# help size Transformer/panel. thx



## 460 Delta (May 9, 2018)

It would help to know more about the machine, is it motor load, resistive load, a combination? 
75kva should be the transformer size. Likely delta-delta. 
Is the machine straight voltage, not field convertible to a lower voltage?


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## Ctsparky93 (Sep 17, 2016)

Soo what loads does that panel have? You will be putting a load of about 80 amps when the equipment is running at 240 side. And 300 amps on start up. Is this a sub panel or the service for the building? What is the FLA of the equipment? If it’s the service might be time to upgrade 


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## Ctsparky93 (Sep 17, 2016)

Also I would get a 240v delta to 480v wye step up transformer. And don’t use the grounded conductor if not needed. So you won’t have to worry about ground fault detectors. 


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## wildleg (Apr 12, 2009)

unless these machines are set up not to run at same time, you don't have enough power, unless I am misreading and by 3 wire you are saying that they are single phase ?. perhaps more info would help.

also, I assume startup is not considered continuous, I come up with 80a @480 ?


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## Ctsparky93 (Sep 17, 2016)

Since he said 480v 3 wire made me think he needs 480v 3 phase for the equipment. 


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## fab24hdumans (Nov 14, 2018)

*thank you for your help.*



460 Delta said:


> It would help to know more about the machine, is it motor load, resistive load, a combination?
> 75kva should be the transformer size. Likely delta-delta.
> Is the machine straight voltage, not field convertible to a lower voltage?


So the machines are called BTU (oven)(look like an enclosed 15 feet conveyor that shower some chemical and cook circuit board) and the 2 Units will be used at the same time. Yes, They have some little transformers inside so I suspect some field convertible lower voltage.

The only information I have is they need 2 BTU (oven), the spreadsheet said
" 480 3ph/3 wire (STD)- startup Power 65kw (inrush I guess?) and Operating Power 14-17 Kw.

I can ask tomorrow about motor load or resistive/combination...

Again, thank you for your help.


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## fab24hdumans (Nov 14, 2018)

So the machines are called BTU (oven)(look like an enclosed 15 feet conveyor that shower some chemical and cook circuit board) and the 2 Units will be used at the same time. Yes, They have some little transformers inside so I suspect some field convertible lower voltage.

The only information I have so far is they need 2 BTU (oven), the spreadsheet said
" 480 3ph/3 wire (STD)- startup Power 65kw (inrush I guess?) and Operating Power 14-17 Kw.

I can ask tomorrow about motor load or resistive/combination...

thank you for your interest


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## MikeFL (Apr 16, 2016)

You need model numbers on those machines.


Startup could be 15 minutes to get up to temperature if it's resistive load. There will be small motor loads if it's what I think it is, but someone's spending lots of money, so let's know and not think.


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## fab24hdumans (Nov 14, 2018)

Ctsparky93 said:


> Soo what loads does that panel have? You will be putting a load of about 80 amps when the equipment is running at 240 side. And 300 amps on start up. Is this a sub panel or the service for the building? What is the FLA of the equipment? If it’s the service might be time to upgrade
> 
> 
> Sent from my iPhone using Tapatalk


So the 240v panel (use as primary for this job) is 200 amp, with pretty much no load on it (maybe max 30 amp) for cubicle power.


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## fab24hdumans (Nov 14, 2018)

fab24hdumans said:


> So the 240v panel (use as primary for this job) is 200 amp, with pretty much no load on it (maybe max 30 amp) for cubicle power. It's just a panel from the distribution panels.
> 
> thank you.


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## fab24hdumans (Nov 14, 2018)

*you got it right.*



MikeFL said:


> You need model numbers on those machines.
> 
> 
> Startup could be 15 minutes to get up to temperature if it's resistive load. There will be small motor loads if it's what I think it is, but someone's spending lots of money, so let's know and not think.


those machines need to warm up about 15 minutes so yes Resistive load make sense, I will ask full info tomorrow about FLA and model numbers... I can't get this one wrong, those machines are big money.. :vs_OMG:

I appreciate your time guys.


