# Phase converter to operate blender?



## nrp3 (Jan 24, 2009)

I have a customer that bought a 480v 3 phase blender for his dog food company. Naturally, he doesn't have but 240/120v single phase service at his warehouse. The manufacture can send us a 208v 3 phase VFD to replace the one on the unit and said we can rewire the motor. I was looking at the TEMCo website and phase converters seem like a reasonable way to go. That is 240v single phase to three phase. Actually waiting for a call back from them. Anyone done this before?


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## micromind (Aug 11, 2007)

I've installed a number of phase converters over the years. 

The rotary ones are far superior to the static ones, though they cost more. 

They're a cinch to install if they drive just one motor. Actually, they're pretty easy for more than one as well. 

One thing to watch out for, on most phase converters, the manufactured phase is A. Be careful to not connect anything (like controls) to this phase. 

Another way to run a 3 phase motor on single phase is by using a VFD. Smaller ones (under 5HP) are readily available with 240 single phase in and 240 3 phase out. 

Either method will run the motor, installation and operation can be slightly more involved with the VFD, mainly because of programming and controls. 

Rob


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## Electric_Light (Apr 6, 2010)

How big is the motor? Does he need the blender to provide full rated output?


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## MDShunk (Jan 7, 2007)

Given your two choices, I would ABSOLUTELY NOT install a phase converter in this case. Get the VFD from the manufacturer and go that route. Far more reliable, and less things to maintain. Cheaper too.


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## 4Runner (Apr 4, 2010)

MDShunk said:


> Given your two choices, I would ABSOLUTELY NOT install a phase converter in this case. Get the VFD from the manufacturer and go that route. Far more reliable, and less things to maintain. Cheaper too.



Interesting. That's the exact opposite of what I would have thought, as a phase converter is dirt simple while a VFD has lots of electronic components that can fail. But, I don't work with VFD's at all so I'm guessing they are robust enough to last a long time.


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## MDShunk (Jan 7, 2007)

4Runner said:


> Interesting. That's the exact opposite of what I would have thought, as a phase converter is dirt simple while a VFD has lots of electronic components that can fail. But, I don't work with VFD's at all so I'm guessing they are robust enough to last a long time.


My guess is that the mixer has a VFD in it already, for speed control of the mixer, and the manufacturer suggests sending a replacement more suitable for the available voltage and phase configuration. Even if that's not the case, the VFD is very often cheaper than a phase converter, and gives you the added flexibility of speed control. Also, in the case of a mixer, it would give you the ability to reverse it if something jammed up (like a human arm?). Additionally, you won't have the additional energy being used, like you would if you ran a rotary phase converter. They use a decent amount of power in and of themselves. When you can use a VFD instead of a phase converter, I am a big fan of that option for many reasons... mostly economic reasons.


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## 4Runner (Apr 4, 2010)

Do they make purpose built VFD's specifically for powering a 3-ph motor off a 1ph supply, or do you just buy an off the shelf VFD and configure accordingly?


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## MDShunk (Jan 7, 2007)

4Runner said:


> Do they make purpose built VFD's specifically for powering a 3-ph motor off a 1ph supply, ..


Yes, but only up to a certain horsepower. That varies by manufacturer. Rule of thumb; it's only up to about 5hp that you can buy a VFD for single phase in, 3-phase out. Bigger than that, you're stuck with the phase converter option or consider building a 3-phase service if much more 3-phase equipment is planned. 

If this customer is a dog food manufacturer, he should probably budget for a 3-phase service sometime in the future. If things work out for him, he's going to need it sooner or later.


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## Electric_Light (Apr 6, 2010)

Its hard to brainstorm solutions without knowing the size of the motor and nature of the work. 

If this is a 15hp beast, does not need to be variable speed drive, and will be cycled on and off a lot, I would say rotary converter. 

Utilities may impose a limit on starting current or number of starts an hour. Given that it's a 120/240v split phase single phase, there are probably other customers on the same distribution transformer and they are going to complain with the constant light flicker. 

