Step up current transformer 460 top 575V
Step up current transformer 460 top 575V
(OP)
Based on available funds we are looking on to ways to increase the existing plant line voltage 460V to 575V for some test we need to make.
From what I've learned is that even though higher voltage means lower amp requirements the existing power supply still will have only the original 200 amp service unless I bring in an additional supply.
We've been quoted a step up current transformer to allow us to connect to our 460V supply and give us 575V outvoltage for those test requiring such voltage. However I'm still limited to my existing 200 amp box. Can anyone tell me how big a motor I can test @ 575V with a 200 amp box?
From what I've learned is that even though higher voltage means lower amp requirements the existing power supply still will have only the original 200 amp service unless I bring in an additional supply.
We've been quoted a step up current transformer to allow us to connect to our 460V supply and give us 575V outvoltage for those test requiring such voltage. However I'm still limited to my existing 200 amp box. Can anyone tell me how big a motor I can test @ 575V with a 200 amp box?
Wayne E. Lovison
service-parts@naglepumps.com






RE: Step up current transformer 460 top 575V
Wayne E. Lovison
service-parts@naglepumps.com
RE: Step up current transformer 460 top 575V
In the US, it’s normal to limit loading on fuses or circuit breakers to 80% of rated. {Flame as desired.} ~150hp approaching continuous with full load (~200hp for shorter runs.) Unloaded—try it out—possibly ~600hp.
N.B.; during testing you may have to disconnect other building loads if 200A is the service-entrance rating.
Another consideration—a 3ø autotransformer in a boost {480>600V} arrangement can also be used to buck. {600>480V} It may be worthwhile to initially size them accordingly. For 200 amp capability—possibly:
Two well-ventilated approximately 25kVA 115°C-rise 480:120V dry-types
VERIFY Before You BUY!!
RE: Step up current transformer 460 top 575V
Remember higher voltage does not mean lower current. At least in the context I think you are referring too, motors. That rule can be applied to transformers though, higher voltage out means lower current out.
RE: Step up current transformer 460 top 575V
Let's see if I got this right. We have a 460V system and a 200 amp service. I want to test 575V motor's through a 460V/575V transformer. Should I get a transformer that is rated 600V and would this be more benefical?
Regardless I think both of you are telling me that regardless of the voltage I only have a 200 amp service regardless is that correct?
Does the rule apply that I can run a motor +/- 5% of its nameplated voltage without getting into trouble?
I think that is what busbar was trying to tell me in his comment. Advise if I should go for a 575V transformer or a 600V transformer. Money can't be too much difference and running at the higher voltage would lower the amp draw requirements (if I read you right above?).
Wayne E. Lovison
service-parts@naglepumps.com
RE: Step up current transformer 460 top 575V
You can run the motor at +-10% of rated voltage and not cause problems, if the motor is sized correctly.
As far as selecting the transformer, well thats a loaded question. If you run the motor at 600 volts then it may draw more current than operating at 575 volt. It should draw more current at 5% above nameplate or thereabouts. This is a strong misconception about sq cage motors, reduced or higher voltage does not mean lower current. Lower voltage means higher current for motors and as you get about 5% above nameplate volts then the current will also increase. If your operating between nameplate volts and 5% above nameplate volts then yes the current will generally be slightly lower than operating at nameplate voltage.
If your voltage coming in tends to be on the low side, then go with the 600 volt transformer. If it is on the high side then go with the 575 volt transformer. Just remember the ratios: If you have 460 coming in and have 575 coming out then the ratio is 575/460 (1.25) and the current is reduced to 460/575 (0.8 or 80 % of original value or in your case 80% of 200amps)
RE: Step up current transformer 460 top 575V
You can run the motor at +-10% of rated voltage and not cause problems, if the motor is sized correctly.
As far as selecting the transformer, well thats a loaded question. If you run the motor at 600 volts then it may draw more current than operating at 575 volt. It should draw more current at 5% above nameplate or thereabouts. This is a strong misconception about sq cage motors, reduced or higher voltage does not mean lower current. Lower voltage means higher current for motors and as you get about 5% above nameplate volts then the current will also increase. If your operating between nameplate volts and 5% above nameplate volts then yes the current will generally be slightly lower than operating at nameplate voltage.
If your voltage coming in tends to be on the low side, then go with the 600 volt transformer. If it is on the high side then go with the 575 volt transformer. Just remember the ratios: If you have 460 coming in and have 575 coming out then the ratio is 575/460 (1.25) and the current is reduced to 460/575 (0.8 or 80 % of original value or in your case 80% of 200amps).
See my FAQ
RE: Step up current transformer 460 top 575V
RE: Step up current transformer 460 top 575V
The numbers 480 and 600 are termed service voltage, and components that serve load devices generally have this rating, like transformers, breakers and starters.
A system of 200 amps at 480V 3ø corresponds to a maximum capability of 166kVA, and 200 amps at 600V 3ø corresponds to a maximum of 208kVA. Generally, this is the advantage of higher distribution voltage, but of course there are tradeoffs. For higher voltage, the most obvious concern is that more insulation is needed to isolate ø-ø and ø-ground conductive surfaces. So 480V versus 600V is a ‘regional preference,’ and if you use one it’s likely that your neighbor does too. Generally in the US, 480V is probably more common. In Canada, 600V is used most often.
Voltage limits are in a sort of ‘treaty’ agreed upon by folks like electric utilities and appliance/equipment producers, and published and promoted by ANSI (or CSA to the north.)
The agreed-upon limits for 480V systems are usually 440-504V and for 600V it’s 550-630V. {Note that 460 and 575 fall within this range.} So the percentage limits are close to +5% -8%. Generally equipment won’t necessarily work most efficiently in the extremes, but it’s not supposed to be damaged either.
Transformers can be described as constant-power devices. For a given kVA, [kilovoltamperes] there is a corresponding ratio of voltage and current. 200 amps at 480V 3ø is about 166kVA, which in turn is equal to 160 amps in a 600V 3ø circuit. Roughly 1 hp = 1 kVA.
RE: Step up current transformer 460 top 575V
I won't pretend to tell you I totally understand the logic but I do understand the precautions and can therefore ask better questions.
Thanks Again.
Wayne E. Lovison
service-parts@naglepumps.com