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## fab24hdumans (Nov 14, 2018)

fab24hdumans said:


> So the machines are called BTU* (oven)(look like an enclosed 15 feet conveyor that shower some chemical and cook circuit board) and the 2 Units will be used at the same time. Yes, They have some little transformers inside so I suspect some field convertible lower voltage.
> 
> The only information I have is they need 2 BTU (oven), the spreadsheet said
> " 480 3ph/3 wire (STD)- startup Power 65kw (inrush I guess?) and Operating Power 14-17 Kw.
> ...


*[BTU Pyramax Convection Reflow Oven] on YOUTUBE.


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## fab24hdumans (Nov 14, 2018)

MikeFL said:


> You need model numbers on those machines.
> 
> 
> Startup could be 15 minutes to get up to temperature if it's resistive load. There will be small motor loads if it's what I think it is, but someone's spending lots of money, so let's know and not think.


the model is: 
BTU Pyramax Convection Reflow Oven. Seen on YOUTUBE.

thx


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## fab24hdumans (Nov 14, 2018)

MikeFL said:


> You need model numbers on those machines.
> 
> 
> Startup could be 15 minutes to get up to temperature if it's resistive load. There will be small motor loads if it's what I think it is, but someone's spending lots of money, so let's know and not think.





fab24hdumans said:


> the model is:
> BTU Pyramax Convection Reflow Oven. Seen on YOUTUBE.
> 
> thx





fab24hdumans said:


> So the machines are called BTU (oven)(look like an enclosed 15 feet conveyor that shower some chemical and cook circuit board) and the 2 Units will be used at the same time. Yes, They have some little transformers inside so I suspect some field convertible lower voltage.
> 
> The only information I have is they need 2 BTU (oven), the spreadsheet said
> " 480 3ph/3 wire (STD)- startup Power 65kw (inrush I guess?) and Operating Power 14-17 Kw.
> ...


ADD ON is the model of machinery---->BTU Pyramax 100 Convection Reflow Oven.


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## Ctsparky93 (Sep 17, 2016)

fab24hdumans said:


> the model is:
> 
> BTU Pyramax Convection Reflow Oven. Seen on YOUTUBE.
> 
> ...




So I found a video of a unit it showed the specs of the unit at 208v amps were 215. sounds like you need a service upgrade even if start up is 15 mins at 300 amps on 240 you got problems


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## telsa (May 22, 2015)

Reflow ovens are High Tech... used for wave soldering of circuit boards... especially required for surface mounted electronics.

For production runs, that is not laboratory scale projects, you'll want PLENTY of reserve power.

For the next thing you know, the client will want to ramp up production.

Such projects usually pass through the hands of EEs experienced with such systems.

Good luck.

Pilot production// laboratory scale runs are another matter. 

Don't assume that such folks are going to be any less fussy.


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## fab24hdumans (Nov 14, 2018)

Ctsparky93 said:


> So I found a video of a unit it showed the specs of the unit at 208v amps were 215. sounds like you need a service upgrade even if start up is 15 mins at 300 amps on 240 you got problems
> 
> 
> Sent from my iPhone using Tapatalk


We won’t use the 240volt to feed the tool, I will go with a Xfrm (step up) to get 480volt. At 480 volt, the tool need 100 amp. I just need to know the size Xfrm and panel to sustain the STARTUP (65kw resistive load) of 2 machines AT 480 VOLT.

