meter instrument overvoltage protection ptc thermistor-九游会下载

brief introduction:

mz31 series of ptc thermistor is a million- time safety thermistor of automatic circuit protection,recoverability, using repeatedly, and no trigger, 

noise or protective component that could protect and restore from abnormal temperature and current automatically,which called "auto restore fuse" and 

"ten-thousand-time fuse".recoverability, using repeatedly, and no trigger, noise or sparks. it can replace traditional fuse and widely applied 

in overvoltage protection and overload protection of motor, transformer, electronic circuit. ptc thermistor decreases its residual current through 

sharp resistance increasing, restraining consumption of the whole line,and it can restore its protective function after the trouble was removed.

but traditional fuse could not restore after fusing in the circuit.

applications:

overvoltage protection,overload protection of electronic meter and instrument,multimeter, kilowatt-hour meter and electronic circuit.

working principle:

as indicated in fig as below,when circuit is in the normal state, the current through ptc thermistor is lower than the rated current and ptc thermistor 

is in the normal state with small resistance value,which will not affect the normal operation of the protected circuit such as primary and secondary loops 

of the voltage transformer.in case of some trouble in the circuit and the current is bigger than the rated current,the ptc thermistor will become hot 

quicklyand present high resistance value, which sets the circuit relatively “off” to protect the circuit from damage.after the trouble is removed,ptc thermistor

will automatically restore its low resistance state and the circuit will resume normal operation.

advantages:

1.automatic circuit protection,can resume steadily after circuit protection,

2.contactless,noiseless and flameless;

3.reacts fast

4.long stability

5.with a better performance of overvoltage protection,

   suitable for operating in  265/420/550v ac (high resistance state) continuously

6.rohs compliant. 

choose guidelines :

in selecting ptc thermistor as overvoltage protection component,firstly,make sure of the maximum operating current in the circuit(non-trip current 

of ptc thermistor) and maximum operating voltage,rated zero power resistance,and also the outlook and dimension should be also taken into consideration.

marking of part number:

1.series:ptc thermistor for overvoltage protection,overload protection

2.type:1-disc,2-encased,3-pin form-coating,4-pin form non-coating,5-smd

3.type:voltage level:h-550/420/265/250v     m-140v            l-30/60v

4.chip size: 08-φ8mm          09-φ9mm         11-φ11mm      

5.curie temperature: f-50℃       h-80℃       n-100℃   p-120℃     k-125℃

6.r25 resistance: 6r0-6ω     6r5-6.5ω      70r-70ω      121-120ω 

7.resistance tolerance: k /-10%        m /-20%         h /-25%         n /-30%

8.greatly voltage:265-265v       550-550v

9.wire shape: s-straight, a-axis formed, u-in-formed

dimension(unit: mm):

specification&part no.: