Small distribution transformers from 25 to 1000 kVA are used to step down three-phase voltage of 6 or 10 kV to a lower 0.4 or 0.23 of frequency 50Hz for indoor and outdoor application.
Climatic region modification N1 under GOST 15150
Distribution transformers TM are equipped with conservator to permit the temperature depend expansion oil. Air entering the conservator is filtered and dehumidified. Oil level indicators are mounted directly on the conservator tanks to display the oil level
Radiators and corrugated provides an increase of cooling surface area
Tank-mounted transformer oil thermometers are normally installed for measurement of top oil temperature
Distribution transformers 1000 kVA are equipped with gas actuated relay
Distribution transformers from 400 to 1000 kVA are equipped with wheels allowing one to be rolled in
Conforms to GOST 11677-85 “Power Transformers. General Application”, GOST 27050-86 “Power transformers size I-III (capacities from 5 to 6300 kVA inclusive, voltage up to 35 kV)”
Technical data of ТМ-25..1000 kVA
| Rating [kVA] | Circuit version | Ur [kV] | Рsc [W] | Рo [W] | Uo [%] | Io [%] |
| 25 | У | 10 | 660 | 110 | 4,5 | 2,8 |
| 25 | D | 6 | 650 | 110 | 4,5 | 2,8 |
| 40 | У | 10 | 880 | 150 | 4,5 | 2,6 |
| 40 | D | 6 | 990 | 150 | 4,5 | 2,6 |
| 63 | У | 10 | 1280 | 220 | 4,5 | 2,4 |
| 63 | D | 6 | 1460 | 220 | 4,5 | 2,4 |
| 100 | У | 10 | 1970 | 305 | 4,5 | 2,2 |
| 100 | D | 6 | 2220 | 305 | 4,5 | 2,2 |
| 160 | У | 10 | 2650 | 460 | 4,5 | 2,0 |
| 160 | D | 6 | 3100 | 460 | 4,5 | 2,0 |
| 250 | У | 10 | 3700 | 560 | 4,5 | 1,9 |
| 250 | D | 6 | 4200 | 560 | 4,5 | 1,9 |
| 400 | У | 10 | 5500 | 830 | 4,5 | 1,5 |
| 400 | D | 6 | 6200 | 830 | 4,5 | 1,5 |
| 630 | У | 10 | 7600 | 1050 | 5,5 | 1,8 |
| 630 | D | 6 | 8500 | 1050 | 5,5 | 1,8 |
| 1000 | У | 10 | 10800 | 1550 | 5,5 | 1,2 |
| 1000 | D | 6 | 10800 | 1550 | 5,5 | 1,2 |