Thank you


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## fab24hdumans (Nov 14, 2018)

fab24hdumans said:


> We won’t use the 240volt to feed the tool, I will go with a Xfrm (step up) to get 480volt. At 480 volt, the tool need 100 amp. I just need to know the size Xfrm and panel to sustain the STARTUP (65kw resistive load) of 2 machines AT 480 VOLT.
> 
> Thank you


240v 3phase 4wire—-> Xfrm ——> 480v 3phase 4wire
DELTA PRIMARY WYE SECONDARY


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## fab24hdumans (Nov 14, 2018)

fab24hdumans said:


> We won’t use the 240volt to feed the tool, I will go with a Xfrm (step up) to get 480volt. At 480 volt, the tool need 100 amp. I just need to know the size Xfrm and panel to sustain the STARTUP (65kw resistive load) of 2 machines AT 480 VOLT.
> 
> Thank you





telsa said:


> Reflow ovens are High Tech... used for wave soldering of circuit boards... especially required for surface mounted electronics.
> 
> For production runs, that is not laboratory scale projects, you'll want PLENTY of reserve power.
> 
> ...


This doesn’t require any EE experienced, nothing tricky here. I installed the same system for the same client 8 years ago but in a newer building where 480v WYE was available. The units at the time were smaller only 75 amps. 

Anyway thank you for your advice.


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## fab24hdumans (Nov 14, 2018)

EACH UNIT need 100 amps breakers 3phase, 480v. ABC phases run 90 amp each.


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## wildleg (Apr 12, 2009)

200x240x1.73=83040

does that tell you anything ? (how many times does 65 go into 83 ?)


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## MikeFL (Apr 16, 2016)

I agree there's nothing special about it. A reflow oven is a big pizza oven. Much cleaner though.


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## fab24hdumans (Nov 14, 2018)

MikeFL said:


> I agree there's nothing special about it. A reflow oven is a big pizza oven. Much cleaner though.


My opinion is I don’t have enough power on the PRIMARY panel 200 amp Delta (120/240 [208v high leg] to step up 480v 225amp panel.


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## glen1971 (Oct 10, 2012)

Curious why out of 24 posts, 14 are from the OP, including a couple quoting themselves? It's almost like they are talking to themselves.. lol..


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## MikeFL (Apr 16, 2016)

glen1971 said:


> Curious why out of 24 posts, 14 are from the OP, including a couple quoting themselves? It's almost like they are talking to themselves.. lol..



As much as technology has gone to hell in a hand basket nothing surprises me these days. All this was figured out 20 years ago but they keep adding stalking tracking for this and sell your mother's private parts for that to the point the content is 1% of the resources requisite to do what you want to do giving them 99% of your now quad core resources and they still over bloat everything to the point it doesn't work. wtf



/rant!


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## frenchelectrican (Mar 15, 2007)

fab24hdumans said:


> My opinion is I don’t have enough power on the PRIMARY panel 200 amp Delta (120/240 [208v high leg] to step up 480v 225amp panel.


If you say ya got a exsting 200 amp 240 volt delta then you are SOL cuz the KW rating of those big arse oven will pretty much knock your exsting service out aka a good chance you may trip the main breaker when ya fire it up. 

I would talk to POCO to see if they can change the service size to 400 or 600 amp 480 delta or wye service then it will handle the load very nice.

then you can use a conventail downstep transformer to 208Y120 or 240D120 volts either way will work just fine.


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## Wiresmith (Feb 9, 2013)

460 Delta said:


> It would help to know more about the machine, is it motor load, resistive load, a combination?
> 75kva should be the transformer size. Likely delta-delta.
> Is the machine straight voltage, not field convertible to a lower voltage?


whats the thought on the question of whether inductive or resistive load? inrush?


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## MikeFL (Apr 16, 2016)

It's a toaster oven with a moving belt running through it.


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## JRaef (Mar 23, 2009)

The moving belt likely has a VFD on it now, you will want a Wye secondary on the 480V side. VFDs need a grounded Wye source.



