Eric Keller

Boalsburg, Pennsylvania

--

[Cliff McLeroy]

I have a lot of experience with VFDs but little with machine tools. The main advantage I see in a VFD is the variable speed aspect. A VFD can allow a 1750 rpm motor to run as low as ~350 rpm and even lower if it is "inverter rated". It can also allow the same motor to run as high as 2900 rpm though it's best to only do this with inverter rated motors. Also you have a programmable accel and decel rate. So instead of your motor accelerating the machine at max torque, it can ramp it up slowly and gently. It can also stop the machine quicker if you install a braking resistor. It consumes close to zero power when it is stopped. And lastly the efficiency is much better with a VFD so not only will you be saving $ and CO2, but it may allow more horsepower with your existing electrical capacity.

-Cliff McLeroy 

On Wednesday, November 22, 2017 at 12:22:07 PM UTC-5, Rob Clark wrote: