Thermal Cutouts. Current sensitive thermal protection for coils/windings

Transcription

1 Thermal Cutouts Current sensitive thermal protection for coils/windings FEATURES broad product range for numerous applications rhomboid shape small size good pressure resistance high switching capacity minimal contact resistance temperature and current sensitive rapid response many approvals T-Type DESCRIPTION These thermal cutouts operate by means of a thermally sensitive bimetal snap-element which switches a double electrical contact when reaching a pre-set response temperature. They can be normally open or normally closed. The electrical current being switched flows through the bimetal element, which therefore gives a combination of temperatureand current-sensitivity. Heat transfer occurs on all sides via convection, radiation or conduction in gaseous or solid media. The rhomboid base conducts heat directly onto the bimetal element, allowing its use as a surface temperature cutout. APPLICATIONS Thermal protection, and under certain circumstances, temperature control of electrical machinery and equipment. Examples AC motors Coils Oil baths Single phase motors Electromagnets Water boilers DC motors Copiers Accumulators Generators Hot air dryers Liquid pumps Transformers Electric ranges Equipment of Rectifiers Washing machines different kinds Inverters DIMENSIONS T 10 (standard) T 11 (standard) T 21 (standard) Microtherm International Cooperation

2 TECHNICAL DATA Type T 10 * T 11 * T 20 * T 21 * Nominal voltage* Hz 250 V 250 V 250 V 250 V Current rating at cos ϕ = 1.0* 2.5 A 2.5 A 10.0 A 16.0 A Current rating at cos ϕ = 0.6* 1.6 A 1.6 A 6.3 A 10.0 A Max. load at cos ϕ = A 3.8 A 13.0 A 13.0 A 500 V Hz 3.5 A 3.5 A 380 V Hz 4.0 A 4.0 A 250 V Hz 6.3 A 6.3 A 16.0 A 20.0 A 110 V Hz 10.0 A A 20.0 A 25.0 A 60 V DC 1.0 A 1.0 A 2.5 A 6.3 A 42 V DC 1.2 A 1.2 A 4.8 A 8.0 A 6, 12, 24 V DC 1.5 A 1.5 A 6.3 A 10.0 A min. load 50 m A Contact normally closed arrangement normally open Switch operations at rated current EI (10.000) EI (10.000) 1E3 (1.000) 02E2 (200) contact resistance** 40 mω 40 mω 40 mω 40 mω response temperature range stepped in 5 C intervals +50 C to +180 C +50 C to +180 C +50 C to +160 C +65 C to +160 C tolerance ±3 K ±5 K ±10 K ±5 K ±10 K ±15 K ±2.5 K ±5 K ±10 K ±5 K ±10 K ±15 K Max. permanent temperature (standard) T 180 T 180 T 180 T 180 of switch mechanism* temperature rating of connecting leads by A. E. B. F. H A. E. B. F. H A. E. B. F A. E. B. F insulation class and 200 C max. 10 h 200 C max. 10 h 200 C max. 10 h 200 C max. 10 h epoxy sealant 230 C max. 5 h 230 C max. 5 h 230 C max. 5 h 230 C max. 5 h (to VDE 0530) Vacuum tightness standard. ref. P 102 standard. ref. P 102 standard. ref. P 102 standard. ref. P to to to to Leak rate bar cm 3 /sec bar cm 3 /sec bar cm 3 /sec bar cm 3 /sec Housing material Copper/Beryllium, stainless steel, rolled bronze, stainless steel, Coating material Teflon PTFE Hard epoxy Hard epoxy Hard epoxy Housing- SHB, SSB, SSH, SHB, SSB, SSH, HHB, SHB, SSB, HHB, SHB, SSB, Insulation options UWF, PTFE, SKH, GSS UWF, PTFE, SKH,. GSS SSH, UWF, VIB SSH, UWF, VIB Cross-section of the connecting leads 0.25 mm mm mm mm 2 standard version 1250 V Hz Insulation resistance/ P V Hz Dielectric strength P V Hz P V Hz P V Hz Nota: * Approved ratings. Further specific values on request, (U, V, B). Cycle rate 72/h. ** Contact resistance without connections, e. g. leads, wire or terminals. * The thermostats can be produced with a specific production mark * (e. g. letter V, U, B). L.S.C.T. 200 A 1 /2 hp UL 547. RESPONSE TEMPERATURES/TOLERANCE Temperature steps in 5 C intervals. Tolerance see Technical Data section, Clear-text indication of response temperature in C, tolerance in K. Switching hysteresis Reset occurs between 5 K and 50 K below response temperature, depending on response temperature and application. Rate of temperature change from 0.1 K/min. up to max. 1.0 K/min. The thermal cutout s response is affected by its insulation. For response time see page 4. The graphs on page 4 showing reset temperatures, current sensitivity, response time, give average values. Special switching temperatures are possible for better response and reset, if desired. For normally closed response <71 C the stated electrical load should be reduced by approx. 30 %; for normally open response temperatures <71 C reduce by approx. 60 %. This reduced loading is due to the combined temperature and current sensitivity of the device. 2

