What are the advantages/disadvantages of using copper vs. aluminum windings in a transformer?

Aluminium is less conductive, so there will be greater losses in the transformer. For the same power output, you would need a slightly larger transformer if you are using aluminium. On the other hand, aluminium is lighter and cheaper than copper. Overall, copper wins. - but everyone is flat out trying to design power transformers out of everything, which is why appliances are now so light, cheap, and likely to burst into flames.

 

Copper has better conductivity than aluminium, so its heat losses are lower. Making connections to a copper winding is easier than doing it to an aluminium winding. On turn aluminium is lighter than copper and its heat capacity is about three times the one of copper, thus allowing aluminiun to whistand better current overloads. From the point of view of corrosion aluminium may perform better but the wiring of a power transformer based on well enameled copper wire may last many years.

 

Aluminum = Less cost
Copper = better for everything else.

 

Indoor aluminum transformers weigh considerably less than indoor copper transformers, even after making them larger to accommodate the aluminum so that their efficiency matched or exceeded the competitor's copper transformer efficiency.

 

This is most important in high-rise office buildings that already have serious weight limits per floor (including service elevators) and especially per square foot (they can't handle high psi weight loads, much like airline floors with certain types of women's stiletto heels). I worked for a company for 13 years that manufactured very high powered UPS systems with very large aluminum foil wound transformers and we often won orders for the the upper floors of high-rise office towers simply because the competitor's copper transformers exceeded the weight per square foot allowance for the building and elevators. Keep in mind that these were the larger indoor transformers of 200kVA to 600kVA size. These are complex machines that occupy 3 feet x 6 feet x 6 feet areas or more. Some floors required up to 8 MWs of power.

 

Technical Parameter for 6kV, 10kV& 30kVA-2500kVA With Off Circuit Dry Type Transformer

(KVA)Rated capacity	Voltage Combination			Connection Group Symbol	No-load Loss(W)	Load Loss (W)			No-load Current (%)	Short-circuit Impedance(%)
	High Voltage (KV)	Tapping ranges of High Voltage	Low Voltage(KV)			130℃(B) (100℃)	155℃(F) (120℃)	180℃(H) (145℃)
30	6 6.3 6.6 10 10.5 11	±2.5% ±5%	0.4	Dyn11 Yyn0	190	670	710	760	2	4
50					270	940	1000	1070	2
80					370	1290	1380	1480	1.5
100					400	1480	1570	1690	1.5
125					470	1740	1850	1980	1.3
160					540	2000	2130	2280	1.3
200		±2X2.5% ±5%			620	2370	2530	2710	1.1
250					720	2590	2760	2960	1.1
315					880	3270	3470	3730	1
400					980	3750	3990	4280	1
500					1150	4590	4880	5230	1
630					1340	5530	5880	6290	0.85
630					1300	5610	5960	6400	0.85	6
800					1520	6550	6960	7460	0.85
1000					1770	7650	8130	8760	0.85
1250					2090	9100	9690	10300	0.85
1600					2450	11000	11700	12500	0.85
2000					3050	13600	14400	15500	0.7
2500					3600	16100	17100	18400	0.7
1600					2450	1220	12900	13900	0.85	8
2000					3050	15000	15900	17100	0.7
2500					3600	17700	18800	20200	0.7

 

Technical Parameter for 20kV 50kVA-2500kVA With Off Circuit Dry Type Transformer

(KVA)Rated capacity	Voltage Combination			Connection Group Symbol	No-load Loss(W)	Load Loss (W)			No-load Current (%)	Short-circuit Impedance(%)
	High Voltage (KV)	Tapping ranges of High Voltage	Low Voltage(KV)			130℃(B) (100℃)	155℃(F) (120℃)	180℃(H) (145℃)
50	20 22 24	±2.5% ±5%	0.4	Dyn11 Yyn0	340	1160	1230	1310	2	5.0
100					540	1870	1990	2130	1.8
160					670	2350	2470	3460	1.8
200		±2X2.5% ±5%			730	2770	2940	3140	1.8
250					840	3220	3420	3660	1.8
315					970	3850	4080	4360	1.8
400					1150	4650	4840	5180	1.1
500					1350	5460	5790	6190	1.1
630					1530	6450	6840	7320	1
800					1750	7790	8260	8840	1
1000					2070	9220	9780	10400	0.85
1250					2380	10800	11500	12300	0.85
1600					2790	13000	13800	14800	0.85
2000					3240	15400	16300	17500	0.7	8.0
2500					3870	18200	19300	20700	0.7
2000					3240	16800	17800	19100	0.7
2500					3870	20000	21200	22700	0.7

 

Technical Parameter for 35kV 50kVA-2500kVA With Off Circuit Dry Type Transformer

(KVA)Rated capacity	Voltage Combination			Connection Group Symbol	No-load Loss(W)	Load Loss (W)			No-load Current (%)	Short-circuit Impedance(%)
	High Voltage (KV)	Tapping ranges of High Voltage	Low Voltage(KV)			130℃(B) (100℃)	155℃(F) (120℃)	180℃(H) (145℃)
50	35 36 37 38.5	±2.5% ±5%	0.4	Dyn11 Yyn0	450	1340	1420	1520	2.3	6
100					630	1970	2090	2230	2
160					0.79	2650	2810	3000	1.5
200		±2X2.5% ±5%			0.88	3130	3320	3550	1.5
250					0.99	3580	3800	4060	1.3
315					1170	4250	4510	4820	1.3
400					1370	5100	5410	5790	1.1
500					1520	6270	6650	7110	1.1
630					1860	7250	7690	8230	1
800					2160	8600	9120	9760	1
1000					2430	9860	10400	11100	0.75
1250					2830	12000	12700	13600	0.75
1600					3240	14600	15400	16500	0.75
2000					3820	17200	18200	19500	0.75
2500					4450	20600	21800	23300	0.75

 

If you are interested in our products, please contact us or SEND INQUIRY to us, we will reply you within one hour.