Planned on that. In fact the PT will be at one end and the OPT's at the other similar to Audiotropics Machine. It just seems like there would be less problems by bringing in the B+ on one side of the transformer, while the output would be on the other near side near the edge of the chassis. I'm going to have to cross the secondaries at some point with the B+ I think.
Haven't got to your e-mail yet. I have been either chained to my computer at work, or traveling 500 miles 6 out of the last 8 weekends to move my mother into assisted living. I got about 200 e-mails to answer.
I have had no issues wiring up the Edcors with out paying much attention to routing the wires. I have even connected them up with clip leads (don't do this at home). The signal levels are very high at this point, so noise pickup is not an issue. Just make sure any low level wiring (like the input connections) does not come near the transformers, and as stated before, make sure the power transformer is rotated 90 degrees from the OPT's. I just wish that Edcor would have put the primary leads (high voltage) on the bottom. It would make them harder to accidentally touch. Put heat shrink on the leads.
I have had no issues wiring up the Edcors with out paying much attention to routing the wires. I have even connected them up with clip leads (don't do this at home). The signal levels are very high at this point, so noise pickup is not an issue. Just make sure any low level wiring (like the input connections) does not come near the transformers, and as stated before, make sure the power transformer is rotated 90 degrees from the OPT's. I just wish that Edcor would have put the primary leads (high voltage) on the bottom. It would make them harder to accidentally touch. Put heat shrink on the leads.
sorenj07 said:
Don't worry, solids have the highest heat conductivity.
http://www.clavius.org/heatxfer.html
Wow. That's kind of weird because on Angela's website, they have the following statement:
Please note, potting these transformers is not recommended and will void the warranty. Mark Mercer of Hammond writes ..."due to the design, our transformers will not last very long if they are potted. The design calls for air-cooling. By potting you trap the core and build up too much heat."
Admittedly it's about hammond's line of 2xx-series power transformers but still. Maybe an email to the Edcor could settle this?
Please note, potting these transformers is not recommended and will void the warranty. Mark Mercer of Hammond writes ..."due to the design, our transformers will not last very long if they are potted. The design calls for air-cooling. By potting you trap the core and build up too much heat."
Admittedly it's about hammond's line of 2xx-series power transformers but still. Maybe an email to the Edcor could settle this?
the point is, the heat HAS to get dissipated to the air at some point; are the potting material and the metal can itself just more impediments for that heat to radiate/convect out? i think so, unfortunately.. it just depends on how much of an issue it is.
edit: unless, of course, the pots you use are machined aluminum with heat-radiating fins on the outside, like the cylinders on a motorcycle
edit: unless, of course, the pots you use are machined aluminum with heat-radiating fins on the outside, like the cylinders on a motorcycle
I don't see any impediments. Metal can and potting compounds have better heat conductivity than air.
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html
http://www.trafomo.dk/master/products_info.asp?produktID=55
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html
http://www.trafomo.dk/master/products_info.asp?produktID=55
I agree that potting a transformer that wasn't designed to be potter can have thermal consequences. Especially a big power transformer.
In this case we are talking about a small OPT with a 130 ohm primary, that is rated at 80ma. The DC losses add up to 832 milliwatts, and with some ineficiencies at audio, the transformer might dissipate 1 watt. Heat isn't an issue here. Whatever you pot the transformer with may not be compatible with the materials that were used to make it, and an early failure might occur. Just make a pretty box (or can) to put them in. No potting is needed. 1 watt isn't going to bake it.
In this case we are talking about a small OPT with a 130 ohm primary, that is rated at 80ma. The DC losses add up to 832 milliwatts, and with some ineficiencies at audio, the transformer might dissipate 1 watt. Heat isn't an issue here. Whatever you pot the transformer with may not be compatible with the materials that were used to make it, and an early failure might occur. Just make a pretty box (or can) to put them in. No potting is needed. 1 watt isn't going to bake it.
Potted transformers are highly protected from environmental dangers. They provide:
Moisture Resistance: The potting compound guards the transformer in damp and humid environments, including wave soldering processes and wash rinses.
Mechanical Strength: The potting compound protects the wire and complete winding from accidental cutting, dirt entrapment, and other hazards, so potted transformers are perfectly suited for industrial environments
Shock and Vibration Resistance: The potting compound strengthens the grip of the pins, so the transformer requires no additional clamping on the PC board. All bobbins have up to 20 pin placement options. When applications require extreme shock and vibration resistance, we can add pins to further improve PC board adhesion.
Increased Heat Transfer: The potting compound conducts heat more efficiently than air in an open-frame transformer, which results in a higher power/volume ratio
In addition to these mechanical advantages, potted transformers offer an important electrical advantage over open frame transformers.
Enhanced Insulation System: Our potting process is performed under vacuum, eliminating any air gaps or pockets in the potting compound. Accordingly, testing agencies consider the potting compound an insulator. This reduces spacing requirements, resulting in smaller packages with better insulation.
Source: http://www.advancedcomponents.com/store/
Could you describe the differences between transformer designed to be potted and the other one?
Moisture Resistance: The potting compound guards the transformer in damp and humid environments, including wave soldering processes and wash rinses.
Mechanical Strength: The potting compound protects the wire and complete winding from accidental cutting, dirt entrapment, and other hazards, so potted transformers are perfectly suited for industrial environments
Shock and Vibration Resistance: The potting compound strengthens the grip of the pins, so the transformer requires no additional clamping on the PC board. All bobbins have up to 20 pin placement options. When applications require extreme shock and vibration resistance, we can add pins to further improve PC board adhesion.
Increased Heat Transfer: The potting compound conducts heat more efficiently than air in an open-frame transformer, which results in a higher power/volume ratio
In addition to these mechanical advantages, potted transformers offer an important electrical advantage over open frame transformers.
Enhanced Insulation System: Our potting process is performed under vacuum, eliminating any air gaps or pockets in the potting compound. Accordingly, testing agencies consider the potting compound an insulator. This reduces spacing requirements, resulting in smaller packages with better insulation.
Source: http://www.advancedcomponents.com/store/
tubelab.com said:
Could you describe the differences between transformer designed to be potted and the other one?
Zibi said:
Potting compounds can have better heat conductivity than air but not all do. Not all solids conduct heat better than air. Regular epoxy for instance does not .
If you can get potting compound specifically made to be more heat conductive than epoxy then go for it. If you plan on using regular epoxy then good luck. There is a real reason that Hammond does not recommend potting their unpotted trafos.
Air properties: http://www.engineeringtoolbox.com/air-properties-d_156.html
other materials: http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thrcn.html#c1
Have you any regular epoxy data?
other materials: http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thrcn.html#c1
Have you any regular epoxy data?
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