To optimize the electrical conductivity of copper die-cast rotors, it is necessary to use a copper alloy having very low levels of impurities. As shown in Figure 2.1.1, even low levels of most impurity elements will significantly increase the electrical resistivity of copper.
Figure 2.1.1. Influence of dissolved impurity elements on the electrical conductivity of copper at ambient temperature(Copyright 1980 Olin Corporation. Used with Permission. All rights reserved )
Therefore, it is recommended that alloys C10100 or C11000 be used for die-casting copper rotors. As shown in Table 2.1.1, both these alloys have electrical conductivities of 101% IACS.
| Alloy | Common Name | Electrical Conductivity |
|---|---|---|
| C10100 | Oxygen free electronic copper | 101% IACS |
| C11000 | Electrolytic tough pitch copper | 101% IACS |
The chemical compositions of alloy C10100 is shown in Table 2.1.2, and alloy C11000 in Table 2.1.3. Additional information about these two alloys can be found in ASTM B 224, "Standard Classification of Coppers".
| Element | Nominal | Minimum | Maximum |
|---|---|---|---|
| Copper | -- | 99.99 | -- |
| Residual deoxidants | -- | None | |
| Phosphorus | -- | -- | 0.0003 |
| Tellurium | -- | -- | 0.0010 |
| Other named elements* | -- | -- | -- |
| *Hg, max., 1 ppm (0.0001%); Zn, max., 1 ppm, (0.0001%); Cd, max., 1 ppm, (0.0001%); S, max., 18 ppm (0.0018%); Pb, max., 10 ppm (0.0010%); Se, max., 10 ppm (0.0010%); Bi, max., 10 ppm (0.0010%); Oxygen max., 10 ppm (0.0010%) The total of the seven following elements, Se, Te, Bi, As, Sb, Sn and Mn not to exceed 40 ppm, (0.0040%). |
|||
| Element | Nominal | Minimum | Maximum |
|---|---|---|---|
| Copper (inc. silver) | -- | 99.90 | -- |
| Oxygen | 0.04 | -- | -- |