Jump to content
I Forge Iron

Phase converters...


Recommended Posts

15 hours ago, AlanB said:

I realize that this is obvious and you are probably set on operating 3 phase but it occurs to me that if this was the only 3 ph equipment in my shop and my power was limited to single phase, I would just buy a 15hp single phase motor with suitable pulleys to produce desired speed and forget fooling with phase converters or the cost of adding 3 phase power to the shop. No?

Here's a 10hp single phase compressor duty 1750rpm from Northern Tools for $850

http://www.northerntool.com/shop/tools/product_200381915_200381915

(you might not get much more than 10hp from a 3ph 15hp running on a converter)

My 15 Hp converter collectively cost about a third of the cost of that motor (less shipping of course) and the flexibility of the converter provides value far beyond the use of a single machine.

At least it does for my uses. One big machine tool often leads to more. Once you buy or build the converter, you got it. Biggest advantage for me is it powers three phase welding machines. Again, for my uses this is a huge value and advantage. 

Mostly a matter of what you plan to do and what you want to spend.

IMHO of course

Link to comment
Share on other sites

  • Replies 56
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

I may need to call American Rotery. I am in the process of purchasing a 4B, and had plans to throw it in my family shop that has 480v 3ph power. However, considering the foundation, I may wait and place it at our new home. I really want to set it, and move it only after I die. So with that said....

 

The Nazel 4B has a 15hp motor. I have always heard that phase converters give you only a fraction of power, and to get around this (And I have read about a guy having to do this for his Beche that ran a 15hp motor) you need to double the rotary motor. So a 15hp motor needs a 30hp converter to get full power?

Link to comment
Share on other sites

No, you buy the converter to match your motor. I have an ARCO Roto-Phase that will start up to a 15hp motor and run a combined 60hp. But I usually go a little higher just because I like to have some extra to work with.

You may be thinking of having to go bigger when using a "jack" motor. When using another 3 phase motor to trick the equipment into thinking it is getting 3 phase when using single phase you get a 33% loss in power. That is how I ran my machine shop equipment at my Dad's workshop for many years as he only had 220v single phase available. The lathe was a 5hp, and I used another 5hp 3 phase motor to wire through. You pull start the "jack" motor , then turn the power on. The 3 phase motor will stay running, and then you just start the machinery like normal. Because the single phase 220 only has two hot legs , and not the 3 that 3 phase has you get that 33% loss. So if you have a 3 hp motor , you can only use 2 hp of it. 

Link to comment
Share on other sites

Ok. I havent had the need to study the ins and outs of phase converters and read that in passing, and can see now why I confused the two. Good to know. It makes the cost a little different. Wish I could find where I read about the Beche hammer however. May have been an owner of one selling on facebook.

 

Thanks.

Link to comment
Share on other sites

  • 2 months later...

I have had good experiences with both VFD's and rotary converters.  I use both in my shop.  You do have to be careful in sizing either the VFD or the rotary converter.  I worked with TEMCO out of the west coast and their engineers were very helpful in telling me the pro's and con's as well as the proper sizing for converters.  You do have to be careful to get the right size converter for your hammer.  Here is a link to Temco:  https://www.temcoindustrial.com/product-guides.html

Good Luck.

 

Link to comment
Share on other sites

  • 4 months later...

Ok, so differing opinions on this.

Others in the know have informed me that I do Infact need to increase my phase converter size to my Nazel motor because my Nazel motor is powering a high load compressor.

 

I am told with the bypass open I can get away with running it on a converter 1/3 at least stronger than my 15hp. Without the bypass, probably double and will need a 30hp converter.

 

So along with powering a high load compressor there is also the giant gear.

Link to comment
Share on other sites

  • 2 weeks later...

After more research, the consensus is yes, for a machine like this, it is categorized as a "hard load", and a 15hp converter will not suffice for the 15hp motor on my hammer. With the bypass always open on start up, I should be able to get away with a 25hp converter.

Thanks James. In the end, I will be on the phone with a representative with whichever brand converter I purchase.

Link to comment
Share on other sites

  • 2 years later...

If it is just for the beaudry, and you dont have a motor, just find a single phase 10 hp. A 1p should be ok. My experience with converters has been mixed. I built three in my shop with no problems or complaints. At work, we use a mix of static converters ( will make you wish you had shelled out for a single phase motor) and vfd drives. Vfds cost about the same as a magnetic starter and probably the most reliable off the shelf solution. An air hammer like a beche or nazel has a full load at starting which seems to cause issues with some converters. I always sized my rotary converters 1 to 1 to the driven motor without issue. The one in the picture is a 7.5 hp I put together for the 250.

20180729_155035.jpg

Link to comment
Share on other sites

  • 7 months later...

I run a LeBlond lathe 10hp 3 phase, off of a 3 phase motor sitting on the floor.  Thing about 3phase motors is that they will run just fine on single phase 220, but they will not start.

   I run the "converter" motor on 220, it generates the third leg for the 3 phase motor on the lathe.  I start the "converter" motor with a pull rope. Once it's running, I leave it running, until I'm finished working with the lathe.  

  One thing to remember is that the motor on the floor absoloutely has to be the same or greater hp.  

3 phase motors are cheap, compared to single phase of same hp.

Link to comment
Share on other sites

  • 2 months later...

