Bank winding of HV SMPS transformer?

[N_Cook]

610 turns of 40AWG / 45 SWG wiring in 4 "layers" anyone experience of such
winding and thoughts on resulatant (lack of) structural integrity,
slip/sliding turns with temp cycling/magnostriction etc leading to failure.
I've never seen a transformer design brief, so perhaps interesting to others
on that aspect alone
Tektronix 7834 scop HV transformer,(flyback misnomer)
http://www.ko4bb.com/Manuals/Tektronix/Tektronix_-_7834/Tek7834_Flyback_Tran
sformer_Winding%20_Spec.pdf

some general info including bank winding, I've only ever seen on high DC
chokes so structurally sound
http://focus.ti.com/lit/ml/slup125/slup125.pdf

 

[nesesu]

On Dec 11, 7:06 am, "N_Cook" <dive...@tcp.co.uk> wrote:

610 turns of 40AWG / 45 SWG wiring in 4 "layers" anyone experience of such
winding and thoughts on resulatant (lack of) structural integrity,
slip/sliding turns with temp cycling/magnostriction etc leading to failure.
I've never seen a transformer design brief, so perhaps interesting to others
on that aspect alone
Tektronix 7834 scop HV transformer,(flyback misnomer)http://www.ko4bb.com/Manuals/Tektronix/Tektronix_-_7834/Tek7834_Flyba...
sformer_Winding%20_Spec.pdf

some general info including bank winding, I've only ever seen on high DC
chokes so structurally soundhttp://focus.ti.com/lit/ml/slup125/slup125.pdf

Not sure what you are getting at. According to the winding winding
diagram and notes, the 610 turn winding is machine wound in a 'bank'
winder so it should be tight and even. I would expect that the #40AWG
wire is 'served' with polyester yarn which gives it a high surface
friction so the turns tend to lock together. Finially, I imagine the
finished coil assembly is vacuum 'varnished' to seal out moisture and
fill all air gaps as well as lock the whole assembly into a solid
mass.
I am surprised to see bank winding is back in fashion; we used to bank
wind torroids 50 years ago to give minimal parallel capacitance to the
inductance, but that seemed to fade out when ferrite pot cores
replaced powdered iron torroid cores through the '60s. For very low
capacitance coils we would then use 'Pi' or 'universal' wound coils,
but they too must be flooded with a sealing compound to lock their
rather frail structure that relies wholly on wire tension for
stability in the 'as wound' state.

Neil S.

 

[N_Cook]

nesesu <neil_sutcliffe@telus.net> wrote in message
news:1220b16b-7a98-448c-81a3-48ab260b9f47@p7g2000prb.googlegroups.com...
On Dec 11, 7:06 am, "N_Cook" <dive...@tcp.co.uk> wrote:

610 turns of 40AWG / 45 SWG wiring in 4 "layers" anyone experience of such
winding and thoughts on resulatant (lack of) structural integrity,
slip/sliding turns with temp cycling/magnostriction etc leading to
failure.
I've never seen a transformer design brief, so perhaps interesting to
others
on that aspect alone
Tektronix 7834 scop HV transformer,(flyback
misnomer)http://www.ko4bb.com/Manuals/Tektronix/Tektronix_-_7834/Tek7834_Fly

ba...

sformer_Winding%20_Spec.pdf

some general info including bank winding, I've only ever seen on high DC
chokes so structurally soundhttp://focus.ti.com/lit/ml/slup125/slup125.pdf

Not sure what you are getting at. According to the winding winding
diagram and notes, the 610 turn winding is machine wound in a 'bank'
winder so it should be tight and even. I would expect that the #40AWG
wire is 'served' with polyester yarn which gives it a high surface
friction so the turns tend to lock together. Finially, I imagine the
finished coil assembly is vacuum 'varnished' to seal out moisture and
fill all air gaps as well as lock the whole assembly into a solid
mass.
I am surprised to see bank winding is back in fashion; we used to bank
wind torroids 50 years ago to give minimal parallel capacitance to the
inductance, but that seemed to fade out when ferrite pot cores
replaced powdered iron torroid cores through the '60s. For very low
capacitance coils we would then use 'Pi' or 'universal' wound coils,
but they too must be flooded with a sealing compound to lock their
rather frail structure that relies wholly on wire tension for
stability in the 'as wound' state.

Neil S.

&&&&&&

I was trying to visualise the mechanics of the winding machine, backlash
error for the reversing cam , once per bank,150 times for this coil. Runout
error trying to keep the overall traverse in step with the banking over the
width of run. And all the time just surface tension , assumed wound wet, to
stop the turns avalanching down the bank slopes.