270 Series
Thermal Switch
High Current, High Reliability Space
Honeywell's 270 Series High-Reliability Thermal Switch is the
Application Examples
result of years of meticulous engineering and continuous
•
Non-standard buss voltages: 42 VDC to 130 VDC
improvement. This product, originally developed for the
•
High current circuits @ 28VDC, 10 Amperes resistive
locomotive industry, is the standard for voltage and/or current
requirements exceeding MIL-PRF-24236 capabilities.
Features
The product line continues to evolve with the addition of new
•
All welded construction
standards. Off-the-shelf designs saves engineering resources,
•
OperatingTemp range of -85ºF to +300ºF
lead time, and expense by eliminating the need for customer
•
High Dielectric Withstanding Voltage (DWV)
•
500 cycles of run-in while monitoring contact resistance, 50
specifications.
These high-reliability switches are 100% micro-particle
analyzed, are visually precapped, and receive an extensive
milliohms maximum
•
Residual gas analysis
customers a product with the highest degree of workmanship
•
Crisp, snap-action contact operation
and reliability. Residual gas analysis and Group B testing are
•
Rugged construction, large glass seals, and large contacts
performed on every production lot.
•
Internal cleanliness 100% verified by micro-particle analysis
Upon testing and inspection Honeywell serializes each switch
•
Each switch serialized and shipped with individual test data sheet
acceptance test data. Commonly found on the Space Shuttle
•
Low contact resistance: 15 milliohms maximum
and International Space Station, these high quality units are
•
Hermetically sealed & backfilled with dry Nitrogen & Helium tracer
capable of handling 42 VDC and greater that are required by
•
Accommodation for 16 AWG and larger wires
the new power sources.
•
Group B Testing
battery of screening and acceptance tests. This assures
and completes an individual data sheet containing the
Large satellites, spacecraft, rocket boosters, life support
systems and experimental modules can all have high voltage
and/or high current needs. With a cycle life of over 100,000
cycles, the high reliability, hermetically sealed 270 SPACE
SERIES thermal switch is Honeywell's answer to the Space
Industry's ever-changing high-current requirements.
•
Space Station
•
Classified Defense Programs
No matter what your high-reliability application may be, Honeywell
has the right solution for your system.
Specifications for 270 Series Thermal Switches
Performance Characteristics
Contact Arrangement:
SPST
Contact Ratings:
3 amps resisitive load @ 55 VDC
Endurance:
100,000 cycles min. @ rated load
Dielectric Withstanding Voltage:
1250 VAC RMS - terminals to case, 500 microamperes maximum leakage
Insulation Resistance:
500 megohms min. @ 500 VDC - terminals to case
Environmental (MIL-STD-202)
Vibration (Sine):
Meth. 204, 15g 10 to 2000 Hz
Vibration (Random):
Meth. 214, 15g RMS
Ambient Temperature Range:
-85°F to 400°F (-65° to +204°C)
Moisture Resistance:
Meth. 106, 240 hrs., 90-98% RH, & from +77° +149°F (+25°C to 65°C)
Hermetic Seal:
Meth. 112, Cond. C, Procedure IV, 1.0 x 10-8 Atm, cc/sec max leak rate
Solderability:
Meth. 208
Shock:
Meth. 213, 100g/6ms, 750g/10ms
Thermal Shock:
Meth. 107, Cond. B, -85 to +257°F (-65°C to 125°C)
Acceleration:
Meth. 212, Cond. A, 30g
Salt Spray:
Meth. 101, Cond. B, 48 hours
Acceptance Test Data for 270 Series Thermal Switches
Contact resistance monitored burn-in
500 cycles min., 50, milliohms max
Random vibration
15g RMS
Particle impact noise detection (PIND)
No particle noise
Calibration/setpoint
3 cycles
Creepage (ARC) duration 3 cycles
<5msec, 1250 VDC
Seal:
fine leak: <1 X 10-8 Atm. cc/sec; gross leak: No bubbles
Contact resistnace - 3 cycles
15 milliohms max (6 VDC. 0.1A)
Dielectric withstanding voltage - Terminals to case
1250 VAC RMS - terminals to case, 60 Hz
Insulation Resistance - Terminals to case
500 megohms min. @ 500 VDC
Weight
Varies by configuration
Inspection of product
Final visual
Ordering Code
Tolerance Limits
Once written, your ordering code becomes
the specific part number, as this example
illustrates:
UNIT #
1
2
3
271 TL 150
4
5
6
A
160
XX
-65 to 250 (-54 to 121.1
±5 (2.8)
251 to 300 (121.7 to 148.9)
±7 (3.9)
Configuration shown in drawing
TL = Tin / Lead Plate
Lower temperature setpoint at 150°F ±5°F
A = Open on temperature rise
B = Close on temperature rise
Upper temperature setpoint at 160°F ±5°F
Custom features and temperature tolerances (consult factory)
UNIT 6 (see Ordering Code) may also be specified with a letter
and number code as shown below
Setpoint tolerances are min-max. Specify minimum differential
(example: A/7)
Opening setpoint is min or max. Specify closing tolerance and
minimum differential (example: B/5/7)
Closing setpoint is min or max. Specify opening tolerance and
minimum differential (example: C/5/7)
Lower, upper and minimum differential temperature tolerance
may be reflected as CLOSE TOLERANCE / OPEN
TOLERANCE / DIFFERENTIAL.
EXAMPLE: /5/5/7 where Close Tolerance = ±5°, Open
Tolerance = ±5°F, Differential = 7°F min.
Configuration Drawings
(dimensions in inches)
271
All configurations shown are available with upright terminals
WEIGHT: 27 grams max
272
WEIGHT: 43 grams max
.40
TYP
.41
.20
.20
TYP
3
4
2
1
4
3
1
2
1.07 HEX
1.05
.40
.20
1.01 MAX
.060 TYP
1.01 MAX
.050 TYP
.30 MAX
4X
.060
4X
.30 MAX
.050
.80 MAX
.21
.19
.65 MAX
TEMPERATURE
SENSING
SURFACE
.322
.302
3/8-24 UNF-2A
THREAD
274
WEIGHT: 71 grams max
3
4
2
1
275
WEIGHT: 43 grams max
.40
TYP
.20
TYP
2
3
1
4
1.01 MAX
.30 MAX
4X
.060
4X
.050
1.063
HEX
.65 MAX
.060
.98
3.812
3.375
.219 + .020
1.906
.06
TYP
.30
MAX
.05
TYP
.625
1.250
.80
MAX
4X 45°X.25
.218
R.109
.250 TYP
.200
.280
R.031
.190-32 UNF-2A
.210 MIN FULL THREAD
45° X .020 CHAMFER
276
WEIGHT: 43 grams max
270 Series Schematic
ISO-9001 Certification Since 1995
DISCLAIMER: Specifications are subject to change without notice. Honeywell reserves the right
to make changes to any product or technology herein to improve reliability, function, or design.
Honeywell does not assume any liability arising out of the application or use of the product.
Find out more:
www.thermalswitch.com
THERMAL SWITCHES exported from the United States must be done in accordance with the
Export Administration Regulations (EAR) and/or the International Traffic in Arms Regulations
(ITAR) as applicable.
Defense & Space Redmond
Honeywell International, Inc.
MAIL ADDRESS: P.O. Box 97001
15001 N.E. 36th Street
Redmond, Washington 98073-9701
PHONE: 888 206 1667
FAX: 425 883 2104
www.honeywell.com
TS270 EXP043 11/05
Copyright © 2004, Honeywell
International Inc. All Rights
Reserved. Printed in USA