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Bob Brandl

Phase converters...

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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

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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?

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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. 

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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.

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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.

 

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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.

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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.

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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

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