3 CONNECTIONS Type Temperature Lead length Designation class Cross section Sealing standard to VDE insulation Conductor Colour L510 B 0.25 mm 2 textile/lacquer copper tinned black T mm L517 F 0.25 mm 2 Polyolefin copper tinned blue L515 C 0.24 mm 2 PTFE copper silverplated white L520 B 0.5 mm 2 textile/lacquer copper tinned yellow T L531 F 0.5 mm mm Polyolefin copper tinned blue L528 H 0.5 mm 2 FEP copper tinned white L540 C 0.62 mm 2 PTFE copper silverplated white L523 B 0.5 mm 2 textile/lacquer copper tinned black T mm L531 F 0.5 mm 2 Polyolefin copper tinned blue L528 H 0.5 mm 2 FEP copper tinned white L560 B 0.75 mm 2 textile/lacquer copper tinned yellow T L569 F 0.75 mm mm Polyolefin copper tinned blue L575 H 0.75 mm 2 Silicone copper tinned white L567 C 0.75 mm 2 PTFE copper silverplated white K151 Clear text indication K 152 Code No. (Table on request). Insulation stripped: standard 6 ± 1 mm a = insulation stripped b = insulation stripped, but not removed c = insulation stripped, lead ends tinned Leads or solid wire in different lengths, cross-section and quality levels are available, see special data sheet. For production/technical reasons all types of leads are supplied in steps of 5 mm ±3 mm. The cutouts T 10 and T 11 can also be supplied in pairs or triplets. Lead and insulation dimensions on request. The temperature rating of the connection leads is at least equivalent to the response temperature of the cutout. Leads are specified according to insulation class and dielectric strength. PROTECTION units are sealed for use in oil, varnish, adhesive etc. Freon on request. CURRENT SENSITIVITY At higher loads, the response temperature of normally closed cutouts is lowered by a specific amount. See also page 4. Example for a normally closed T 11, 100 C: at 2 A load, the response temperature is lowered by 6.5 C on average. If a non-current sensitive cutout is required, please ask for data sheet No See also Technical Data section, page 2. tensile strength 60 N without functional impairment Other lead specifications available on request. HOUSINGS Various options are available on request. QUALITY STANDARD Production item testing Nominal response temperature Random sample quality testing: Life expectancy to VDE 0631 Function test to AQL 1.0 Measurement tolerance ±2 C AQL 4.0 Other values AQL INSULATION RESISTANCE/ DIELECTRIC STRENGTH Insulation housing to earth, if required up to across open contacts, depending on response temperature in special housings Inductive voltage please ask. APPROVALS 4000 V rms.ac 500 V rms.ac 4000 V rms.ac Life expectancy, nominal voltage and rated current as per VDE 0631/EN 60 73, see page 2. Other approvals obtained in many countries. Information on request.

