Applicable standards pertaining to switching surges
Consult Table 2 for the standards applicable to VCB switching surges.
Table 2 Applicable Standards Pertaining to Switching Surges
Circuit |
| Load type |
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|
breaker |
| Rotating |
| Dry type |
|
| When there is | Phase advance |
type |
| machine *1 |
| transformer | transformer |
| electronic | capacitor *4, *5 |
|
|
|
| (insulation | (insulation |
| equipment on |
|
|
|
|
| resistance | resistance |
| transformer |
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|
|
|
| below | class A) |
| low voltage |
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|
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|
| class A) |
|
| side |
|
Ordinary |
| Protected by CR |
| Protected by | No special |
| Protected by CR | 6.6 kV circuit: |
|
| suppressor *6 |
| surge | restrictions |
| suppressor *6 | No special |
|
|
|
| suppressor |
|
|
| restrictions |
|
|
|
|
|
|
|
| up to 300 kVA |
Low surge |
| No special |
| No special | No special |
| Protected by CR | 6.6 kV circuit: |
type |
| restrictions *2 |
| restrictions *3 | restrictions |
| suppressor *6 | No special |
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| restrictions |
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| up to 4000 kVA |
*1. | Mainly induction motors, but also includes synchronizing generators for private generator | |||||||
| equipment. |
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*2. | Use a CR suppressor for surge protection when inching at 55 kW (75HP) or below and on | |||||||
| inductance regulators. |
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*3. | Use an arrester for surge protection on circuits that require cutting off of excitation rush current. | |||||||
*4. | When the capacity of the group of capacitors exceeds 300 kVA, insert a series reactor (6%). | |||||||
*5. | For | |||||||
| as established in the standards for phase advance capacitors (JIS C 4801). |
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*6. | Table 3 shows the models of applicable CR suppressor. |
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| Table 3 CR Suppressors |
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| Circuit voltage |
| CR suppressor model |
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| 6.6 kV |
| NV60K304T1 |
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