Lifetime expectancy and MTBF
| 3AC 400 V | 3AC 480 V |
|
|---|---|---|---|
Calculated lifetime expectancy1) | 69,000 h | 66,000 h | At 24 V, 40 A and +40°C |
86,000 h | 81,000 h | At 24 V, 32 A and +40°C | |
114,000 h | 112,000 h | At 24 V, 20 A and +40°C | |
196,000 h 1) | 186,000 h 1) | At 24 V, 40 A and +25°C | |
244,000 h 1) | 230,000 h 1) | At 24 V, 32 A and +25°C | |
322,000 h 1) | 316,000 h 1) | At 24 V, 20 A and +25°C | |
MTBF2) SN 29500, IEC 61709 | 375,000 h | 369,000 h | At 24 V, 40 A and +40°C |
685,000 h | 678,000 h | At 24 V, 40 A and +25°C | |
MTBF2) MIL HDBK 217F | 158,000 h | 157,000 h | At 24 V, 40 A and +40°C, Ground Benign GB40 |
211,000 h | 210,000 h | At 24 V, 40 A and +25°C, Ground Benign GB25 |
1) The calculated lifetime expectancy shown in the table indicates the minimum number of operating hours (service life) and is determined by the lifetime expectancy of the built-in electrolytic capacitors. The lifetime expectancy is stated in operating hours and is calculated according to the specifications of the capacitor manufacturer. The manufacturer of the electrolytic capacitors only guarantees a maximum service life of up to 15 years (131,400 h). Any number exceeding this value represents a calculated theoretical service life which can be used to compare devices.
2) MTBF stands for Mean Time Between Failure, which is calculated on the basis of statistical equipment failures and indicates the reliability of a device. It is the statistical representation of the probability of failure of a device and does not necessarily represent the service life of a product.
The MTBF number is a statistical representation of the failure probability of a device. For example, an MTBF number of 1,000,000 h means that statistically, if 10,000 devices are installed in the field, one device will fail every 100 hours. However, it is not possible to determine whether the failed device has run for 50,000 hours or only 100 hours.