Ctsparky93 said:


> So I found a video of a unit it showed the specs of the unit at 208v amps were 215. sounds like you need a service upgrade even if start up is 15 mins at 300 amps on 240 you got problems





fab24hdumans said:


> We won’t use the 240volt to feed the tool, I will go with a Xfrm (step up) to get 480volt. At 480 volt, the tool need 100 amp. I just need to know the size Xfrm and panel to sustain the STARTUP (65kw resistive load) of 2 machines AT 480 VOLT.
> 
> Thank you





fab24hdumans said:


> 240v 3phase 4wire—-> Xfrm ——> 480v 3phase 4wire
> DELTA PRIMARY WYE SECONDARY



But IT DOESN'T MATTER that you only have 100A on the 480V side (secondary), if you feed it from the 240V service. It STILL equates to double that on the 240V side. If it's a 200A main breaker, your continuous load limit is 160A (80%). So even your RUNNING amps at 240V will be 180A, that's already over the entire capacity of your service right there, and no room for the "start up"current at all. So Ctsparky is right...


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## MikeFL (Apr 16, 2016)

The speed of the belt is indeed adjustable. 

My three phase reflow oven has three temperature zones plus belt speed setting in the profile setup.
Each build of something we manufacture has its own profile depending on the mass density and physical properties of what's going through the oven which is where the belt speed variability comes into play.
It's an art to get the thermocouples to produce a result with a temperature rate of rise while moving along the belt between 1C and 3C per second ramp up, the magnitude and duration of wet time and finally the cooling zone.

It is indeed on a wye service.
But that's my place and it's already built.


I've looked back through your thread and looked on the manufacturer's website (and watched the video). All that information is garbage regurgitated by the marketing department (not a surprise).


You said in an earlier post 65kW and you though that was inrush. It's not. 



You also said continuous but IIRC NEC definition of a continuous load is >3 hours. EC's on here can confirm this. That startup period is about 15 minutes depending on ambient conditions and profile settings. In reality it's about 10 minutes.


You also said "the spreadsheet said...". I don't know whose spreadsheet you're looking at, but you need manufacturer's data. You can't screw this up.


So my advice is get in touch with the manufacturer. They will have information you need to do this the proper way. Tell them you're the EC doing design/ build for a service for 2 of their ovens. They'll love to hear it and they'll give you good support. 



Or ask the author of the spreadsheet for the source of their information.


When you have good information come back and present it so we can work through it with you.


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## Ctsparky93 (Sep 17, 2016)

fab24hdumans said:


> My opinion is I don’t have enough power on the PRIMARY panel 200 amp Delta (120/240 [208v high leg] to step up 480v 225amp panel.




Lol that is what I was trying to say for a couple post. But I like your opinion. Well no it’s not a opinion it’s a fact. Btw basic ohms law with a multiplier of 1.732 for 3 phase tells you all you need to know. That this won’t work


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## telsa (May 22, 2015)

Production reflow ovens are power pigs, no doubt about that.


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## micromind (Aug 11, 2007)

If the requirements we were given are correct, there is barely enough energy available at the service to operate one of them, not both. 

Also, as noted, if there is a VFD involved, the 480 needs to be a 277/480 solidly grounded Y.


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## micromind (Aug 11, 2007)

frenchelectrican said:


> If you say ya got a exsting 200 amp 240 volt delta then you are SOL cuz the KW rating of those big arse oven will pretty much knock your exsting service out aka a good chance you may trip the main breaker when ya fire it up.
> 
> I would talk to POCO to see if they can change the service size to 400 or 600 amp 480 delta or wye service then it will handle the load very nice.
> 
> then you can use a conventail downstep transformer to 208Y120 or 240D120 volts either way will work just fine.


This is the best way to go. Make sure it is a 277/480 Y.


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## micromind (Aug 11, 2007)

fab24hdumans said:


> My opinion is I don’t have enough power on the PRIMARY panel 200 amp Delta (120/240 [208v high leg] to step up 480v 225amp panel.


The full 200 amps at 240 will yield 100 amps at 277/480 using a transformer that is 240∆ - 277/480Y.


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