Prev: VCC width
Next: Can anyone suggest a single chip 2400 baud modem solution please?
From: Jasen Betts on 18 May 2010 04:41
On 2010-05-17, slither <zxc981(a)n_o_s_p_a_m.hotmail.com> wrote:
> Hi everyone,
>
> I'm currently trying to design a 20kVA (11kV - 230V) pole mount
> distribution transformer for a project. I'm having some difficulties
> deciding which core material and winding materials to use for the design.
>
> How do i know what type of cold rolled grain oriented steel to use in the
> core and what thickness the laminations should be?
>
> How do i know what the thickness and type (Aluminium,copper, round or
> square) of my winding materials (primary and secondary) should be? Finally,
> how much insulation should be placed between the winding layers?

Sure sounds like a homework question.

> Overall, i'm not really sure how to match my transformers application with
> suitable materials.

pick some figures and run the math see how much you loose in resistive
losses, eddy currents, and the like.

adjust the figures, repeat.


--- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: whit3rd on 19 May 2010 14:21
On May 17, 5:07 am, "slither" <zxc981(a)n_o_s_p_a_m.hotmail.com> wrote:

> I'm currently trying to design a 20kVA (11kV - 230V) pole mount
> distribution transformer for a project. I'm having some difficulties
> deciding which core material and winding materials to use for the design.
>
> How do i know what type of cold rolled grain oriented steel to use in the
> core and what thickness the laminations should be?
>
> How do i know what the thickness and type (Aluminium,copper, round or
> square) of my winding materials (primary and secondary) should be? Finally,
> how much insulation should be placed between the winding layers?

This is going to take some research into the economics. Your best
core design depends on the relative cost of lost energy and the
best specialty materials. You'll make a cost-amortization
calculation.

The design of pole pig transformers includes cooling oil and
enclosures, mechanical mount provisions, bird-tolerance, weather
resistance, transient overvoltage and overload tolerance, etc.

Looking up steel formulations for the magnetic properties will only
give
you an idealized (fully-annealed unstressed) sample's properties, NOT
the full as-manufactured performance of the finished product.

The stuff between windings is only PARTLY insulation; it's also
mechanical
stress relief.

Really designing one of these for mass-production is a daunting task.
Have fun!
From: Cydrome Leader on 17 Jun 2010 15:30
whit3rd <whit3rd(a)gmail.com> wrote:
> On May 17, 5:07?am, "slither" <zxc981(a)n_o_s_p_a_m.hotmail.com> wrote:
>
>> I'm currently trying to design a 20kVA (11kV - 230V) pole mount
>> distribution transformer for a project. I'm having some difficulties
>> deciding which core material and winding materials to use for the design.
>>
>> How do i know what type of cold rolled grain oriented steel to use in the
>> core and what thickness the laminations should be?
>>
>> How do i know what the thickness and type (Aluminium,copper, round or
>> square) of my winding materials (primary and secondary) should be? Finally,
>> how much insulation should be placed between the winding layers?

If you check a catalog or actually open such a transformer up you'll find

aluminum primary, aluminum secondary would from flat straps, a step-lap
core and insulation made of transformer paper, probably epoxy cured and
then the tank filled with oil for cooling and insulation.

some places might still use copper, but it costs more so utilities don't
care for that.

distribution transformers are designed to be efficient and to not rip into
pieces if they experience a fault. the magnemotive forces can be quite
high in such large devices.


First  |  Prev  | 
Pages: 1 2
Prev: VCC width
Next: Can anyone suggest a single chip 2400 baud modem solution please?