For railway-applications, requirements for electrical and environmental operating-conditions, design requirements, construction and testing are defined in following main standards:
European Standard: EN 50155: 2017
International Standard: IEC 60571 2012
The requirements in these two standards are nearly identical, except for minor differences in terminology and definitions. Being more recently updated, the EN 50155-standard specifies some requirements more in detail.
| EN 50155 | IEC 60571 |
Operating temperature | Six operating temperature classes are defined: OT1-OT6 Short term thermal conditions are specified with the switch-on operating temperature classes: ST0-ST2 Test cycles A, B and C are defined to perform the dry heat test for above temperature classes and their combinations. | Seven ambient temperature classes are defined: T1-Tx Short term start up thermal conditions are defined in an additional column within above temperature classes.
No test cycles for dry heat test are defined. |
Interruptions of voltage supply | Three “interruption voltage supply classes” are defined: S1-S3 Specifies clearly that the interruption is caused by a short circuit of the DC supply distribution line and that the input voltage may reduce to 0 V. In this case, the DC distribution system presents a low impedance, which can cause reverse current from the device under test. | Two “interruption of voltage supply classes” are defined: S1-S2 No specification of type of interruption. |