Need Help! Phase converter for a machine with several load changes: rotary or digital?

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    *Registered User* Ale88's Avatar
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    Question Phase converter for a machine with several load changes: rotary or digital?

    Hi guys,

    I'm gonna need a phase converter for a gelato machine, so it's gonna work with several load changes and it has two different motors. I wanted to know if I can get a digital phase converter (like Phase Perfect) or if in my case it's better a rotary PC.

    I read that the rotary PC would handle better all the different loads while the digital PC is better with static work, is it true?

    Of course I would prefer the digital PC because it makes no noise and it needs less space, but at the same time I want to be sure to get most suitable PC for my specific case.

    Oh, I have no experience at all in this stuff, I only did a research to know a little bit about it.

    Thanks!

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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Hi,
    what output power does your machine require?

    What is the voltage of the input power? Do you know the current rating of the fuse/circuit breaker on the input circuit?

    Craig



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    *Registered User* Ale88's Avatar
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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Hi Craig, please see the attachments for the machine and panel specs

    Attached Thumbnails Attached Thumbnails Phase converter for a machine with several load changes: rotary or digital?-gelato-machine-specs-jpg   Phase converter for a machine with several load changes: rotary or digital?-building-electrical-panel-jpg  


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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Hi,
    if I'm reading the pics correctly the machine has a peak power demand of 10.4kW.

    Your single phase input current, I assume 230vAC, will need to be 100A or more. That's a big ask.

    Do you have a utility connection that can deliver that sort of current?

    Craig



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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by joeavaerage View Post
    Your single phase input current, I assume 230vAC, will need to be 100A or more. That's a big ask.

    Do you have a utility connection that can deliver that sort of current?
    The building has 3 tenants, I'm one of them, and we have 400 amps in total to share. I'm the last who arrived so an electrical engineer did the calculations based on all our equipment + the highest demand in the last 12 months of the others 2 tenants (which are 11.89 kW and 16.89 kW) and the result is that the other two shops combined use a maximum of 188 amps, we should use 114 amps which makes a total of 302 amps out of 400, that's what he told us.



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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Hi,
    OK, that sounds like you've done your homework.

    In New Zealand 63A is the common rating of a single phase domestic supply. In industrial and commercial installations
    three phase supply is the norm.

    A phase converter of that size is beyond my experience. I can only guess that such a device would be expensive. Would it not be cheaper
    to have the supply company install a three phase supply?

    Craig



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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by joeavaerage View Post
    A phase converter of that size is beyond my experience. I can only guess that such a device would be expensive. Would it not be cheaper
    to have the supply company install a three phase supply?
    I already asked the prices of the phase converters, for the rotary it's about $3,000-3,500 while the digital $5,000 (based on the size I need of course), bringing the 3 phase would take months and at least $30,000. The landlord is already willing to pay half of the PC cost but I don't really think he's even gonna consider spending $30,000 (minimum). So the PC is definitely the simplest and cheaper solution



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    Community Moderator Jim Dawson's Avatar
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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Looks like a 20HP RCP would do just fine. Each motor you switch on in the system adds to the overall capacity, so if the drive motor is running and the compressor comes on, you get the benefit of both the drive motor and the RPC to start the compressor.

    Here is a 20 HP. I installed one of these for a customer a year or so ago, and it's working fine. Runs two CNC machines. https://www.ebay.com/itm/20hp-3-Phas...Sqw:rk:14:pf:0

    Jim Dawson
    Sandy, Oregon, USA


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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by Ale88 View Post
    Hi guys,

    I'm gonna need a phase converter for a gelato machine, so it's gonna work with several load changes and it has two different motors. I wanted to know if I can get a digital phase converter (like Phase Perfect) or if in my case it's better a rotary PC.

    I read that the rotary PC would handle better all the different loads while the digital PC is better with static work, is it true?

    Of course I would prefer the digital PC because it makes no noise and it needs less space, but at the same time I want to be sure to get most suitable PC for my specific case.

