Temperature measurement
Probe assemblies
B57227K
K227
Applications
Electric motors
Transformers
Features
Coated thermistor disk with shrunk sleeve
insulation
PTFE-insulated wires, AWG 26
UL approval (E69802)
Options
Alternative resistance ratings, rated
temperatures, resistance tolerances and wire
lengths available on request.
Delivery mode
Bulk
General technical data
Climatic category
Max. power
Resistance tolerance
Rated temperature
Dissipation factor
Thermal cooling time constant
Heat capacity
Insulation resistance
Test voltage
(IEC 60068-1)
(at 25
°C)
Dimensional drawing
Dimensions in mm
Approx. weight 5 g
(in air)
(in air)
(V = 100 V DC)
(t = 1 s)
P
25
∆R
R
/R
R
T
R
δ
th
τ
c
C
th
R
ins
V
test
55/155/56
200
±10
100
approx. 5
approx. 30
approx. 150
> 100
2.5
mW
%
°C
mW/K
s
mJ/K
MΩ
kV AC
Electrical specification and ordering codes
R
100
Ω
1.8 k
R
25
Ω
32762
No. of R/T
characteristic
2904
B
25/100
K
4300
±3%
Ordering code
B57227K0333A001
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 2 of 9
Temperature measurement
Probe assemblies
B57227K
K227
Reliability data
Test
Storage in
dry heat
Standard
IEC
60068-2-2
Test conditions
∆R
25
/R
25
(typical)
< 2%
Remarks
No visible
damage
Storage in damp
heat, steady state
Rapid temperature
cycling
Endurance
Long-term stability
(empirical value)
Note
Storage at upper
category temperature
T: 155
°C
t: 1000 h
IEC
Temperature of air: 40
°C
60068-2-78 Relative humidity of air: 93%
Duration: 56 days
IEC
Lower test temperature: 55
°C
60068-2-14 Upper test temperature: 155
°C
Number of cycles: 10
P
max
: 200 mW
t: 1000 h
Temperature: 100
°C
t: 10000 h
< 1%
No visible
damage
No visible
damage
No visible
damage
No visible
damage
< 1%
< 2%
< 3%
Contact of NTC thermistors with any liquids and solvents shall be prevented. It must be
ensured that no water enters the NTC thermistors (e.g. through plug terminals).
Avoid dewing and condensation unless thermistor is specified for these conditions.
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 3 of 9
Temperature measurement
Probe assemblies
B57227K
K227
Cautions and warnings
See "Important notes".
Storage
Store thermistors only in original packaging. Do not open the package prior to storage.
Storage conditions in original packaging: storage temperature 25
°C
... +45
°C,
relative
humidity
≤75%
annual mean, <95% maximum 30 days per annum, dew precipitation is
inadmissible.
Do not store thermistors where they are exposed to heat or direct sunlight. Otherwise, the
packing material may be deformed or components may stick together, causing problems during
mounting.
Avoid contamination of thermistor surface during storage, handling and processing.
Avoid storage of thermistors in harmful environments like corrosive gases (SO
x
, Cl etc).
Use the components as soon as possible after opening the factory seals, i.e. the
polyvinyl-sealed packages.
Solder thermistors within the time specified after shipment from EPCOS.
For leaded components this is 24 months, for SMD components with nickel barrier termination
12 months, for SMD components with AgPd termination 6 months.
Handling
NTC thermistors must not be dropped. Chip-offs or any other damage must not be caused
during handling of NTCs.
Do not touch components with bare hands. Gloves are recommended.
Avoid contamination of thermistor surface during handling.
Washing processes may damage the product due to the possible static or cyclic mechanical
loads (e.g. ultrasonic cleaning). They may cause cracks to develop on the product and its parts,
which might lead to reduced reliability or lifetime.
Bending / twisting leads
A lead (wire) may be bent at a minimum distance of twice the wire’s diameter plus 4 mm from
the component head or housing. When bending ensure the wire is mechanically relieved at the
component head or housing. The bending radius should be at least 0.75 mm.
Twisting (torsion) by 180° of a lead bent by 90° is permissible at 6 mm from the bottom of the
thermistor body.
Soldering
Use resin-type flux or non-activated flux.
Insufficient preheating may cause ceramic cracks.
Rapid cooling by dipping in solvent is not recommended.
Complete removal of flux is recommended.
Please read
Cautions and warnings
and
Important notes
at the end of this document.
Page 5 of 9
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