4 RESPONSE TEMPERATURES FOR T 10/ T 11 CURRENT SENSITIVITY FOR T 10/ T 11 Alteration in switch-off temperature Series ± 3 K Series ± 5 K Series ±10 K T C ±6 K gives tolerance band of the switching temperature C Nominal temperature T 10 normally closed 100 C at 3 A load lowers the switch-off temperature by 11 C I Load (A) RESET TEMPERATURES FOR T 10/ T 11 RESPONSE TIME FOR T 10/ T 11 Reset temperature Overtemperature Average ambient temperature 12 C above switch-off temperature A T C with insulation sleeve switches after 1 min. without insulation with insulation T C ±6 K gives tolerance band for reset temperature of C Response time RESPONSE TEMPERATURES FOR T 21 CURRENT SENSITIVITY FOR T 21 Alteration in switch-off temperature Series ± 3 K Series ± 5 K T C ±6 K gives tolerance band for the switching temperature of C Nominal temperature T 21 at 8 A load lowers the switch-off temperature by 8 C I Load (A) RESET TEMPERATURES FOR T 21 RESPONSE TIME FOR T 21 Reset temperature Overtemperature Average ambient temperature 27 C above switch-off temperature. Without insulation sleeve switches after 0,5 min. T C ±6 K gives tolerance band for reset temperature of C without insulation with insulation Response time 4

5 INSULATION The standard versions of these cutouts are not insulated. If insulation is required, the standard type for the appropriate response temperature or continuous operating temperature (insulation class) should be chosen. Special versions are available, see separate data sheet. Insulation Type Insulation Description Class T 10, T 11 U 102 SHB, heat-shrunk B Polyester, transparent T 20, T 21 U 101 SHB, heat-shrunk B Polyester, transparent T 10, T 11 U 104 SSB, radiation cross-linked B black for normally closed U 108 red for normally open T 20, T 21 U 105 SSB, radiation cross-linked B black for normally closed U 109 red for normally open T 10, T 11 U 106 SSH, radiation cross-linked F transparent T 20, T 21 U 106 SSH, radiation cross-linked F transparent T 10, T 11 U 112 UWF epoxy coating F T 20, T 21 U 118 UWF epoxy coating F T 10, T 11 U 116 heat-shrunk PTFE/Teflon H/C T 10, T 11 U 168 Silicon coated glassfibre H sleeve T 10, T 11 U 182 SKH Insulation cap H Further insulations on request 5

6 MOUNTINGS Copper-Beryllium mounting clip for use with insulated (SSB, SSH, UWF, SKH) thermal cutouts. B 199 for types T 10, T 11 usable with insulation types U 112 U 168 U 182 INSTALLATION TIPS When installing thermal cutouts, it is important to ensure good heat transfer. The heat sensitive surface (base) should be placed in or near to the heat source. Heat conducting paste or paint will improve heat transfer. It should be noted that standard version thermal cutouts have a current-carrying housing, and that with electrically insulated cutouts the impaired heat transfer can alter the effective switching temperature. This should be borne in mind when selecting the nominal response temperature. See page 4 Response time. With single-phase motors, the cutout should switch the mains supply. It will then switch the motor off if there is any undesirable heating. The motor short circuit current will then be safely interupted, if this is larger than the current rating of the cutout. However, for a normally closed cutout, it should be appreciated that for higher currents, the response temperature is lowered, so that it can switch off without an external temperature rise. B 200 for types T 10, T 11 usable with insulation types U 104 U 106 U 108 U 116 For DC motors, the motor current will not be interrupted direct from the mains supply. The cutout installed in the windings should switch in series with the magnetic coil of the contactor. The electrical supply to the cutouts shold lead either singly or together from the motor terminals so that connection with the control circuit is possible. PRODUCT MARKING T11V Type, code letter Nominal response temperature (3 characters), tolerance ± in K (2 characters) 074E Month (2 characters), year (characters), country code CODING Normally closed (NC) = blue epoxy, code letter V Normally open (NO) = red epoxy, code letter F Special marking available on request. FIXING EXAMPLE ORDERING EXAMPLE Quantity Type Temperature Version 2000 T C ± 10 K U 102 We reserve the right to change specifications without prior notice. Company Address: Postal address: Phone +49 (0) Microtherm GmbH Microtherm GmbH Fax +49 (0) Täschenwaldstraße 3 P.O. Box 1208 Internet: D Pforzheim D Pforzheim mic-pforzheim@microtherm.de