    Oh, I have no experience at all in this stuff, I only did a research to know a little bit about it.

    Thanks!
    Go with the Phase Perfect for the max supply you need they are very good and work better than any RPC will ever work they will tell you what size you will need for your equipment you have

    RPC are very inefficient and cost more to run than a Phase Perfect I have a 100A Phase Perfect and would never use anything else

    Mactec54


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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    In another forum I got this answer, what do you guys think?

    Rotarys going back at least 50 years have been doing the job and handling changing loads without problems.

    Contrary to salesman representations, digitals do NOT respond well to load changes. There are many references to this situation on machine tool sites, including the need to employ multiple digital converters on machines with multiple motor loads.
    The representation "the digital phase converters work just fine with multiple loads" is called puffery in polite terms when it comes from a salesman's mouth. Working just fine with a multiple load may be true under some circumstances, but it is not saying works fine with a multiple load that changes during the machine's use cycle.

    Your gelato machine has 2 very different loads on the mixer alone, evidently caused by different requirements to stir when mixing and then freezing. In addition your refrigeration compressor will be starting and stopping as well as probably absorbing an inconsistent amp draw during the chill period.
    That all adds up to a lot of load changes to the converter on every batch.

    A rotary easily compensates for load changes through momentum and additional draw on the single phase side.

    Solid state lacks the momentum feature so a computer must sense load and adjust electronics to accommodate it.
    If the frequency of output power MUST be maintained, solid state might be worth considering, but in your case it isn't a consideration, your loads are 100% motor.

    Your suggestion a solid state converter is quieter indicates you haven't had the opportunity to spend time around one. They emit everything from ultrasonic down to a whistle and generally drive dogs away.

    Were I in your position I'd buy track record and that is rotary.
    If you opt to go solid state insist on a written guarantee of fitness to the purpose of running your machine in your environment signed by a company officer and backed by a third party bond.




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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by mactec54 View Post
    I have a 100A Phase Perfect and would never use anything else
    With which kind of machine(s) do you use it? Single motor, multiple motors, no load changes, many load changes...?



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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by Ale88 View Post
    With which kind of machine(s) do you use it? Single motor, multiple motors, no load changes, many load changes...?
    60 Ton Boy Injection molding machine is the main machines I use it on, Heating and 30Hp motor which have continuous load changes plus material dryer mold heater compressor, this runs much more than you will ever need photo is of when I first installed this machine

    The Phase Perfect I have is probably the next size up from what you will need

    Attached Thumbnails Attached Thumbnails Phase converter for a machine with several load changes: rotary or digital?-molding-machine-jpg  
    Mactec54


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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by Ale88 View Post
    In another forum I got this answer, what do you guys think?

    Rotarys going back at least 50 years have been doing the job and handling changing loads without problems.

    Contrary to salesman representations, digitals do NOT respond well to load changes. There are many references to this situation on machine tool sites, including the need to employ multiple digital converters on machines with multiple motor loads.
    The representation "the digital phase converters work just fine with multiple loads" is called puffery in polite terms when it comes from a salesman's mouth. Working just fine with a multiple load may be true under some circumstances, but it is not saying works fine with a multiple load that changes during the machine's use cycle.

    Your gelato machine has 2 very different loads on the mixer alone, evidently caused by different requirements to stir when mixing and then freezing. In addition your refrigeration compressor will be starting and stopping as well as probably absorbing an inconsistent amp draw during the chill period.
    That all adds up to a lot of load changes to the converter on every batch.

    A rotary easily compensates for load changes through momentum and additional draw on the single phase side.

    Solid state lacks the momentum feature so a computer must sense load and adjust electronics to accommodate it.
    If the frequency of output power MUST be maintained, solid state might be worth considering, but in your case it isn't a consideration, your loads are 100% motor.

    Your suggestion a solid state converter is quieter indicates you haven't had the opportunity to spend time around one. They emit everything from ultrasonic down to a whistle and generally drive dogs away.