The rotary converter doesn't need to be cycled that often and the flywheel inertia will cushion the starting current so that it won't cause disturbance for other users.

Using the VFD is like using your gas pedal to accelerate your car while starting across the line is like keeping the RPM at 3600, matching the speed with gas, then using the clutch to bring the rotor up to speed. This isn't a big deal for low-inertia load, such as the A/C on your car, but it would be a problem for accelerating the whole vehicle. 

VFD should be considered for highly inertial load, like a fan motor with a huge squirrel cage fan attached, centrifuge, etc.


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## nrp3 (Jan 24, 2009)

The machine is a Ross ribbon blender. 480v 3 phase, 1 motor 7.5 hp/5.5 kw. It has an AC Tech VFD control already on it. I talked to TEMCo on the phone yesterday and they claim that their rotary phase converters would operate it just fine. I can either step up 240v single phase to 480v single phase with step transformer and run through a 480v phase converter or get a 208/240? 3 phase VFD from the Ross Factory, rewire the motor for 208/240? and feed it all with a phase converter of the same voltage skipping the step up transformer. The factory would send me a new VFD at no charge. 

I don't do a lot of this work and its an expensive machine (to me $18000). I just want to get it right. We are also looking at leasing a 480v generator. The owner doesn't expect to stay at this location long, thats why the service upgrade isn't likely. Its a typical nasty commercial setting built in sections over time and hard to get wiring from one end of the building to the other. I told him to call before he bought any other machinery first and to make sure the next building had 480/277 and 208/120.


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## nrp3 (Jan 24, 2009)

Looking at the Temco site, I guess a mixer would be considered hard start? This piece of equipment will likely be used for no more than 20 minutes at a time, maybe once a day or every other day.


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## John Valdes (May 17, 2007)

You would be foolish to go with the converter when the blender is already set up for the AC Tech VFD. Why reinvent the wheel??????????
So simple man! Replace the VFD with the new one and reconnect the motor for 240 volts.


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## MDShunk (Jan 7, 2007)

John Valdes said:


> You would be foolish to go with the converter when the blender is already set up for the AC Tech VFD. Why reinvent the wheel??????????
> So simple man! Replace the VFD with the new one and reconnect the motor for 240 volts.


Particularly since the factory is willing to send a new VFD for free. That makes it a no-brainer, for me.


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## nrp3 (Jan 24, 2009)

Ok, so I don't get flamed too badly, yes I am licensed, run a small business, etc, etc. Enlighten me. If I swap the VFD, it will run without three phase input? I need to take a look at the AC tech website, probably call them too. What I don't want to do is violate the warranty. This stuff is all new to me, being a mostly residential guy. What I want to do is not make it any tougher when he moves to a building with the correct service.

I suppose this makes sense, since the well pump controller for the geothermal system I hooked up a year ago had that. Hmmm...


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## MDShunk (Jan 7, 2007)

Just keep the existing VFD when they send you the new one, for when the machine eventually moves.

Heck, if it's the manufacturer sending you the replacement VFD, there's really no way you can violate any warranties. If the manufacturer is the one sending you the new part, that actually helps you a ton. There can never be any finger pointing down the road. They're the one's that spec'd the conversion. 

I really think you're putting way too much thought into this. Roll with the factory's advice... it's their machine.


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## nrp3 (Jan 24, 2009)

I don't know enough about the VFD to know whether it will accept single phase input. I was under the impression that I would be receiving a three phase in/three phase output arrangement. It seems so simple...


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## MDShunk (Jan 7, 2007)

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nrp3 said:


> I don't know enough about the VFD to know whether it will accept single phase input. I was under the impression that I would be receiving a three phase in/three phase output arrangement. It seems so simple...


Did you tell the factory people what you have?? That would be step #1. It's a new machine. Make them do the legwork. Equipment manufacturers will normally bend over backwards to have everyone happy with their machine. Put the engineering in their court. That's how you play the game. Confess to them that you haven't got a clue, and they'll help you. Trust me. I've made a lifestyle of out messing around with electrical stuff that I haven't got the first clue about. The factory is your friend.

Additionally, seldom should you take as gospel what any 3rd party manufacturer tells you (like the phase converter people). In this case, they're right (their converter will run your machine), but they've got other interests in mind (like selling their product). ALWAYS be very suspicious of 3rd party manufacturer's advice. Often, you need it, but take it for what it's worth... part of their sales process.


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## nrp3 (Jan 24, 2009)

From what I remember from talking with the factory, they are aware that we don't have three phase in any form. The largest single phase blender is a third of the size, not big enough to do the job, no surprise there. They haven't gone down the road we have about the VFD handling the phase issue. Sounds like a question for AC Tech. One of the guys at the supply house was talking about the possibility of a VFD being able to do this, but that it might have to be a larger unit than the one likely being sent.

Thanks for the help by the way.


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## nrp3 (Jan 24, 2009)

Took a moment to look at the AC Tech website and the VFD I have now is a three phase input, the equivalent one in the 240v is also three phase input. They don't seem to list ones in the size I need with a single phase input. I'll keep looking.


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## Electric_Light (Apr 6, 2010)

The blender manufacturer didn't intend it to be used in a place without 3 phase power. Aside from finding a 240v 1ph input VFD intended for driving a 3ph 480v motor of your size, you'll still need a rotary converter to provide 3ph. 

Get the mfgr to get you the 208 or 240v VFD, then get a 230-1ph to 230-3ph rotary converter.


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## PRECISION_JC (Apr 6, 2010)

Because you have a motor of that size and only have 1ph power you will need a Phase converter to get the 3 ph to your VFD. Whenever your are powering up a VFD with single phase for a 3ph output the VFD will be derated in size therfore for a 7.5hp motor you would need like a 10 hp single phase VFD which are not typically sold. Most single phase VFD's only go up to 5Hp.

Hope this Helps,
JC Chamberlin III
Precison Electric Inc.

This link will get you to a good drive if you end up needing one:
http://cgi.ebay.com/AC-Tech-SMVecto...emQQptZLH_DefaultDomain_0?hash=item518cbda45a

Very easy to program.


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## nrp3 (Jan 24, 2009)

I ended up calling AC Tech directly and they spec'd a 20hp 230v unit that could accept 240v single phase input and would generate a 3 phase output of the same voltage. I will rewire the motor according to the diagram on the junction box for 230v and should be all set. I got the different parameters from the blender manufacturer so I can program the new VFD correctly. Now to put it all together. I guess I can see why some of the more experienced guys might think this was a no brainer. The customer service people at Ross and AC Tech were both very helpful.


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## John Valdes (May 17, 2007)

Electric_Light said:


> The blender manufacturer didn't intend it to be used in a place without 3 phase power. Aside from finding a 240v 1ph input VFD intended for driving a 3ph 480v motor of your size, you'll still need a rotary converter to provide 3ph.
> 
> Get the mfgr to get you the 208 or 240v VFD, then get a 230-1ph to 230-3ph rotary converter.


Silly advice. The manufacturer is not that stupid. 
A stock AC Tech VFD in this HP range will run on single phase input and output the same voltage in 3 phase.

The manufacturer has provided you with a solution on their dime. See if they will program the drive at the factory so all you have to do is reconnect the motor. How easy can that be?


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## Bob Badger (Apr 19, 2009)

John Valdes said:


> The manufacturer has provided you with a solution on their dime. See if they will program the drive at the factory so all you have to do is reconnect the motor. How easy can that be?


Great advice, go with the factory offering and you can't go wrong.


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## Electric_Light (Apr 6, 2010)

John Valdes said:


> Silly advice. The manufacturer is not that stupid.
> A stock AC Tech VFD in this HP range will run on single phase input and output the same voltage in 3 phase.
> 
> The manufacturer has provided you with a solution on their dime. See if they will program the drive at the factory so all you have to do is reconnect the motor. How easy can that be?


