Rotary Phase Converter, Var. Freq Drive or Hybrid- What would you choose?

Rotary Phase Converter, Var. Freq Drive or Hybrid- What would you choose?

Joined: December 22nd, 2010, 2:41 am

June 22nd, 2011, 5:35 am #1

Currently wiring up a shop, thought I had 3-phase accessibility, but the Electric Co now says nix, add $6K for 3-Phase- deal breaker for me....

Power/Machines: (All already wired 3PH)- 1- 5HP Lathe, 1- 2HP Bridgeport, 1- 2hp 3Ph grinder. Use is light, more hobby level, retired several years ago and now just playing- I just need Lathe and Mill running to make 'stuff' as desired... Once you get use to have the access, it is hard to get along without it!

Electrician says history is in favor of a quality Rotary Phase Converter, CNC qualified being the best. He does not have a lot of experience with a VFD (Variable Freq Drive) but notes they are 1/3 - 1/2 the cost of the Rotary Phase converter. He goes on to honestly state there are solid circuit drives and hybrids that he has no experience with.

What would your choice be and why?

Thanks in advance for your time and consideration in responding.

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Joined: November 15th, 2004, 12:42 pm

June 23rd, 2011, 11:51 am #2

VFD's.. I got my first one when I bought a Clausing 5914 3phase lathe about 5 yrs ago.. It seemd the best way to go..After using it for about 6 months, (and enjoying all of the benefits of a VFD) such as no noise, variable speed etc... Then,
The single phase motor on my Grizzly was overheating(chinese 2hp) and it was out of warranty. So, bought a 1hp 3phase motor, another VFD, and man, am I glad I did!
Variable speed on the mill is terrific and I use it all the time.. Power tapping and tweaking the speed for best operation, I have never looked back!
Torque is down on the slower speeds, but so far I haven't had a problem..
Mike
Here's a photo of my setup
I have both VFD's control power set up to run thru a DPDT relay, so the switch shown is a way to kill power to both. I also installed a manual clock timer in series with that kill switch because i kept forgetting to turn the VFD's off when I quit for the day. The timer is set for 1-6 hours, and it kills both after the preset time..
This gives you an idea of how quiet the VFD's (no noise mostly)


" Ever have one of those mornings where it hardly seems worth the effort to chew through the leather restraints? "
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Joined: June 7th, 2010, 12:14 am

June 23rd, 2011, 11:22 pm #3

Currently wiring up a shop, thought I had 3-phase accessibility, but the Electric Co now says nix, add $6K for 3-Phase- deal breaker for me....

Power/Machines: (All already wired 3PH)- 1- 5HP Lathe, 1- 2HP Bridgeport, 1- 2hp 3Ph grinder. Use is light, more hobby level, retired several years ago and now just playing- I just need Lathe and Mill running to make 'stuff' as desired... Once you get use to have the access, it is hard to get along without it!

Electrician says history is in favor of a quality Rotary Phase Converter, CNC qualified being the best. He does not have a lot of experience with a VFD (Variable Freq Drive) but notes they are 1/3 - 1/2 the cost of the Rotary Phase converter. He goes on to honestly state there are solid circuit drives and hybrids that he has no experience with.

What would your choice be and why?

Thanks in advance for your time and consideration in responding.
VFD for each machine. You will get spoiled by the variable speed convenience.

You can purchase the single phase in, three phase out variety, or just purchase good quality three phase drives with two times rated capacity for the motors you need to power. That is, a 1 hp three phase motor requires a 2 HP 3ph VFD fed by single phase lines. The rectification diodes are the only part that cares about the incoming power. (It's possible to power a large number of VFD's on a single DC bus!)

The better VFDs offer improved low speed performance than do straight (cheaper) V/F drives. The VFD's take a bit of a learning curve to set up, that's a draw back...

I have several VFD's and a home built "spinner". I like the VFD's.

An aside, I keep the VFD's energized all the time. It's good for the capacitors

Cheers
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Joined: June 16th, 2009, 7:43 pm

June 24th, 2011, 12:58 am #4

an inline breaker on the single phase side might be required?

"Silence is the only thing that can hinder the Truth"
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Joined: May 8th, 2001, 4:06 pm

June 24th, 2011, 6:53 am #5

Currently wiring up a shop, thought I had 3-phase accessibility, but the Electric Co now says nix, add $6K for 3-Phase- deal breaker for me....

Power/Machines: (All already wired 3PH)- 1- 5HP Lathe, 1- 2HP Bridgeport, 1- 2hp 3Ph grinder. Use is light, more hobby level, retired several years ago and now just playing- I just need Lathe and Mill running to make 'stuff' as desired... Once you get use to have the access, it is hard to get along without it!

Electrician says history is in favor of a quality Rotary Phase Converter, CNC qualified being the best. He does not have a lot of experience with a VFD (Variable Freq Drive) but notes they are 1/3 - 1/2 the cost of the Rotary Phase converter. He goes on to honestly state there are solid circuit drives and hybrids that he has no experience with.

What would your choice be and why?

Thanks in advance for your time and consideration in responding.
although I haven't had a rotary phase converter, so no experience there.

I got a used millrite a while back, which came with a 3 phase motor. So I had to do something to power it up and the vfd is a pretty easy solution. Its relatively affordable, and if you are into finer tuning your equipment, most vfd's allow for lots of programming options.

I just use mine for the conversion to 3 phase and for speed control. That is, you can change speeds on your machine, within a reasonable range, simply by pushing buttons on the vfd. Way easier than changing belts or gears.

Pacific Airgun Expo
email: pae@pacificairgunexpo.com
website: www.pacificairgunexpo.com
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Joined: June 7th, 2010, 12:14 am

June 24th, 2011, 10:21 pm #6

an inline breaker on the single phase side might be required?

