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How to calculate the power transformer capacity
PUBLISHER:Shanghai Moye Electric Co.,Ltd¡¡RELEASE TIME:2017/7/13
The power of the transformer is determined by the load, both P2 = U2II2I + U2III2II + ... + U2nI2In (VA) P1 = P2 / ¦Ç (VA)
Where: P2 transformer secondary power calculation. P1 low-level power calculation value of the transformer.
U2I and U2II ... transformer secondary winding voltage (V), the value determined by the load.
I2I and I2II ... transformer secondary winding current (A), the value determined by the load.
¦§ is efficiency
Transformer capacity 1KVA The following transformer capacity is small, the efficiency is low, generally desirable ¦Ç = 0.8 to 0.9, for the transformer capacity below 100VA, ¦Ç select the small value; Transformer capacity in the 100VA to 1000VA are selected large value. ¦§ optional 0.7.
I1 = P1 / U1 (1.1 to 1.2) (A) where: U1 is the low voltage (V)
1.1 to 1.2 is the empirical coefficient taking into account the no-load excitation current.
Power transformer capacity is apparent power S = 1.732 ¡Á U ¡Á I, where s is the apparent power, U is the line voltage, I is the line current. Because there is a sensible and capacitive load, the power factor of the line can not be 1, so P = S ¡Á 0.8, p is the active power, 0.8 is the assumed power factor. 4500 ¡Â 0.8 = 5625, so the need for 5625KW transformer, but the transformer is a capacity of the division, it is impossible based on the results you calculated to your own manufacturing, so only select the capacity level of 6300KVA, KVA is the power of the unit, KW is the unit of active power.
Here also give you an example:
Transformer capacity efficiency is generally 0.8 or so, 500 ¡Á 0.8 = 400 (KW) load power factor of 0.8, 500KVA transformer can load 400KW power, power factor increases, the corresponding increase in transformer load power. Power factor increased from 0.7 to 0.95, per KW power to compensate the capacitance of 0.691 thousand, then: 500 ¡Á 0.691 ¡Ö 346 kilowatts (Kvar)
Where: P2 transformer secondary power calculation. P1 low-level power calculation value of the transformer.
U2I and U2II ... transformer secondary winding voltage (V), the value determined by the load.
I2I and I2II ... transformer secondary winding current (A), the value determined by the load.
¦§ is efficiency
Transformer capacity 1KVA The following transformer capacity is small, the efficiency is low, generally desirable ¦Ç = 0.8 to 0.9, for the transformer capacity below 100VA, ¦Ç select the small value; Transformer capacity in the 100VA to 1000VA are selected large value. ¦§ optional 0.7.
I1 = P1 / U1 (1.1 to 1.2) (A) where: U1 is the low voltage (V)
1.1 to 1.2 is the empirical coefficient taking into account the no-load excitation current.
Power transformer capacity is apparent power S = 1.732 ¡Á U ¡Á I, where s is the apparent power, U is the line voltage, I is the line current. Because there is a sensible and capacitive load, the power factor of the line can not be 1, so P = S ¡Á 0.8, p is the active power, 0.8 is the assumed power factor. 4500 ¡Â 0.8 = 5625, so the need for 5625KW transformer, but the transformer is a capacity of the division, it is impossible based on the results you calculated to your own manufacturing, so only select the capacity level of 6300KVA, KVA is the power of the unit, KW is the unit of active power.
Here also give you an example:
Transformer capacity efficiency is generally 0.8 or so, 500 ¡Á 0.8 = 400 (KW) load power factor of 0.8, 500KVA transformer can load 400KW power, power factor increases, the corresponding increase in transformer load power. Power factor increased from 0.7 to 0.95, per KW power to compensate the capacitance of 0.691 thousand, then: 500 ¡Á 0.691 ¡Ö 346 kilowatts (Kvar)