    Were I in your position I'd buy track record and that is rotary.
    If you opt to go solid state insist on a written guarantee of fitness to the purpose of running your machine in your environment signed by a company officer and backed by a third party bond.
    I'm always Amazed the things people post on these forums, most have not experience what's so ever with a Phase Perfect but still talk a load of BS about them

    With noise the only noise there is comes from the 2 fans that's for air circulation and only run automatically as needed for cooling

    They are not using a Phase Perfect then it they have any of these problems you list in your post

    Mactec54


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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by mactec54 View Post
    With noise the only noise there is comes from the 2 fans that's for air circulation and only run automatically as needed for cooling
    So in your opinion I could place the PP panel in a part of the shop with people passing by? It doesn't really bother the noise? Because I have to think also on the customer's side.



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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by Ale88 View Post
    So in your opinion I could place the PP panel in a part of the shop with people passing by? It doesn't really bother the noise? Because I have to think also on the customer's side.
    How much noise does the machine make this may be more than you will hear from the PP, I have mine mounted under the stairs there is a very low electrical noise that comes from the unit when the fans are not running, but being under the stairs you can't here that noise outside only the fans when they turn on and if nothing else is running in the shop, with my Haas mill turned on you can't hear the PP at all, the fans in the Haas electrical cabinet make more noise than the Phase Perfect, I know a Doctor that is using 2 of the largest PP to run a Imaging unit because they did not have 3Ph power in there building

    I had another though about your setup and most likely you could use 3 VFD Drives ( 1 ) for each motor this would be the cheapest way to do this and would cost no more than $2000 for 3 of the best VFD Drives money could buy, the rest of the control would be running on single phase so this would take care of the 3 ph part and the VFD Drives will run on the 240v single phase supply you have

    I would do it this way if the machine control can be configured to turn the VFD Drives ON/OFF because your motors are most likely set at one speed the VFD Drives can be controlled with just a relay to turn them ON / OFF

    Your machine may already have a VFD Drive of some kind in it, if so this can run on the 240v Single Phase supply you already have

    Last edited by mactec54; 10-21-2018 at 07:46 AM.
    Mactec54


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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by mactec54 View Post
    I had another though about your setup and most likely you could use 3 VFD Drives ( 1 ) for each motor this would be the cheapest way to do this and would cost no more than $2000 for 3 of the best VFD Drives money could buy, the rest of the control would be running on single phase so this would take care of the 3 ph part and the VFD Drives will run on the 240v single phase supply you have

    I would do it this way if the machine control can be configured to turn the VFD Drives ON/OFF because your motors are most likely set at one speed the VFD Drives can be controlled with just a relay to turn them ON / OFF

    Your machine may already have a VFD Drive of some kind in it, if so this can run on the 240v Single Phase supply you already have
    I don't know about that, I asked to the manufacturer and they told me they only use phase converters to run the machines when they don't have the 3 phase, and to be honest I don't wanna take any risk, it costed me a lot of money that machine, I prefer paying a few hundreds dollars more and being 100% sure it'll work.



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    Default Re: Phase converter for a machine with several load changes: rotary or digital?

    Quote Originally Posted by Ale88 View Post
    I don't know about that, I asked to the manufacturer and they told me they only use phase converters to run the machines when they don't have the 3 phase, and to be honest I don't wanna take any risk, it costed me a lot of money that machine, I prefer paying a few hundreds dollars more and being 100% sure it'll work.
    You are only running 3 electric motors this is the most inexpensive way to do it, the easy way is of course to buy the phase converter either way would work adding the VFD Drives would take someone that knows how to plain out the wiring this is very doable and would work just as well as any phase converter

    Your main motor if the speed is variable and is a regular AC Motor then it will already have a VFD Drive so you would only need ( 2 ) max $700 plus some rewiring, ask the manufacture what they are using for motor control

    Mactec54


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Phase converter for a machine with several load changes: rotary or digital?

Phase converter for a machine with several load changes: rotary or digital?