● Protecting the loads from overload and phase failure
● Implementing short-circuit protection by means of a fuse or circuit breaker
● Used for the protection of motors
Instruction of type code
Technical specifications for assembled thermal relay of type 3SR8
Type | 3SR8-D13 | 3SR8-D23 | 3SR8-D33 |
Standard | IEC 60947-4-1 |
| Tripping class | 10 A |
| Rated working current Ie (A) | 25 | 36 | 93 |
| Setting range (A) | 0.1-25 | 23-36 | 23-93 |
| Rated insulation voltage Ui (V) | 690 |
| Rated impulse withstand voltage Uimp (kV) | 6 |
| Signalling Trip indicator | Trip indicator |
| Tightening torque (N·m) | 0.8 |
| Degree of protection | IP20 |
| Ambient air temperature (ºC) | -5 to +40, max. 95 % humidity |
| Storage temperature (ºC) | -40 ~ +75 |
| Maximum operating altitude (meters) | 2000 |
| Flame resistance | V1 |
| Mounting | Directly under the contactor |
Selection and ordering data
Series 3SR8
Mounting block
Action characterisitics for thermal relay 3SR8
Average operating time related to multiples of the current setting (Class 10 A)
Balanced 3-phase operation, from cold state
1. Setting: at lower end of scale
2. Setting: at upper end of scale
Balanced operation with 2 phases only, from cold state
Tripping curve for thermal relay 3SR8
1. Equilibrium running, 3 phase, start from cold state
2. Equilibrium running, 2 phase, start from cold state
3. Equilibrium running, 3 phase, after long period of setting current (hot state)
Outline and installation dimensions
Operating principle diagram of overload relay
English
