Post History
If I connect this to a 12V supply and expose it to 10us pulse: 12V*10us/475uH = 252mA $$$$ This current flows in the primary magnetization inductance (475 μH) after applying 12 volts for 10 μ...
Answer
#3: Post edited
by
Andy aka
·
2020-12-17T10:38:50Z (about 4 years ago)
- > _If I connect this to a 12V supply and expose it to 10us pulse: 12V*10us/475uH = 252mA_
- $$$$
This is the current that flows in the primary magnetization inductance (475 μH) after applying 12 volts for 10 μs. This causes core saturation based on the volt-second figure limit of 11 volt-μs.- $$\dfrac{V\cdot dt}{L} = dI$$
- The 350 mA AC figure relates to load currents - this is unrelated to the magnetization current. Load current doesn't cause magnetization hence it can't create core saturation. This is because load current primary ampere-turns are cancelled entirely by load current secondary ampere-turns.
- $$$$
- 350 mA RMS is the primary load current limit and, given that the transformer steps down voltage by 2:1, the secondary load current limit is 700 mA RMS.
- > _If I connect this to a 12V supply and expose it to 10us pulse: 12V*10us/475uH = 252mA_
- $$$$
- This current flows in the primary magnetization inductance (475 μH) after applying 12 volts for 10 μs. This causes core saturation based on the volt-second figure limit of 11 volt-μs.
- $$\dfrac{V\cdot dt}{L} = dI$$
- $$$$
- I believe when the data sheet states the 475 μH figure, it relates to primary inductance despite them calling it \$L_S\$. If you have any doubts about this, then contact WURTH electronics for clarification. It does look like an error because primary inductance is the driven winding and it is solely responsible for core saturation.
- $$$$
- The 350 mA AC figure relates to load currents - this is unrelated to the magnetization current. Load current doesn't cause magnetization hence it can't create core saturation. This is because load current primary ampere-turns are cancelled entirely by load current secondary ampere-turns.
- $$$$
- 350 mA RMS is the primary load current limit and, given that the transformer steps down voltage by 2:1, the secondary load current limit is 700 mA RMS.
#2: Post edited
by
Andy aka
·
2020-12-17T10:33:53Z (about 4 years ago)
- > _If I connect this to a 12V supply and expose it to 10us pulse: 12V*10us/475uH = 252mA_
This is the current that flows in the primary magnetization inductance (475 μH) after applying 12 volts for 10 μs. This causes the core to saturate based on the volt-second figure limit of 11 volt-μs.- $$\dfrac{V\cdot dt}{L} = dI$$
The 350 mA AC figure will relate to the load current - this is unrelated to the magnetization current. Load current doesn't cause magnetization hence it can't create core saturation. This is because load current primary ampere-turns are cancelled entirely by load current secondary ampere-turns.
- > _If I connect this to a 12V supply and expose it to 10us pulse: 12V*10us/475uH = 252mA_
- $$$$
- This is the current that flows in the primary magnetization inductance (475 μH) after applying 12 volts for 10 μs. This causes core saturation based on the volt-second figure limit of 11 volt-μs.
- $$\dfrac{V\cdot dt}{L} = dI$$
- The 350 mA AC figure relates to load currents - this is unrelated to the magnetization current. Load current doesn't cause magnetization hence it can't create core saturation. This is because load current primary ampere-turns are cancelled entirely by load current secondary ampere-turns.
- $$$$
- 350 mA RMS is the primary load current limit and, given that the transformer steps down voltage by 2:1, the secondary load current limit is 700 mA RMS.
#1: Initial revision
by
Andy aka
·
2020-12-17T10:09:16Z (about 4 years ago)
> _If I connect this to a 12V supply and expose it to 10us pulse: 12V*10us/475uH = 252mA_
This is the current that flows in the primary magnetization inductance (475 μH) after applying 12 volts for 10 μs. This causes the core to saturate based on the volt-second figure limit of 11 volt-μs.
$$\dfrac{V\cdot dt}{L} = dI$$
The 350 mA AC figure will relate to the load current - this is unrelated to the magnetization current. Load current doesn't cause magnetization hence it can't create core saturation. This is because load current primary ampere-turns are cancelled entirely by load current secondary ampere-turns.