From what I read, the blender already has a 480v 3ph VFD on it, and the manufacturer offered to provide him with a 208v 3ph input VFD as an accommodation for a customer without 480v but has a 208 or 230v 3ph service.


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## nrp3 (Jan 24, 2009)

I have the new VFD and Ross gave me the parameters to change. Only five or so out of 99. No concerns with rotation, you can't damage it. I'll have to fab up some shallow strut to mount it as it taller and has fans so I need to raise it. The instructions for single phase hookup are right in the book, use L1 and L2. 

As for it really being designed for three phase/480v, I can buy into that. Instead of say four #10's in a 3/4 conduit or MC, I now have a piece of 1-3 MC AL due to the loss of phase and derate. It'll work, though not too pretty.

The blender mfg would send me a 208/230v VFD for free and it would work single phase I'm sure but you need to upsize if you are going to use single phase with the motor you have, so says AC tech. So we ended up buying an upsized unit.


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## John Valdes (May 17, 2007)

I did not realize you had a 15 HP blender motor. Yes, the manufacturer was correct to use a 20 hp in this case. One size up.
Thats some blender you got there.

I bet you will be much more careful in the future when ordering equipment.


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## nrp3 (Jan 24, 2009)

Actually, its only a 7.5 hp motor and maybe we could get away with the next lower size VFD, but when talking with AC Tech, it sounded like it was close, so I chose to go bigger. I told the customer to please call before buying any more equipment so I can plan for it. Its about 150 feet to the 200a panel. There are plenty of little subpanels but none I feel comfortable tying into. Its a pretty big blender.


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## John Valdes (May 17, 2007)

nrp3 said:


> Actually, its only a 7.5 hp motor and maybe we could get away with the next lower size VFD, but when talking with AC Tech, it sounded like it was close, so I chose to go bigger. I told the customer to please call before buying any more equipment so I can plan for it. Its about 150 feet to the 200a panel. There are plenty of little subpanels but none I feel comfortable tying into. Its a pretty big blender.


You only needed to go up to 10 HP. But that was their call. If I had to pay for it, I would have gone with a 10 HP either from them or someone else. But at least you are all set. Good luck. Wheres that AC Tech guy when you need him? :laughing:

One more thing. If that motor is over 100' from the drive, you should use a load reactor. There is a thread right here on the PLC/Drive section of this forum you can check out.


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## nrp3 (Jan 24, 2009)

The homerun is around 150' or so, both the machine and VFD are attached to the machine. The VFD is the operating control, on off etc. I was reading that thread and wondered if that was something else I needed.


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## MDShunk (Jan 7, 2007)

nrp3 said:


> The homerun is around 150' or so, both the machine and VFD are attached to the machine. The VFD is the operating control, on off etc. I was reading that thread and wondered if that was something else I needed.


No. If the VFD is pretty much on the motor, you don't need a load reactor. Some plants will centralize their VFD's for environmental reasons, or the production line is very long and they have the VFD's in a control cabinet. That puts a lot of distance between the VFD and the motor, which makes the load reactor a lot more useful. You can add one if you want to, but you won't really get any benefit from it. That would be wasteful.

If this blender ever gets integrated into an automated production line, that's when you'd probably start to think about adding a load reactor. In that case, that VFD will probably end up getting relocated to a control cabinet for the whole line.

I was in a paper filter manufacturing plant recently that had all their PLC's, VFD's, servers, etc installed in a little hut in the plant, since it was the only place that was air conditioned and free from paper dust.


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## nrp3 (Jan 24, 2009)

The housing for the VFD is NEMA 4 and it is dusty in that corner. They have some sort of dispenser for their products. Some of which are very fine powders. I bought a NEMA 4 disconnect to keep the dust out of the disconnect. Not sure its really a classified area, but I could see that dust getting in the switch.


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## nrp3 (Jan 24, 2009)

Hooked it up, changed the five parameters, and adjusted some limit switches to work right, seems to be fine. I don't know how to operate it or really how to adjust the speed, but the blender company rep is supposed to come by.


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