in spot welding machine every mains cycle is controlled,
in some low power welding the transformer is on only for one or two
mains cycle, the phase angle is controlled for every half cycle according
to the output current requirement.
Share your stuff or I will make you regret it.
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1
on: April 29, 2025, 05:30:05 05:30
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| Started by max - Last post by max | ||
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2
on: April 28, 2025, 09:25:40 09:25
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| Started by max - Last post by cicos | ||
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There are devices that work by switching on the primary transformers available on aliexpress, but they have their drawbacks (I have one of those) and now I will try the modification that I found on YT.
Pozzz, JaMi |
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3
on: April 27, 2025, 07:01:03 19:01
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| Started by max - Last post by bobcat1 | ||
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If your device sits on the primary side. What I think your device is, is a transformer softstart device to avoid high current at startup. A telltale would be if you have a relay in parallel with the triac. This relay will short out the triac at the point steady for the transformer is achieved This might work if the timing will no longer then 300msec - use a micro to control the relay and the TRIAC All the best Bobi |
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4
on: April 27, 2025, 06:26:41 06:26
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| Started by max - Last post by Sideshow Bob | ||
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If your device sits on the primary side. What I think your device is, is a transformer softstart device to avoid high current at startup. A telltale would be if you have a relay in parallel with the triac. This relay will short out the triac at the point steady for the transformer is achieved
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5
on: April 26, 2025, 07:43:49 19:43
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| Started by max - Last post by bobcat1 | ||
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Hi
Driving a transformer with a Triac (not SCR) is problematic - due to lenz law creating a huge current spike while switching a high inductance coil All the best Bobi |
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6
on: April 26, 2025, 07:37:06 07:37
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| Started by max - Last post by max | ||
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I have an analog controller which is working ok with 200kva transformer,
I am tracing the sch when it is ready i will post it, I hope someone can simulate it in proteous to get the waveform. Regards |
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7
on: April 25, 2025, 01:35:41 01:35
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| Started by jykim - Last post by jykim | ||||||
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8
on: April 23, 2025, 08:30:35 08:30
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| Started by max - Last post by Sideshow Bob | ||
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You do have ICs that implement that
https://www.google.com/search?q=zero+crossing+triac+driver However driving a transformer this way may perhaps not be doable. Because due to many reasons. We had a lengthy discussion about how to handling powering on large transformer 50/60 Hz transformers a few years back. Even loosing a few cycles may demagnetize the core |
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9
on: April 22, 2025, 12:16:20 12:16
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| Started by balkytheking - Last post by balkytheking | ||||||
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10
on: April 20, 2025, 05:41:06 05:41
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| Started by max - Last post by max | ||
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Hi,
I need to control a spot welding 200kva single phase transformer using scr phase control, please advise methods and what precautions are necessary for zero crossing sensing and scr gate triggering. the voltage is 400vac using two phases. Regards |
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