iron core saturation

Status
Not open for further replies.

MacIntoshCZ

Active Member
Hello there,
where do you think the core is saturated? Thanks

Its hard to determine where i should place cursors.
 
Last edited:
VCC is 11,2V, current sense resistor is 1,5R., core area is aprox 70mm2, turns = 10
If you consider those values i got as results:
L = VCC*time/(Ursense/Rsense) = 11,2*2,6*10E-6/(2,83/1,5) = 15,5uH
Bs = L*(Ursense/Rsense)/(Turns*Area) = 15,57*10E-6*(2,83/1,5)/(10*70*10E-6) = 42mT

42mT is really low value.
 
Last edited:
There is no saturation in that screenshot. If there were, the rate of rise of current would start increasing instead of decreasing. This looks like a normal response of RL circuit, where the current increases exponentially up to Vcc/(Rsense +Rinductor)
 
Its not as clear as measuring on ferrite coil. My R4 is gonna smell horribly if i increase it a little bit
 
The B/H graph is a completely different thing to what you are measuring. If there was saturation the graph would look like this

The pulse is quite short, you can let it run for say 100us and the resistor will be fine, just repeat the pulse only every second or so. You will see the graph tapers off at 11.2V.
 
Green is core with no saturation, blue is with saturation. You can see how the current starts rapidly increasing at one point.
 

Attachments

  • saturation.asc
    668 bytes · Views: 290
thanks for info, I changed R4 from 1R5 to 0.1R. Still looks linear.
Now its different story.
Now 1Tesla without saturation
 
I need better device. Just few pulses. This takes like 20W. Looks like task for MCU.
Or even better - just lower frequency to something like 100Hz
 
Last edited:
How about an 555 oscillator at 1Hz triggering a monostable 555 one-shot with small duration like 100us, then a gate driver, for example IR2113.
 
kubeek said:
How about an 555 oscillator at 1Hz triggering a monostable 555 one-shot with small duration like 100us, then a gate driver, for example IR2113.
Click to expand...
I am actually using ir2153. I chose 6,8M Resistor for R_off (biggest i found) CT is 10nF, Now i have 15Hz aprox.
 
I am starting to hate emf / emi what else....
I am again suffering with non-saturating coil.
When i connect it to two different powersupplies, 15Hz frequency works but it looks strange.
When i connect it only (that means power part and control part have same vcc) to second PSU (laptop charger) it starts to oscillate on 2khz frequency. i though it has not enough power, I added 15mF (yes mili) cap to VCC. No differents
Those experiments makes me love electronics...
 

Attachments

  • coil current.png
    81.9 KB · Views: 274
  • coil.png
    76.2 KB · Views: 290
  • DS_mosfet.png
    75.7 KB · Views: 278
  • gate.png
    73.2 KB · Views: 282
Last edited:
Worth mention that current is 82A!!! Its measured on 10miliohm resistor. And it with 10x times probe.
In this case Bsmax is 1,5Tesla. Maybe mosfet do not like high current pulses? =) Also 82A could cause some voltage drops.
I am using if3205
 
Status
Not open for further replies.

Similar threads

C
  • Question
Soldering iron issues
2
Replies
21
Views
3K
shokjok
S
  • Question
Toroidal ferrite core size
Replies
1
Views
1K
augustinetez
A
F
  • Question
Kapton gapped PQ26/20 ferrite core
Replies
2
Views
1K
ChrisP58
A ferrite core & 6' of 24AWG enameled wire
Replies
7
Views
2K
ThomsCircuit
C
  • Question
Advice on Weller soldering iron tips etc.
2
Replies
26
Views
9K
Philip76
P
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…