Can't stand the wait

[Kbeitz]

I bet your step down transformer is providing your neutral.

I just found about 480 2 yrs ago. How does it work without a neutral?

Most things that take the higher voltage does not take neutrals.
You only need it for 115 v things or control circuits .
Even then low voltage is made with transformers for control circuits .

[tmbrcruiser]

Sorry it's taken me until now to post pictures of the electrical system.

  

  

  

  

 

[ozarkgem]

very nice. Do you have a model and brand name of the 50 hp VFD? Sorry to keep bugging you but I am facing the same thing when I move my mill. Thinking I will have them set me a 480 transformer. We just need to see some sawdust.

[sandsawmill14]

Learning something new every day. I have worked with electric all my life
and I did not know you could get a 480 v single phase service instaled.
I googled it and it looks like most dont come with neutrals.

i have run across it a few times mostly in warehouses and such used to power the lighting i took a bunch 480 1 phase transformers out of a old factory one time and used a couple for lighting we never used it if we were installing new lights but some guys would order used light fixtures off of the internet and they would be 480v when they come in so i would just set a transformer and was good to go btw the transformers made a neutral but the 480 used 2 hot legs  the neutral to hot leg was 277v just the same as as standard 480/277 3ph setup

[tmbrcruiser]

Never bugging me we are all here to learn and help each other. The manufacturer is ABB, there are two VFD. The first runs the 50 hp motor on the mill and is model ACS550-U1 460V,NEMA 12, 1 Phase input, 124AMPS 3 Phase output@ 460V. The second runs the 15 hp on the blower and the same model with out put of 59AMPS 3 Phase @ 460V. Hope this helps you with your planning.

[ozarkgem]

Never bugging me we are all here to learn and help each other. The manufacturer is ABB, there are two VFD. The first runs the 50 hp motor on the mill and is model ACS550-U1 460V,NEMA 12, 1 Phase input, 124AMPS 3 Phase output@ 460V. The second runs the 15 hp on the blower and the same model with out put of 59AMPS 3 Phase @ 460V. Hope this helps you with your planning.

Thank you for the info. Did your electrician recommend the 50 HP VFD over a Rotary for the mill? I guess you have turned everything on and it works.

[sandsawmill14]

we have a 5hp motor running on one of those vfds and it does fine but we have the 30hp motor on a rpc  we cant make the load balance between the legs on the rpc for some reason i forget if it is a ph or c ph but b is generated by the rpc  and is the same as one leg but the other leg runs about 20amps higher than the other 2  but you cant use 480 with rpc it will only create a 3 rd leg not change the voltage  unless someone knows a trick they would like to share ??? you could do it transformers i guess but it would be alot more equipment

[ozarkgem]

we have a 5hp motor running on one of those vfds and it does fine but we have the 30hp motor on a rpc  we cant make the load balance between the legs on the rpc for some reason i forget if it is a ph or c ph but b is generated by the rpc  and is the same as one leg but the other leg runs about 20amps higher than the other 2  but you cant use 480 with rpc it will only create a 3 rd leg not change the voltage  unless someone knows a trick they would like to share ??? you could do it transformers i guess but it would be alot more equipment

JD'S electric in Joplin ,Mo builds 480v RPC's . I am going to stop and see him soon and will have more info. You will run your motor on 480 volt wiring. If your legs are not balanced you have to use run capacitors to balance out the legs. I know of a Baker 30 HP mill that runs on a RPC every day.

[sandsawmill14]

must be different from ours  ???  only one leg from the rpc goes to the disconnect and the other 2 are from the power company our rpc will produce 480 but its only on one leg the other 2 would still be 240 but again a transformer would probably do it but we only have 1 motor thats straight 480 all the rest are 240/480 so we just wired for 240 and used the vfd for the one oddball i am back at the tk mill this week but maybe i can go by the s&w mill in a day or 2 and try to get a pic btw we only have 120/240 1ph available at the s&w site just like whats in a house

[ozarkgem]

must be different from ours  ???  only one leg from the rpc goes to the disconnect and the other 2 are from the power company our rpc will produce 480 but its only on one leg the other 2 would still be 240 but again a transformer would probably do it but we only have 1 motor thats straight 480 all the rest are 240/480 so we just wired for 240 and used the vfd for the one oddball i am back at the tk mill this week but maybe i can go by the s&w mill in a day or 2 and try to get a pic btw we only have 120/240 1ph available at the s&w site just like whats in a house

I am confused on you setup. How do you get 480 on one leg?  I have the 240 from the power company 240 v single phase going into my RPC and 3 wires coming out. That is the 3 phase I just ran it to a 3 phase breaker box and began wiring. It is a 20 HP RPC.

[ozarkgem]

here are some pic of my RPC. The black wire on the right top is the single phase going in and the one on the left is the 3 phase going to the breaker box

  

 

[tmbrcruiser]

The original plan was rotary phase converter and cut wood. The first problem was a demand by the power company to use a soft start on the 50 hp motor. Problem being the rotary phase converter would generate full power immediately and the soft start would not consume this power, hence burned up converter. This why the VFD came to be the best way for me.

[Kbeitz]

You can make a soft start by using a pony motor.