Buck boost transformer question

[Tarzan]

I m qouting a tanning bed salon in which 8 tanning beds will are to opperate on 235 volt delta. Supply voltage will be 208/120 three phase with a delivery voltage of 214

Two buck boost as an autotransformer have a rating of 123.9K 312 load amps are capable of boosting 208 to 229 with a 450 amp fuse size.

Loads based on 235 three phase

5 16 amp 6,512 32,560
2 32 amp 13,024 24,048
1 56 amp 22,792 22,792

79,400 total load


With an imput load of 215 amps @ 214 and a secondary load of 195 @ 235

Using 450.4 Would the proper wiring method be

300 amp primary fuse on 4/0 copper terminating into a 225 amp main breaker 24 circuit panel, within 25 feet. With individual overcurrent devices and branch circuits to feed each bed.

I know this would be at best the minimum requirment. Looking forward to your suggestions

 

[bob]

I m qouting a tanning bed salon in which 8 tanning beds will are to opperate on 235 volt delta. Supply voltage will be 208/120 three phase with a delivery voltage of 214

Two buck boost as an autotransformer have a rating of 123.9K 312 load amps are capable of boosting 208 to 229 with a 450 amp fuse size.

Loads based on 235 three phase

5 16 amp 6,512 32,560
2 32 amp 13,024 24,048
1 56 amp 22,792 22,792

79,400 total load


With an imput load of 215 amps @ 214 and a secondary load of 195 @ 235

Using 450.4 Would the proper wiring method be

300 amp primary fuse on 4/0 copper terminating into a 225 amp main breaker 24 circuit panel, within 25 feet. With individual overcurrent devices and branch circuits to feed each bed.

I know this would be at best the minimum requirment. Looking forward to your suggestions

Your post says that you are using 2 transformers but you say the caculations are 3 phase. Which is it? I am not following your caculations.

Loads based on 235 three phase

5 beds at 16 amp x 235 = 18800
2 beds at 32 amp x 235 = 15040
1 bed at 56 amp x 235 = 13260
Total 47100

Amperage = 47100 kw/(235 x 1.73) = 116 amps if the load is balanced. Its not. The best you can do is

Phase .... A .... B ..... C
bed 1 .... 56 ... 56
bed 2 .... 32 .... 0 .... 32
bed 3 .... 0 ..... 16 ... 16
bed 4 .... 0 ..... 16 ... 16
bed 5 .... 0 ..... 16 ... 16
bed 6 .... 16 .... 0 .....16
bed 7 .... 0 ..... 16 ....16
bed 8 .... 16 .... 0 .....16
Total .. 120 .. 120 ....128

 

[iwire]

Bob only two buck boosts are needed for 3 phase delta

 

[Tarzan]

But are the calculations and the wiring methods correct?

 

[bob]

Iwire
Thanks for the info. I looked at Sola hevi Duty and they show 2 transformers
with 3 phase input. It is called open delta.

But are the calculations and the wiring methods correct?

Tarzan
I wish you would explain your load caculations. I may be reading you information wrong.
How do you get these figures?
Loads based on 235 three phase

5 16 amp 6,512 32,560
2 32 amp 13,024 24,048
1 56 amp 22,792 22,792

79,400 total load