15 Minute Tech Talk - 75 kVA Transformer
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- čas přidán 13. 08. 2020
- This session will look at a 75 kVA transformer and select primary / secondary OCPDs as well as primary and secondary transformer conductors.
For more information on Eaton dry-type low voltage transformers please see the following link:
www.eaton.com/us/en-us/produc... - Věda a technologie
As a newbie on learning about transformers I was a little confused about the formula you used. After re-reading my text and doing the calculation according to the text, I got approx values for primary and secondary current FLA. Happily, I realized that your formula is a shortcut and accurate (within an approx). I will use it in the future for swift calculations. Thx. Good video for newbies like me. Keep it up
Really like listening to this guy lay down some riffs
nice i just put in a 75 kva transformer and panelboard, it was a great tech talk
Hey Tom. Great job on these tech talks. Robert from Omaha
You got my attention, thanks for your time!
Glad I could help!
Incredibly informative video thank you
Glad you mentioned selective ampere selection. Retired from a large hospital/research center where they talked about this but never did antyhing on it. Several times a zone mechanic was replacing a 277 volt breaker and caused a short circuit where the 225 amp tripped and not the 20 amp branch circuit breaker. This occured in at least 3 large ( 10 to 14 floor ) buildings.
Really appreciate the feedback. I have often been told that events like what you described never occur in a hospital. Would love to learn more.
This happened to me at York University Campus .3 phase 600v/347V lighting control circuit rated for 20 amp single phase breaker took out the main 3 phase 100 amp lighting control breaker .Crazy stuff happens with impedance drops and AIR ratings of breakers .
Take an hour if you have to brother, great information like always.
Great video 👍👍
awesome video
Your sound is 👍
Thank you brotha, appreciate you!
Any time!
**Very good video !!
One of Eaton’s competitors makes 250 amp MCB and 250 amp buss panels as a standard for a good reason. Many times if 250 is specified, their competitors, like your company, couldn’t compete with the price. Economics pay a huge role in the decisions. Especially if you are the contractor and designer.
Thanks for joining in the discussion @kevinCoop1.
Thanks for the video. I have a 30 kva transformer. I need to feed 415vac to the input. I require 240vac at the output and not 120.how do i achieve that?
LOVE IT 😍🤩👍
What gauge wire did you use for high and low voltage?
Do you have troubleshooting videos for these transformers
Thanks
On the field we use 125% calculation for primary and secondary OCPD.
Thanks for this master class.
Sure thing. I agree that 125% is very common. I think a little depth of knowledge helps to understand the why's. You have to love those rules of thumb that get you through some hard parts.
Nice job Tom as usual. I thought you needed to supply ocpd to the load possible regardless...
Thanks Robert. Yea, that primary OCPD is tricky because you have that pesky little detail called inrush :)
So if I am installing a 75kva Step Up i can just use all the info you just provided but just flip info on primary and secondary ?
step up transformers are a little different beast. Make sure the transformer is listed for back feeding and as far as I can tell you make the same calculations. Inrush on that will be a little different too. I'll do some research and put a program together as this could be a good discussion on the program.
STANDARD PRACTICE IS WIRE FOR 125% IN CANADA FOR WIRE SIZE AND NOW SOME AREAS WANT OVERSIZED NEUTRAL .All because of harmonics from VFDs And Switch mode power supplies .Ztrap is optional
Thank you Carlu for that note. Very good point on oversizing the neutrals!
great job. however I would like to see the wiring process. thank you.
Hey Ronald. thanks for the feedback. I"ll see what I can do on the wiring. going to have to get a video on that in our experience center.
so can i run a 3phase cnc machine from 1phase power source using this type of transformer? thanks
That would take a bit more than just this transformer.
Thanks , you really know what you’re speaking ! Any and all advice is welcoming! “ My breaker box in my house is 100A / 120v 2 Phase - I’m installing for electrical back~up only a 5KVA Solar Inverter 230v charge controller 48v PWM what I see is the inverter 230v One Phase the L1 is 115v & the Neural is Hot line of 115v & the ground is a ground ! What’s you’re idea of using the L1 = 115v & the Neutral = 115v into a 20A Double Pole breaker to back-feed my breaker box all One Phase of 115v & the inverter at 5KVA is 86A and my house per month uses between 3-3,500KW a month and I’m going to use a SIEMENS Transformer MTO100A 480-220 input One Phase & Output 240-110 Two Phase ~ Off my Order inverter to the 20A Double Pole breaker . Sounds good ?
Wth are you talking about. Better call electrician
for the secondary time i would put 250 amps panel broad
Thanks for commenting and adding the value of the video. I agree with you. There are so many options in these applications.
Please I needed to do a house wiring of both 110v and 220v after it all it was 30 socket in number for the 110v and I want to know the type of the step down transformer to use in order to power the entire room.thank you
Why is the optimum ocpd 100amps and not 115A
sungkim1189, I would agree that a 115A OCPD would be the appropriate solution for that application.
115A is not a standard OCPD rating. Standard ratings are 100, 110, 125, and 150 amps. For 35 years, I used 125 amps on 75Kva rated primary.
.9 is the efficiency of the transformer
Thanks for commenting and adding to the value of the information!
x the equation i think u will mixt up people more than anything lol u should put all the numbers on the screen maybe it will help...maybe lol.
😜