Stator Diamond Coils
Electrical Routine Test
The electrical routine testing at different stages is performed with guidelines of IEEE/IEC/IS international standards. The High voltage test on individual coils and Stator winding is shall perform as per our below standard norms or customer specific requirement
| S.no | Stage of testing | Electrical Test | Resin Rich coils | VPI coils | Hybrid Insulation |
1 | Test on Individual coils | Tan delta and capacitance measurement with guard electrodes | The tan delta measurement carried out from 0.2 VL to 1.2 VL insteps of 0.2 VL | NA | The tan delta measurement carried out from 0.2 VL to 1.2 VL insteps of 0.2 VL |
| Inter turn Surge test | (1.7 * VL) kV | (1.7 * VL) kV | (1.7 * VL) kV | ||
| Ac high voltage test in kV | 1.3 X ( 2 X VL + 1 ) | 1.3 X VL | 1.3 X ( 2 X VL + 1 ) | ||
2 | Test before stator connection ( after coils insertion in wound stator) | Insulation resistance test | IR at 1 minute and 10 minute | IR at 1 minute and 10 minute | IR at 1 minute and 10 minute |
| Ac high voltage test in kV | 1.2 X ( 2 X VL + 1 ) | 1.2 X VL | 1.2 X ( 2 X VL + 1 ) | ||
| Insulation resistance | IR at 1 minute | IR at 1 minute | IR at 1 minute | ||
| Inter turn test – Surge in kV | (1.6 * VL) kV | (1.6 * VL) kV | (1.6 * VL) kV | ||
| RTD’s high voltage a.c | At 1.5 kv for 5 seconds | At 1.5 kv for 5 seconds | At 1.5 kv for 5 seconds | ||
| RTD’s resistance | Measure the resistance of all RTD | Measure the resistance of all RTD | Measure the resistance of all RTD | ||
3 | Test after stator connection with cables | Winding resistance | Resistance per phases at room temperature | Resistance per phases at room temperature | Resistance per phases at room temperature |
| Insulation resistance test | IR at 1 minute and 10 minute | IR at 1 minute and 10 minute | IR at 1 minute and 10 minute | ||
| Ac high voltage test in kV | 1.1 X ( 2 X VL + 1 ) | 1.1 X VL | 1.1 X ( 2 X VL + 1 ) | ||
| Insulation resistance | IR at 1 minute | IR at 1 minute | IR at 1 minute | ||
| Inter turn test – Surge in Kv | At 2 kV (Comparison with phases) | At 2 kV (Comparison with phases) | At kV (Comparison phases) | ||
| Tan delta and capacitance measurement | The tan delta measurement carried out from 0.2 VL to 1.2 VL insteps of 0.2 VL | NA | NA | ||
| RTD’s resistance | Measure the resistance of all RTD | Measure the resistance of all RTD | Measure the resistance of all RTD | ||
4 | Test after stator VPI (impregnation and post curing in hot chamber) | Winding resistance | NA | Resistance per phases at room temperature | Resistance per phases at room temperature |
| Insulation resistance test | IR at 1 minute and 10 minute | IR at 1 minute and 10 minute | |||
| Ac high voltage test in kV | 1. 05 X ( 2 X VL+ 1) | 1. 05 X ( 2 X VL + 1 ) | |||
| Insulation resistance | IR at 1 minute | IR at 1 minute | |||
| Tan delta and capacitance measurement | The tan delta measurement carried out from 0.2 VL to 1.2 VL insteps of 0.2 VL | The tan delta measurement carried out from 0.2 VL to 1.2 VL insteps of 0.2 VL | |||
| RTD’s resistance | Measure the resistance of all RTD | Measure the resistance of all RTD |
Where VL is The rated line voltage of the stator coil. The IR test for individual coils can be performed, if required.
Acceptance Criteria:
- Surge test – Rivera Standard Norms and IEC 60034-15 – Should not be short circuited between the turns and Windings
- AC HV test – Rivera Standard Norms and IEC 60034 & BS 499-5000 – Should not be failure in slot portion at specified voltage for duration of 1 minute
- Insulation Resistance (IR) and Polarization Index (PI) – IEEE 43 -2000 – The minimum value of IR 1 minute is 100 MΩ and PI 10/1minute is 2.5
- Tan delta test – IEEE 286 -2000 & IEC 60034-27-3
- At 0.2 * Un Dissipation factor should < 2 %
- Tan delta dissipation factor per 0.2 * Un should < 0.5%
- Dissipation factor tip-up between 0.6 * Un and 0.2 * Un should < 0.5 %
Electrical type test and testing standards
There shall be no voltage breakdown at 1.5 * VL + 1 for 30 seconds duration, 10% of total coils/bars
A voltage of 2 Un + 1 KV shall be applied for 1 minute between coil terminals and earth. The applied voltage shall then be increased at the rate of 1 kV/s up to 2 * (2*VL+1) kV, and then immediately be reduced at the rate of at least 1 kV/s to zero. There shall be no voltage breakdown during this sequence.
Impulse voltage withstand test on sample coils at 0.65 * (4 Un + 5 kV) with rise time of 0.2µs+/-0.1µs for five switching operation. The coils must withstand the impulse voltage
The coils/bars temperature rise from 40°C to 150° C and cooling from 150°C to 40°C for 500 cycles. During TCT tapping test, Tan delta test and PD measurements shall be repeated after 50,100,250 and 500 cycles.
The Voltage endurance test shall be performed on the coils/bars with schedule B.
The slot portion of the coils and bars from high voltage withstand test cut into equal lengths, then microscopic investigation and measuring of insulation thickness shall be performed.
The surface resistance of coils/bars 500 ohms to 5000 ohms/square
| Coils/bars line voltage | 6.6 kV | 11 kV | 13.2 kV | 13.8 kV | 15.75 kV |
| Test voltage in Schedule A (400Hours at 120°C) | 14.3 kV | 23.87 kV | 28.64 kV | 29.94 kV | 34.177 kV |
| Test Voltage in Schedule B (200Hours at 120°C) | 16.69 kV | 27.83 kV | 33.39 kV | 34.91 kV | 39.84 kV |
The standards used for testing are
- Inter turn test – Surge : IEC 60034-15
- AC High Voltage Withstand test : IEC 60034-15
- Tan delta and capacitance measurement: IEEE286-2000 and IEC 60034-27-3
- Insulation resistance measurement: IEEE 43-2000
- Partial discharge measurement: IEEE 1434-2014
- Thermal cycling test: IEEE 1310-2012
- Voltage endurance test: IEEE 1043-1996 and IEEE 1553