"Silence is the only thing that can hinder the Truth"
All electrical equipment needs "protection".

Everything I wire in my shop goes back to a breaker.

A VFD does NOT want to see the line between the VFD and the motor with a switch or breaker however.

Cal
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Joined: December 22nd, 2010, 2:41 am

June 26th, 2011, 4:35 pm #7

Currently wiring up a shop, thought I had 3-phase accessibility, but the Electric Co now says nix, add $6K for 3-Phase- deal breaker for me....

Power/Machines: (All already wired 3PH)- 1- 5HP Lathe, 1- 2HP Bridgeport, 1- 2hp 3Ph grinder. Use is light, more hobby level, retired several years ago and now just playing- I just need Lathe and Mill running to make 'stuff' as desired... Once you get use to have the access, it is hard to get along without it!

Electrician says history is in favor of a quality Rotary Phase Converter, CNC qualified being the best. He does not have a lot of experience with a VFD (Variable Freq Drive) but notes they are 1/3 - 1/2 the cost of the Rotary Phase converter. He goes on to honestly state there are solid circuit drives and hybrids that he has no experience with.

What would your choice be and why?

Thanks in advance for your time and consideration in responding.
the Electrician is concerned about the HP running thru converter, and the possibility of a TIG being used occasionally. I think that more than anything he is an older fella that has used a lot of converters when there was major mfg in the area and he probably does not have the same comfort with the electronics and programming that the VFD implies. I think my compromise is going to be both. Split the system and use a converter in one area of the shop and a VFD in another (and gain the experience in using a VFD that I don't have). I know it less efficient, but it is also a safe bet- I live in a fairly rural area, the closest significant city being 1.5hrs away- thus the drive to use known local tradesmen (no pun intended).

You guys have really peaked my interest in the VFD, which seems to be more available in the smaller sizes and cost less. Now I'm going to have to find out more! Thanks again for the input, it is appreciated!
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Joined: October 25th, 2002, 3:46 pm

June 30th, 2011, 11:04 pm #8

VFD's.. I got my first one when I bought a Clausing 5914 3phase lathe about 5 yrs ago.. It seemd the best way to go..After using it for about 6 months, (and enjoying all of the benefits of a VFD) such as no noise, variable speed etc... Then,
The single phase motor on my Grizzly was overheating(chinese 2hp) and it was out of warranty. So, bought a 1hp 3phase motor, another VFD, and man, am I glad I did!
Variable speed on the mill is terrific and I use it all the time.. Power tapping and tweaking the speed for best operation, I have never looked back!
Torque is down on the slower speeds, but so far I haven't had a problem..
Mike
Here's a photo of my setup
I have both VFD's control power set up to run thru a DPDT relay, so the switch shown is a way to kill power to both. I also installed a manual clock timer in series with that kill switch because i kept forgetting to turn the VFD's off when I quit for the day. The timer is set for 1-6 hours, and it kills both after the preset time..
This gives you an idea of how quiet the VFD's (no noise mostly)


" Ever have one of those mornings where it hardly seems worth the effort to chew through the leather restraints? "
interesting wiring methods.....

Take care eh!

Walter....
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Joined: October 25th, 2002, 3:46 pm

June 30th, 2011, 11:09 pm #9

Currently wiring up a shop, thought I had 3-phase accessibility, but the Electric Co now says nix, add $6K for 3-Phase- deal breaker for me....

Power/Machines: (All already wired 3PH)- 1- 5HP Lathe, 1- 2HP Bridgeport, 1- 2hp 3Ph grinder. Use is light, more hobby level, retired several years ago and now just playing- I just need Lathe and Mill running to make 'stuff' as desired... Once you get use to have the access, it is hard to get along without it!

Electrician says history is in favor of a quality Rotary Phase Converter, CNC qualified being the best. He does not have a lot of experience with a VFD (Variable Freq Drive) but notes they are 1/3 - 1/2 the cost of the Rotary Phase converter. He goes on to honestly state there are solid circuit drives and hybrids that he has no experience with.

What would your choice be and why?

Thanks in advance for your time and consideration in responding.
so if you need a 10hp load on three phase you will need a 15hp rated single phase 240VAC input VFD

You cannot use the variable frequency function of the drive unless you supply a seperate circuit for the controls on the machine. That is no problem just requires you plug in the 120VAC controls circuit seperately from the drive.

I run my 20x80 Kingston lathe on a drive and my Holke mill has its own drive. Works great. electronics in these VFDs are light years better than they were 20 years ago.

Enjoy the machines.
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Joined: December 25th, 2010, 4:18 pm

July 8th, 2011, 2:16 am #10

Currently wiring up a shop, thought I had 3-phase accessibility, but the Electric Co now says nix, add $6K for 3-Phase- deal breaker for me....

Power/Machines: (All already wired 3PH)- 1- 5HP Lathe, 1- 2HP Bridgeport, 1- 2hp 3Ph grinder. Use is light, more hobby level, retired several years ago and now just playing- I just need Lathe and Mill running to make 'stuff' as desired... Once you get use to have the access, it is hard to get along without it!

Electrician says history is in favor of a quality Rotary Phase Converter, CNC qualified being the best. He does not have a lot of experience with a VFD (Variable Freq Drive) but notes they are 1/3 - 1/2 the cost of the Rotary Phase converter. He goes on to honestly state there are solid circuit drives and hybrids that he has no experience with.

What would your choice be and why?

Thanks in advance for your time and consideration in responding.
Have been using it since 1990 without any issues so far , it will start a 20 hp and run a total of 50 hp.

Life is good here in hot&humid Louisiana
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