document number: 50024 revision 30- j an-02 www.vishay.com 78 rt, rte vishay sfernice for technical questions, contact sfer@vishay.com wirewound rheostats and potentiometers characteristics g z rheostat mode g z features 12w to 500w at 25c cctu 05-03b the performance of rt-rte rheostats exceeds the require- ments of speci cation cctu 05-03b. they have been designed for heavy duty applications such as repeated overloads, transients, shock and vibration con- ditions. rt vitreous series six si zes are available capable of dissipating 12, 25, 55, 100, 250 or 500 watts at 25 c. the resistive wire is protected by a proprietary vishay sfernice enamel red at high temperature and free from any compound that could cause corrosion of the wire. the maximum operating temperature of the rt series is 320 c. rte lacquered series the rte series covers high ohmic values but with a maximum operating temperature of 220 c. the rte versions have reduced power ratings except the rte 12 series. ganged units ganged units are available with different combinations of power and ohmic values (see data-sheet). graded windings these are recommended when the ratio is i max. > 2 i min. maximum overload in rheostat use, the winding current decreases in relation to the number of turns being used. when part of the winding is used the current can be increased in accordance with the graph on the left. substantially heavier overloads can be applied in short impulses and we would be pleased to advise on this type of application, on receipt of the following information : proposed rheostat usage current level operating cycles specifying duration of overload on , off periods. potentiometer mode % winding in service current increase factor over nominal 1.28 1.24 1.20 1.16 1.12 1.08 1.04 1 0 15 30 45 60 75 90 100
www.vishay.com 79 rt, rte vishay sfernice document number: 50024 revision 30- j an-02 for technical questions, contact sfer@vishay.com wirewound rheostats and potentiometers characteristics rt25 0 rt55 0 rt100 rt230 rt500 other special features are available. please consult vishay sfernice for all of your rheostat requirements. all the positionings are de ned when the shaft end is viewed (contrary to the above windings) clockwise detent. double mini switch for series and size 219410 219430 219450 219470 219480 29 33 33 35 35 code l mm dimensions c b a c b a c b a c b c idle lug idle lug c b a c b a c b a off position left code no.: 213700 off position right code no.: 213600 fixed tappings, one or more code no.: rtp not available for rt12 and rt500 idle lug left code no.: db1 not available for rt12 and rt500 idle lug right code no.: db2 not available for rt12 and rt500 reduced left travel not available for rt12 and rt500 reduced right travel not available for rt12 and rt500 double mini switch not available for rt12 special features l
document number: 50024 revision 30- j an-02 www.vishay.com 80 rt, rte vishay sfernice for technical questions, contact sfer@vishay.com power rating chart temperature rise nominal dissipation in watts temperature rise at hottest point c 350 300 250 200 150 100 50 0 1 5 10 100 1000 rt 12 rt 25 rt 55 rt 100 rt 230 rt 500 ambient temperature in degrees celsius % rated power 100 75 50 25 0 0 50 100 150 200 250 300 350 rt rte wirewound rheostats and potentiometers characteristics optional winding model rt rte style 230 optional a model acc knob dial 60jf cg115 special features idle lug left db1 method n optional 10k ? as il special, please supply a drawing tolerance 10% option vitreous lacquered shaft locking device variation law command shaft ohmic value special design ordering information
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