SZ1 - Thermal-Protectors with insulation cap
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Information 392e Defined Current Sensitive Thermal protector of Type SZ1 Application: The current sensitive thermal protector type SZ1 with normally closed contacts is utilised for overheating protection of all electric equipment or devices, especially to safeguard transformers according to EN 60 742. The type SZ1 is sensitive for temperature as well as for currents. Therefore it is recommended in all cases of a dramatic rise of temperature, due to an overload current, e.g. in case of short circuit. Design: The thermal protector SZ1 is based on the well proven mechanism of Thermik’s product series 01. A defined current-sensitivity is reached by an integrated series resistor RS. Version: SZ1 with insulation cap Length of insulation cap l dimensions (average) Operation: If, in the case of overheating or increase in current, the rated switching temperature of the bimetallic disc is reached, this suddenly snaps over and opens the contact. Automatic resetting after a significant temperature drop. The series resistor RS has to be adapted to each application. To protect an electrical apparatus, the response time should be less than 20 seconds in case of a short circuit. In order to guarantee this ideal response time, a heating performance of RS between 5 W and maximal 10 W is recommended. The table on the next side will help to find an optimal resistor RS. Due to different possibilities of adapting the protector to the electrical device, experimental tests with different protectors are recommended. Features: Quick response sensitivity Defined response time Excellent long term performance Instantaneous switching Very short bounce times Temperature resistance : featured by the metal housing and small protector mass : < 20 s , due to series resistor RS : due to fine-silver contacts. Reproducible switching temperature values due to tempered, electrically and mechanically unstressed bimetallic disc : with constant contact pressure over the whole temperature range : < 1 ms : by use of high temperature resistant materials and components

NC – normally closed – 70 ° - 160 ° C C in steps of 5 K ± 5K > 35° C 250 V AC (VDE) other values upon request 2.0 A cos φ = 1.0 ; 1.6 A cos φ = 0.6 (depending on series resistor RS) 4.0 A cos φ = 1.0 3,000 switching cycles (depending on series resistor RS) Yes < 1 ms suitable (according to Thermik-test) < 50 mΩ (without series resistor RS) with reference to MIL–STD. R 5757 100 m/s² Adapted to each application (see table) Recommended heating performance in case of short circuit: 5 W - 10 W insulation cap: Mylar – Nomex ® ®Trade mark Du Pont 2 kVr.m.s. 2 multi strand wire 0.25 mm , length 100...