Mind helping me on my math.

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AC\DC

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Customer requesting a New 400 amp service. He has two CNC machines he got. I posted about the Phase Converter https://forums.mikeholt.com/threads/cnc-machine-in-rotary-phase-conveter.2577835/

So this is a Residents ,He I putting the cnc in the garage and want another 200 amp panel. His load is quite large. One is

VF-2SSYT Pre-install Guide

Best in CNC Machining Value
www.haascnc.com www.haascnc.com

Specs say 22.4kw that just for motor so used Full load at 70 gets me at 27.885 kw
His others is Full load of 40 amps at 230 volt 3/0 is 15.934 kw at power factor of 1. None of these state what power factor they are at how should I go with that.

These are 3/0 equipments. There going to be running for more than 3 hours so 1.25 for each of them puts one at
27.885kw x1.25 = 34.85625 kw
15.934kw x1.25=19.9175 kw

Does the Rotary phase converter care about the 1.25 percent???

Either way with the unit he has, I am past he Max KW for his unit if he wants to run them both at the same time.
His unit is a Ad/ADX60, and is a 30KVA unit

That my first question.

Next what do I account for power loss on the phase converter????? is it not an issue to include in my load calc??
 

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The chart shows the optimal HP of 30 and Max of 60, with amps 84 & 168 respectively.
Use that and don't worry about the rest of the calculations.
Your customer needs to decide where, between optimal and max that he can operate taking into consideration that phase converters are not recommended to begin with.

Advantage being those CNCs will rarely see max load, especially not at the same time.
 
There was a Mathematician called Hall
Who had a hydronical ball
The cube of eight
Plus of fifth five eights
Of sod all.

Excuse my sense of humour................or not.
 
It is not uncommon to only get 60% to 80% of 3-phase motor horsepower when operated with a static phase converter.
 
Statements like that from machinery mfrs are what I call “CYA statements”, meaning they include them to give themselves cover for when you attempt to make a warranty claim after it fails to work. That’s because there are several different technologies that claim to be “phase converters”, some of which cause significant power loss, others can cause control system failure and they don’t want to be in a position to recommend one over another, so they just say “you are on your own”. Bottom line, complex highly expensive CNC machines are probably not the best choice for installing in a residential single phase service application, regardless of how many amps they have there.

But I know, that’s not your issue, it’s your problem to try to solve. Each machine will have a control panel and assuming these are UL listed, each control panel it’s required to have a visible nameplate stating the electrical power requirements. Often, since there are usually multiple motors inside, they will give this to you as a “Minimum Circuit Ampacity” (MCA) and a “Maximum Over Current Protection” (MOCP or just MOP if you consider overcurrent to be one word). Since they are in 3 phase values for a 3 phase machine, simply multiply those values by 1.732 to get the single phase values you need as the input to the phase converter.

Assuming you will be using a Rotary Phase Converter, they claim 95-97%% efficient AT BEST, but that is based on “laboratory controlled testing”, in reality it’s more like 85%. But commercial RPCs are usually sold by their OUTPUT capacity, meaning the connected 3 phase load. So if you select one based on that, then use the input current that they state on THAT nameplate, it gives you what you need.
 
Since you have to get a new service anyway and probably pay POCO for new transformer seems like two big 240V 3ph loads is the perfect situation for an open delta? Have you triple confirmed the POCO won't do a open delta? If they have two phases on the pole they can make a bank.
 
so reading up more on the phase converter. it bassicly converters this load to a high leg delta in reference to ground. I have not looking his machine and ill call the manufacture to make sure that high leg won't mess up with controls in the machine.
 
AC\DC said:
so reading up more on the phase converter. it bassicly converters this load to a high leg delta in reference to ground. I have not looking his machine and ill call the manufacture to make sure that high leg won't mess up with controls in the machine.
Click to expand...
Not quite.
AC\DC said:
The garage is attached to his home. Your idea would be good for only serving a separate garage. I need a neutral.
Click to expand...
An open Delta with a hi leg gives you a neutral. The instructions indicate this is an acceptable 3 phase for their equipment. Use it if at all possible.
 
Owner already bought everything.

I asked power company about the high leg open delta.Going to look more at that only seen a closed delta with high leg before.
The few articles I did read last night seems power company don't like open delta and are used for emergency issues
 
AC\DC said:
Owner already bought everything.

I asked power company about the high leg open delta.Going to look more at that only seen a closed delta with high leg before.
The few articles I did read last night seems power company don't like open delta and are used for emergency issues
Click to expand...
Open delta high leg including delta-breaker high leg, was common is some locations when A/C that needed three phases was first introduced to existing residences. Adding a single pot for the third phase was the simplest way for POCO to provide this service.
 
GoldDigger said:
Open delta high leg including delta-breaker high leg, was common is some locations when A/C that needed three phases was first introduced to existing residences. Adding a single pot for the third phase was the simplest way for POCO to provide this service.
Click to expand...
Delta breakers have not been allowed, or built, for almost 50 years.
Open delta, high leg, 4 wire systems are still available depending on your POCO.
 
Power company won’t do open delta says it messes with there system and would rather have a phase converter, seems worse with phase converter but o well.

for the 125 of largest motor would the phase converter be seen as largest motor? If so the it will be larger than a 200 amp disconnet. Or just use the largest of the two connected motors since they are the ones pulling the actual load.
 
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