Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: PG1995 on 12/09/2017 00:34:02
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Hi,
Please have a look on the attachment. Could you please help me to understand the reason for introducing the factor of "1000" is introduced in eq. 4.4 and eq. 4.5? Thank you.
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The factor of 1000 come from the change from V to kV (1 kV = 1000 V)
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The factor of 1000 come from the change from V to kV (1 kV = 1000 V)
Thank you.
Eq. 4.4, Base current I_b = (1000)(MVA)_b/(kV) = (kVA)_b/(kV) A. It looks like as if "Mega" is converted into "kilo" by multiplying it by "1000" which doesn't make any sense. It looks like that 1000*Mega=kilo? Thanks.
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The factor of 1000 come from the change from V to kV (1 kV = 1000 V)
Thank you.
Eq. 4.4, Base current I_b = (1000)(MVA)_b/(kV) = (kVA)_b/(kV) A. It looks like as if "Mega" is converted into "kilo" by multiplying it by "1000" which doesn't make any sense. It looks like that 1000*Mega=kilo? Thanks.
Ah yes, you are right. On closer examination, it does appear that they multiplied by 1000 instead of dividing.
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This looks like a subject on power electronics?
You should learn to recognize relevant entries from the table of metric prefixes.
- M = Mega = 1 million = 106
- k = kilo = 1 thousand = 103
- These are often used for voltages and currents in power transmission lines
It is likely that you will also need to recognise smaller values as well:
- m = mili = 1/thousand = 10-3
- μ (or u) = micro = 1/million = 10-6
- n = nano = 1/billion = 10-9
- These are often used for capacitances and currents in low-power circuits
You should also become familiar with how to convert between the different prefixes; when to multiply or divide by 1000 or 1000000.
See: https://en.wikipedia.org/wiki/Metric_prefix
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I would add pico p = 10-12 Again useful for capacitance.
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Thank you, everyone!