Dry-type power transformers
Description and Application
NTSM* transformers are of dry-type design, cast in cycloaliphatic resin, insulation class "F" (maximum permissible temperature 155°C). The transformation ratio of the transformer is given in the table. They are manufactured for a rated primary voltage of 25 kV, i.e. a highest voltage for equipment of up to 52 kV.
Among their wide range of applications, we particularly highlight their use on the railway at level crossings for powering signalling equipment.
Mounting and Maintenance
By design, these transformers are primarily used in locations that require resistance to flammability, moisture, chemical influences and short circuits. The transformers are designed for outdoor mounting and, due to their construction (creepage distances >31 mm/kV), can be installed in heavily polluted environments. The transformer is connected to the supply and outgoing conductors via stainless-steel terminals.
During the operation of dry-type epoxy transformers, almost no maintenance is required. It is recommended to periodically check that the connections on the transformer terminals are secure, since vibration can cause them to loosen. The transformer should also be wiped free of dust and other contamination.
Dry-type power transformers
NTSM-38-1.5 and NTSM-38-2.5
| Rated power (VA) | 1500 | Rated power (VA) | 2500 |
| Transformation ratio (kV/kV) | 25 / 0.22 | Maximum operating voltage (kV) | 27.5 |
| Highest voltage for equipment (kV) | 52 | Test voltage 50Hz, 1min (kV) | 95 |
| Impulse test voltage 1,2/50 (kV) | 250 | Lowest continuous operating voltage (kV) | 19 |
| Creepage distance (mm) / Insulation | 1329 mm | Cycloaliphatic resin | ||
| Weight (kg) | 85 kg | Weight (kg) | 102 kg |
| Secondary winding contacts (V) | Version 1 | Version 2 |
|---|---|---|
| A-N (Primary winding) | 25000 V | 25000 V |
| a1-n | 209 V | 220 V |
| a2-n | 220 V | 231 V |
| a3-n | 231 V | 242 V |
| a4-n | 242 V | 253 V |
| a5-n | 253 V | 264 V |
Dry-type power transformers
NTSM-38-5 and NTSM-38-10
| Rated power (VA) | 5000 | Rated power (VA) | 10000 |
| Transformation ratio (kV/kV) | 25 / 0.22 | Maximum operating voltage (kV) | 27.5 |
| Highest voltage for equipment (kV) | 52 | Test voltage 50Hz, 1min (kV) | 95 |
| Impulse test voltage 1,2/50 (kV) | 250 | Lowest continuous operating voltage (kV) | 19 |
| Creepage distance (mm) / Insulation | 1332 mm | Cycloaliphatic resin | ||
| Weight (kg) | 132 kg | Weight (kg) | 152 kg |
| Secondary winding contacts (V) | Version 1 | Version 2 |
|---|---|---|
| A-N (Primary winding) | 25000 V | 25000 V |
| a1-n | 209 V | 220 V |
| a2-n | 220 V | 231 V |
| a3-n | 231 V | 242 V |
| a4-n | 242 V | 253 V |
| a5-n | 253 V | 264 V |
Dry-type power transformers
NTSM-38-16, NTSM-38-20 and NTSM-38-25
| Rated power (VA) | 16000 | 20000 | 25000 |
|---|---|---|---|
| Transformation ratio (kV/kV) | 25 / 0.22 | 25 / 0.22 | 25 / 0.22 |
| Maximum operating voltage (kV) | 27.5 | 27.5 | 27.5 |
| Highest voltage for equipment (kV) | 52 | 52 | 52 |
| Test voltage 50Hz, 1min. (kV) | 95 | 95 | 95 |
| Impulse test voltage 1,2/50 (kV) | 250 | 250 | 250 |
| Lowest continuous operating voltage (kV) | 19 | 19 | 19 |
| Creepage distance (mm) | 1366 | 1366 | 1366 |
| Type of basic insulation | Cycloaliphatic resin | ||
| Weight (kg) | 328 kg | 350 kg | 370 kg |