No, the integral solder ring fitting has the correct amount of solder to form a joint.
Copper will not harden during storage; it does not have a shelf life.
Much less water.
No, brass retains its toughness at low temperatures.
No. Studies show that as uncoated copper, brass and bronze surfaces oxidise, or darken, they retain their hygienic qualities.
After machining clean the components with hot detergent, rinse thoroughly in cold water then immerse in a tarnish inhibitor (a mixture of monoethylene glycol and benzotriazole) then dry in air.
At room temperature, Cu-ETP should be used. However, it begins to soften at 150oC, so at higher temperatures the following may be used with only a slight loss of conductivity:
- CuAg0.10 up to 250oC to 300oC
- CuZr,CuCr1zr,CuNi2Si to 350—400oC
Either by the use of lacquers, wax polishing, or both.
The key is to clean them thoroughly, remove water, protect them and keep them dry, so:
- After cleaning dry thoroughly using a dewatering fluid such as WD40.
- Remove displaced water with forced warm air.
- Coat with a protective coating such as benzotriazole inhibitor, or a block co-polymer.
- Pack into benzotriazole treated paper lined wooden boxes. Moisture absorbent granules may also be used to keep the air inside the boxes dry.
When unpacked, remove the coatings with a phosphoric-based solution and dry them thoroughly.
It depends on the type of load on the transformer.
Transformer losses are of two types; those that are independent of the load (known as ‘no-load’ losses) and those that vary with load (known as ‘load losses’ or, sometimes, as ‘copper losses’). ‘No-load losses’ are present all the time that the transformer is energised, whether loaded or not. Most of the no-load losses occur in the magnetic steel of the core. ‘Load losses’ are proportional to the square of the load current and so are greatest when the transformer is highly loaded. Transformers are manufactured to meet standard types defined by standards or to meet specific customer requirements.
As a rule of thumb, if the loading is high, such as in an industrial plant, purchase of a transformer with reduced load losses will be beneficial. If the transformer is lightly loaded, such as a hot standby transformer, a transformer with reduced no-load losses will be beneficial. In other cases, it is necessary to calculate the benefit. The SEEDT report gives more information on transformer losses. (2008, 32pp).
Copper sheets are fixed with clips, some fixed and some sliding, which allow the copper to expand and contract with changes in the temperature. If the copper is fixed rigidly then splits in the sheet may occur.
For long circuits, or high power or high duty cycle circuits, energy losses in cable should be considered. Wiring standards normally recommend that the voltage drop in installation wiring is kept to below 2.5%. That represents a power loss of 2.5%, so the cable, as installed, is only 97.5% efficient. Increasing the conductor cross-section reduces voltage drop and energy loss, but increases the cost of the cable. The process of finding the optimum conductor size – for which the lifetime cost is lowest – is described in Pub 116 – Electrical Energy Efficiency. Our cable sizing software allows the optimum size to be calculated easily.