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Old 4th April 2005, 03:47 PM   #11
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Quote:
Originally posted by jacco vermeulen
The 2" hole suggests more a 300VA.
I was wondering about the 2" hole being heavier duty (higher va). The cut sheets I've seen don't state hole size.
Quote:
Originally posted by jacco vermeulen
Up till 300va 1kg/100va is fairly accurate(+50grams for the smaller of size).
Between 425va and 800va the factor is 0.8 kg/100va.
From 1000va it drops to 0.75 kg/100va and lower.
Good info.
Quote:
Originally posted by jacco vermeulen
But i am very curious if it is a 5.0 or a 6.5 pounder.
I won't be able to get it weighed until the end of week.
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Old 4th April 2005, 03:50 PM   #12
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How would I go about testing for the maximum va? I have load resistors and thermister temperature probe.
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Old 10th April 2005, 02:18 PM   #13
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I've been holding off weighing my toroid transformer because I was expecting delivery of another toroid this weekend. It arrived, I'll be weighing them this week.

In the mean time of have a wiring question. The newer toroid has dual primary coils and two sets of center tap secondaries. See pic for info and note lead gauges.

Is it better to wire primaries in series or parallel?

It appears better for me to wire 120 volt primaries in series, the blue lead are 18 gauge and suggests it could handle more current.

Is there a problem with this?

What fuse sizes would you suggest?

Thanks Phil
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Old 10th April 2005, 02:55 PM   #14
BWRX is offline BWRX  United States
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if you're looking for lower voltage on the secondaries then wire the primaries in parallel. it sounds like a pretty big transformer so you'll need a decent size fuse. what is the VA rating of this new one?
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Old 10th April 2005, 04:16 PM   #15
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Meaning:
the output voltage of a transformer is determined by the ratio of primary and secondary winding.

Put two 120v windings in series;
>> twice the number of windings
>> twice the ratio
>> output voltage on the secondary is half of that when two primaries are in parallel.

Put the 2 120v primaries in series and place 240v on the primary.
>> twice the voltage>> primary resistance is twice>> same current>> 240*A = 120*A + 120*A.
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Old 10th April 2005, 07:56 PM   #16
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Hi jacco vermeulen,

This toroid is more usable to be wiring primary coils in series (see pic). 24-0-24 volt secondary for gainclone and 8-0-8 volt secondary for preamp.

How will wiring primary coils in series effect va output?
Will va go up or down with primary in series?
What would fuse sizes be this way?
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Old 10th April 2005, 08:11 PM   #17
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Quote:
Originally posted by mrlots2do
How will wiring primary coils in series effect va output?
running thr trafo wired for 240V on 120V will effectively halve the VA, but the trafo will have very low stress.

dave
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Old 10th April 2005, 08:35 PM   #18
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General transformer estimating question: While you can't see the gauge of the windings, couldn't you use the gauge of the primary and secondary leads as a guide to determining the current limit? Or do their short length make this more difficult?

Not sure how much impact it has on weight, but Plitrons have the core filled with epoxy so they will weigh somewhat more.
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Old 10th April 2005, 09:32 PM   #19
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Quote:
Originally posted by ultrachrome
Not sure how much impact it has on weight, but Plitrons have the core filled with epoxy so they will weigh somewhat more.
None of mine do...

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Old 10th April 2005, 10:44 PM   #20
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Quote:
Originally posted by planet10


None of mine do...

dave
They may weight a little more but nothing to notice. All mine are epoxy filled too.
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