Topic Welding/Design1
Designing rectifier transformer for welding with 26Vdc, 200Adc
Input parameters
| Input | Voltage | 120V and 208V+-10%, 60Hz, sine wave |
| Wire | Al, round, single insulated, wound outside | |
| Output | Nominal DC output voltage | 26Vdc, via one phase rectifier bridge and smoothing choke |
| Nominal DC output current | 200Adc during 1.5 minutes and 8.5 minutes pause | |
| Wire | Al, rectangular wire, wound inside | |
| Core | Steel | M45, alternate stacking, not annealed |
| Bobbin | Type | Single section tube for EE 200/3” or EI long 150/75 |
| Design | Insulation class | H, max. nominal g temperature 165°C at ambient temperature 40°C, ventilated with 3 ft/s airflow |
| Criterion of design | Low price , high temperature rise |
General rules
1. The welding transformers are normally forced cooled with airflow 0ver 3 ft/s
2. The welding transformers work in duty cycle operation mode and the winding losses are much higher than core losses. Due to this fact you can use cheap steel quality and relative high induction.
3. The welding transformers with Al wires are bigger, cooler but cheaper.
4. The welding transformers are always protected by a thermal fuse
