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stefuel
Joined: 07 Mar 2006 Posts: 3353 Location: Green Harbor MA USA
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Link Posted: Tue Mar 24, 2009 10:08 am Post subject: Thermal fuses on transformers "to protect the transform |
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If the idea is truly to protect the transformer, then why the heck do they bury them deep inside the windings so that it is un-serviceable. It's junk anyway.
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Heywood Jablome
Joined: 12 Mar 2006 Posts: 1547
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Link Posted: Tue Mar 24, 2009 11:55 am Post subject: |
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Because the transformer would already have melted down and shorted by the time a more serviceable fuse pops... (being thermal, at least in part, it must be embedded in the windings.) I'm surprised it's not a Klixon self-resetting circuit breaker.
_________________ "Those countries which lag behind in industry, in the application of mechanics and technical chemistry, in the careful selection and utilization of natural products, where the respect for such activities does not permeate all classes of society, will unfailingly decline in prosperity. They will sink faster when neighbor states, with an energetic exchange between science and industry, go forward with renewed vitality."
-- Baron Alexander von Humboldt: 1769-1859
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perisoft
Joined: 29 Aug 2007 Posts: 2920 Location: Ithaca, NY
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Link Posted: Tue Mar 24, 2009 2:30 pm Post subject: |
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Are we talking autobot or decepticon here? It makes a difference, you know...
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24305 Location: Langley, BC
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Link Posted: Tue Mar 24, 2009 2:32 pm Post subject: |
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It's almost always an easy fix. Cut open the outside wax paper layer of the windings, expose the fuse solder points, short out the fuse with a jumper wire, throw electrical tape around the whole transformer to hide the exposed 110 volt windings, you're done.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Tue Mar 24, 2009 3:21 pm Post subject: |
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perisoft wrote: | Are we talking autobot or decepticon here? It makes a difference, you know... |
Damn you beat me to it Optomus.
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Tinman
Joined: 09 Mar 2006 Posts: 1326 Location: Carson City Nevada
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Link Posted: Tue Mar 24, 2009 11:27 pm Post subject: |
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Curt Palme wrote: | It's almost always an easy fix. Cut open the outside wax paper layer of the windings, expose the fuse solder points, short out the fuse with a jumper wire, throw electrical tape around the whole transformer to hide the exposed 110 volt windings, you're done. |
Do you offer fire insurance with that, Curt?
I've certainly done that, but I replace the damn fuse! Don't give anyone ideas.
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stefuel
Joined: 07 Mar 2006 Posts: 3353 Location: Green Harbor MA USA
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Link Posted: Tue Mar 24, 2009 11:49 pm Post subject: |
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wooopsie double stamped
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stefuel
Joined: 07 Mar 2006 Posts: 3353 Location: Green Harbor MA USA
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Link Posted: Tue Mar 24, 2009 11:49 pm Post subject: |
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I'd be happy as a pig in $hit just to get it going long enough to figure out the secondary voltage. That way I could source a aftermarket transformer to replace it with.
_________________ Chip
A Barco is only a AmPro with training wheels
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stefuel
Joined: 07 Mar 2006 Posts: 3353 Location: Green Harbor MA USA
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Link Posted: Wed Mar 25, 2009 12:16 am Post subject: |
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Heywood Jablome wrote: | Because the transformer would already have melted down and shorted by the time a more serviceable fuse pops... (being thermal, at least in part, it must be embedded in the windings.) I'm surprised it's not a Klixon self-resetting circuit breaker. |
A fuseable link is way cheaper and takes up way less space and makes it throw-away. Just the way the suppliers like it
_________________ Chip
A Barco is only a AmPro with training wheels
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24305 Location: Langley, BC
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Link Posted: Wed Mar 25, 2009 12:42 am Post subject: |
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Tinman wrote: |
Do you offer fire insurance with that, Curt?
I've certainly done that, but I replace the damn fuse! Don't give anyone ideas. |
Frankly, I don't bother. I've NEVER had a thermal fuse blow for good reason, ie transformer shorted, causing overheating.
EVERY amp, receiver. etc that I've seen has had another fuse to protect the unit in case of overload, (in series with the line cord) so there's already protection.
I don't think anything electronic with only a thermal fuse internal to the transformer would pass US or Canadian electrical code.
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lostmandan
Joined: 09 Jul 2008 Posts: 146 Location: Kitchener/Waterloo, Ontario, Canada
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Link Posted: Wed Mar 25, 2009 2:09 am Post subject: |
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I had to replace a control board on a kitchen stove because of a thermal fuse issue. The power was out and when it came back on the stove controller transformer got nuked. I ended up buying the minimum quantity of 25 fuses to replace the defective on the transformer. I guess I could have jumped it but I figure a stove is plugged in 24/7 and not exactly a safe device if something untoward happens.
I had been told that jumping the fuse on the control would cause problems with insurance if anything happened. That being said, it was the manufacturer's repair center that told me. I politely declined to buy the $450 control and dug up the fuses online.
That being said, I have run an older Sansui receiver for over a decade with a jumper over the thermal fuse. Another example of a weak fuse - no over heat, no excessive load - the device just went open and made the receiver garbage.
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stefuel
Joined: 07 Mar 2006 Posts: 3353 Location: Green Harbor MA USA
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Link Posted: Wed Mar 25, 2009 2:58 am Post subject: |
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Curt Palme wrote: | Tinman wrote: |
Do you offer fire insurance with that, Curt?
I've certainly done that, but I replace the damn fuse! Don't give anyone ideas. |
Frankly, I don't bother. I've NEVER had a thermal fuse blow for good reason, ie transformer shorted, causing overheating.
EVERY amp, receiver. etc that I've seen has had another fuse to protect the unit in case of overload, (in series with the line cord) so there's already protection.
I don't think anything electronic with only a thermal fuse internal to the transformer would pass US or Canadian electrical code. |
This is a transformer in a power supply that is part of the amp in a active subwoofer. It does have a fuse on the line in and a thermal on/in the transformer. The owners manual states that if the thermal blows, you must replace the transformer. My gripe is, there are many things external to the transformer that can cause it to heat up, not just shorted windings.
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24305 Location: Langley, BC
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Link Posted: Wed Mar 25, 2009 1:16 pm Post subject: |
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As I said, I've never had a case where one of those fuses blew for a legit reason. To boot, I used to work at a small appliance/TV repair shop, and countless thermal fuses were replaced in coffee makers. I think I remember hearing the appliance guy say once:
'Wow, a thermal fuse actually blew because the heating element was shorted'. Every other time, the fuse blew for no reason. In a coffeemaker however, that fuse is the ONLY fuse in the unit, and yes, in that case it was never bypassed.
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stefuel
Joined: 07 Mar 2006 Posts: 3353 Location: Green Harbor MA USA
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Link Posted: Wed Mar 25, 2009 10:03 pm Post subject: |
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Well you might be right. I don't have it in front of me at this time. The power input fuse has been checked and is OK. It seems as it is not getting power. When it gets here I'll ge to the bottom of it.
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Tinman
Joined: 09 Mar 2006 Posts: 1326 Location: Carson City Nevada
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Link Posted: Thu Mar 26, 2009 1:02 am Post subject: |
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Yeah Curt, I agree with ya there. I have yet top see a blown thermal fuse due to heat. I think they pop from surge current most of the time. Regardless, I always fuse the transformer again, even if it's only a regular fuse. Just in case.
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