running 480v machine on 380v

winnie said:
480V is a common generator voltage. If the generator is designed for 480V then there are no issues with this approach.

Does the generator have a 12 lead alternator? Different voltages are usually a combination of excitation change and alternator connection. In the systems I've worked with, excitation could adjust the coil voltage from 120V to 140V, then the coils would be connected differently to get 208V, 240V, 416V or 480V.

I would be concerned about the components outside of the alternator if they are not specifically designed for the higher voltage.

D
Click to expand...

Yes I think I will be able to find 12 leads alaterantor. That’s true .I have to concern about generator controller ,relays and contractor.


Sent from my iPhone using Tapatalk
 
Emad said:
Yes@tortuga
We are now using type L outlets and power system is 380/220v 50hz.
However,there are a little number of old Oil fields that they still use 220y110 ,whose I believe established by Amharic companies in early 1960s


Sent from my iPhone using Tapatalk
Click to expand...
Yes, that was my experience. I also used 11kV for some projects. Might have been specials,
 
Besoeker3 said:
Yes, that was my experience. I also used 11kV for some projects. Might have been specials,
Click to expand...

Yes ,many oil companies use 20kv 11kv and 6.6kv .
Also I think the National electricity Company use 11kv lines in distribution 11/0.38


Sent from my iPhone using Tapatalk
 
Emad said:
Yes I think I will be able to find 12 leads alaterantor. That’s true .I have to concern about generator controller ,relays and contractor.


Sent from my iPhone using Tapatalk
Click to expand...

I suspect that a standard generator with a 12 lead alternator will be rated for use up to 480V. But I agree, the issue is confirming you get a generator rated for the voltage.

Back in your original post, you said that the proper transformer was not available. I was wondering if you'd given any thought to my suggestion of using 2 or 3 standard single phase transformers to get your desired transformation ratio. What sort of single phase transformers can you easily get?

-Jonathan
 
winnie said:
I suspect that a standard generator with a 12 lead alternator will be rated for use up to 480V. But I agree, the issue is confirming you get a generator rated for the voltage.

Back in your original post, you said that the proper transformer was not available. I was wondering if you'd given any thought to my suggestion of using 2 or 3 standard single phase transformers to get your desired transformation ratio. What sort of single phase transformers can you easily get?

-Jonathan
Click to expand...

Single phase transformers with capacity larger than 5kva are not common here
All Workshops I reached here can do the rewinding only .
I found 3ph transformer 380/110c but with 30kva
Some body suggested to use it as open delta auto transformer ,but 30kva capacity is not sufficient


Sent from my iPhone using Tapatalk
 
Emad said:
Single phase transformers with capacity larger than 5kva are not common here
All Workshops I reached here can do the rewinding only .
I found 3ph transformer 380/110c but with 30kva
Some body suggested to use it as open delta auto transformer ,but 30kva capacity is not sufficient


Sent from my iPhone using Tapatalk
Click to expand...
1) Can you get 5 kVA 240:120V single phase transformers? Three such transformers in a wye boost configuration would give you about 41kVA of capacity at 570V.

2) Can you get 5 kVA 380:110V single phase transformers? Two such transformers in an open delta boost configuration would give you about 38.5 kVA of capacity at 490V. Three such transformers would in a sort of 'stretched delta' boost configuration would give you about 43.5 kVA of capacity at 553V

3) What is the full configuration of the 3 phase transformer that you've found, primary voltage, secondary voltage, and winding configuration (wye, delta, etc.). Can the workshops do things like reconnect the transformer winding terminations if necessary?

-Jonathan
 
Emad said:
Single phase transformers with capacity larger than 5kva are not common here
All Workshops I reached here can do the rewinding only .
I found 3ph transformer 380/110c but with 30kva
Some body suggested to use it as open delta auto transformer ,but 30kva capacity is not sufficient


Sent from my iPhone using Tapatalk
Click to expand...
Winnie covered it well. I was going to say that with autotransformers, you don't need to meet the full kVA of the equipment, on the rated amps times the difference in voltage.
 
winnie said:
1) Can you get 5 kVA 240:120V single phase transformers? Three such transformers in a wye boost configuration would give you about 41kVA of capacity at 570V.

2) Can you get 5 kVA 380:110V single phase transformers? Two such transformers in an open delta boost configuration would give you about 38.5 kVA of capacity at 490V. Three such transformers would in a sort of 'stretched delta' boost configuration would give you about 43.5 kVA of capacity at 553V

3) What is the full configuration of the 3 phase transformer that you've found, primary voltage, secondary voltage, and winding configuration (wye, delta, etc.). Can the workshops do things like reconnect the transformer winding terminations if necessary?

-Jonathan
Click to expand...

Thank you Jonathan
This can probably solve the problem .I can find all of these ranges
I hope if you can be more generous with me and teach me how you did the maths for the three cases
Also:
Do you mean by open delta to connect the primary of two phase in series with their secondaries and get the output across the two windings?
What about stretched delta ?
I should be very appreciative if I get any sketches


Sent from my iPhone using Tapatalk
 
You must log in or register to reply here.
Top