AD Product Series (SnapStats)
Set Point Range: 0°F - 350°F

Contact movement is achieved using a bimetallic snap disk. Snap-action is a benefit to this product line, and broader differential is the important thermal characteristic.

CPI’s SnapStat thermal switches have a bimetal snap disc that actuates a miniature microswitch (see cross-section). This double snap action makes these switches virtually immune to shock and vibration. Epoxy sealing or glass to metal hermetic sealing makes them ideal for demanding industrial or military applications.

The SnapStat’s SPDT action provides both control and indication at the same time-two functions from one switch. Or it can be used as a SPST thermal switch. Calibration temperature range is 0°F to 350°F with a tolerance of +/- 7°F. (Dual temperature SnapStat incorporates two separate temperature controls in one mounting). The basic SnapStat switch mechanism is available under part number AD060 and is suitable for gluing or clamping in place. Custom brackets are also available.

UL recognized designs upon request.

AD Series Specifications

Calibration temp(factory set): 0°F Min. to 350°F Max. (Specify close on rise or close on fall).

Safe momentary undershoot/overshoot: -65°F to +400°F

Tolerance: ± 7°F (tighter tolerances available)

Repeatability: ± 3°F under standardized conditions

Actuation/Deactuation differential: 10°F to 25°F (non-adjustable)

Electrical Action: SPDT (standard), or SPST (specify NO or NC)

Electrical Rating:
Standard
28 VDC /120 VAC - 5 amp resistive, 3 amp inductive
220 VAC - 5 amp resistive

Gold contacts (for special applications, such as dry circuit or long periods of inactivity) - 28 VDC / 120 VAC, 1 amp resistive.

Endurance: 50,000 electromechanical cycles per standard electrical rating

Electrical Terminations: Leads are insulated from mounting, 20 AWG stranded, Teflon insulation. Special glass seal connections available.

Weight: 0.6 oz to 2.3 oz.

Response time per MIL s 24236 P4.7.5.1: From 15 secs. to 40 secs. (varies with thermal mass of switch body).

Qualification to MIL STD 810:
High Temperature		501.2 Proc. 1 Soak temp 350°F
Low Temperature		502.2 Proc. 1 -70°F
Humidity		507.2 Proc. 1
Salt fog		509.2 Proc. 1
Fungus		508.3 Proc. 1
Dust		510.2 Proc. I (Dust)
		510.2 Proc. II (Sand)
Shock Sawtooth		Application specific tests can be performed to meet customer requirements
Vibration		Application specific tests can be performed to meet customer requirements

 

Anatomy of the SnapStat

Click image for larger view

How CPI SnapStat Switches Work

When heat is applied to the bimetal disc, the disc reverses from concave to convex. This reversal of the disc operates a microswitch causing the normally open side to close and the normally closed side to open. When the disc cools, it reverts back to its normal condition, releasing the microswitch and reversing the electrical actions.

Bases of the SnapStats are thin for good heat conductivity and the ring supporting the snap disc is made of aluminum to help conduct the heat into the disc.

Applications for CPI SnapStat Thermal Switches

CPI SnapStat thermal switches offer a broad array of mounting, probe, and termination options for a diverse roster of industrial applications including over-temperature on air compressors, food extruders, distilling machines, escalators, and elevators.

CPI SnapStats are specified where reliability is critical. Applications include aircraft fuel systems, environmental control systems, medical equipment such as lasers, incubators, sophisticated electronic equipment including complex communication systems and fuel cells.

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Control Products, Inc • 280 Ridgedale Ave. • E. Hanover, NJ 07936 • (973) 887-9400 • E-mail: sales@cpi-nj.com
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