I have a Phoenix 40HP rotary converter..   From them  I can run any combination up to 40hp at full load or any combination.. they just all need to be started singly.  They should not be all started at the same time. 

There is a lot of information as to proper sizing because of idle loads (constant current draw while idling), windings load or over current at the capacitors from being under powered.. IE to much voltage..  In other words you don't want a 40hp to run only a 2hp motor..   

I only power smaller motors because I planned on having it for a larger demand usage. 

3 ph motors used to be a lot cheaper when industry was going out and then you could buy what ever for pennies.. 

Today a brand new 3 ph motor is the only option for certain applications where the motor has to change direction  CW/CCW.   As the motors get larger 1ph motors get expensive really quickly..  I mean they all do, but there is a substantial increase with the 1ph vs 3ph. 

Getting the 3rd leg to be balanced is where have or adding caps come in.   What usually happens is one leg will be a little low. 

Over the years there have been many solutions..   Rip cord starts,  pony motors,  capacitor start..  Really they are pretty simple in concept.  Happy trails. 

Link to comment
Share on other sites

  • 1 year later...

Old thread but wanted to add a little to it. I work in the electrical industry at a distributor. When I was in sales I would get people who came in all the time telling me how they got an amazing deal on a compressor or some other kind of machine only to get home and realize it was 3 phase. I would typically recommend Ronk. They make several different convertors and I have never heard bad things from those whom I sold some to. Granted it was typically a farmer buying them so they didn't have to buy giant single phase motors.

If you are running machinery that has a very fine tuned voltage that is has to run on, SQD (Square D / Schneider Electric) makes a sort of phase "conditioner" that can help keep everything running steady. They also have a solid line of VFD's that can be expertly tuned (if you are willing to shell out some $$ anyways).

When sizing a converter, you should look at the line side load you are trying to power. If your line side has a motor on it (which I would assume nearly it always does or you probably wouldn't need the converter), look at the motors ratings. Your converter will have to be large enough to deal with the in-rush of start up. Main reason a 15 HP convertor typically wont start another 15 HP motor is because the motor on the line side pulls more power trying to start then the load side supplies it with. A short example would be say your 15 HP motor runs is rated for 15A (just made up numbers), during start up, it could take up to THIRTY amps to get that bad boy rolling. So as you can see, if you tried starting that motor with the same size motor, it wouldn't work as it would more than likely stall out the other motor trying to fire it up.

Depending on the size of the motor, I would probably recommend a combination starter to handle it. Would provide a nice means of start/stop, disconnect and overload protection.

I am not an electrician by any means. I am just a guy who has worked in the industry for over a decade now and have learned a lot talking to the lifers during day to day work. Most are more than willing to talk about the trade and explain things when they have time, so you just pick it up as you go. Always feel free to ask me any questions. Full disclaimer though. I will NOT tell you how to size your wire or how to wire things up. Don't want anyone trying something and causing a fire or getting themselves killed.

Link to comment
Share on other sites

SLAG,

Here. Note to IFI 'ers

VFD  does  not mean voluntary fire department.  

It probably stands for "variable frequency drive.

Please do not take my word for it check it out here,

vfd def - Bing

Mr. Bing is usually correct.

Sincerity, 

SLAG.

Link to comment
Share on other sites

Herr Frosty, und Herr, Powers,

Passing strange my telephone book said the same.

But I, the SLAG,  thinks that it may, still, mean "variable frequency drive". 

Let the readers be the final judge'(s).

SLAG.

Link to comment
Share on other sites

3 hours ago, SinDoc said:

Old thread but wanted to add a little to it.

Fellows, I, having three each, three phase Walker Turner drill presses, and a rotary phase converter in storage, am grateful that SinDoc has resurrected this thread. Thus, methinks, that VFD must stand for:  Very-Fine-Dredging :rolleyes:

Robert Taylor 

Link to comment
Share on other sites

22 minutes ago, Anachronist58 said:

Thus, methinks, that VFD must stand for:  Very-Fine-Dredging 

Ah HAH! So adding panko crumbs to the flour in which I dredged the flounder filets I fried up for dinner made it into a NOT VFD!

Messr Slag: I thought a variable frequency drive was the route I drove when traffic was bad. 

Frosty The Lucky.

Link to comment
Share on other sites

Very Funny Decision

I learned about in-rush (start up) of motors when I installed my first home generator for power outages. I picked up a 3.5 kw generator welder combo and the only way I could run the well was to disconnect just about everything in the house so the generator would handle the pump start up. After several years doing that, the decision was made to upgrade the generator to an 8 kw generator which will handle the pump and the rest of the house, with the exception of the electric wall furnace (9.2 kw).

PS:

That story was brought to mind because this morning Carroll Flicker & Flash struck again. About 0930 the power went out. I waited about a half hour, because the guys are really very good at getting it up and running, then fired the generator up. It ran the whole house for 3 hours without a hiccup. It needed to be run anyway because it was the first time I used it in about a year. Generators should be "exercised" a couple times a year if they aren't used but lately I've gotten lax and thought what better time to give it a work out.

Edited by Irondragon ForgeClay Works
PS
Link to comment
Share on other sites

Virally Frivolous Digression...

Jerry you are making my mouth water...

Yes, just recently learned a bit about inrush current whilst studying variable transformers (Variac).  I am Sure that when I finally hire an Electrician, he or she will likely rip out all of my additions/modifications... 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...