860-928-6551 Brooklyn, Connecticut


Stop an entire operation if one machine fails.

8100 Series Zero Speed Switch

Operating Range: 0.5 to 25 RPM

The 8100 Series Zero Speed Switches are deal for slow speed applications. They are electromechanical rotary motion controls requiring no electrical input to operate. These shaft-driven devices can let you know if equipment is running too fast, too slow, or not at all.

These UL-approved speed switches can be interlocked as part of a conveyor system to ensure that if one machine fails, the entire operation will stop, avoiding an expensive and time-consuming pile-up of material.

  • For shaft input speeds of 0.5 to 25 RPM.
  • Will operate in temperatures ranging from -40° F to +250° F (-40° C to +482° C).
  • NEMA 4/4X housings are painted with an epoxy-based powder coat to provide corrosion resistance, as well as protection against dust, rain and hose-directed water.

Speed Switch devices coupled to a corresponding shaft, must be properly mounted and aligned to avoid putting extra load on motor bearings, which may cause premature failure. The use of installation accessories such as Mounting Brackets and K-Couplings provide a secure foundation and eliminate misalignment connection problems. Need assistance choosing the appropriate speed switch? Fill out the Application Data Sheet and a Sales Engineer will help determine which switch is right for your specific application. Dazic® Application Data Sheet

8100 Series
Driver Shaft-to-Shaft
Shaft Diameter 1/2″ (1.27 cm)
Operating Range 0.5 to 25 RPM
Driver Torque Required .0208 ft-lb (4 in-oz) (.0282 Nm)
Temperature Tolerance -40°F to +250°F (-40°C to +121°C)
Housing Options Aluminum (AL) or Cast Iron (CI)
NEMA Rating 4/4x
Mounting Options Base Flange or Flange with Pilot
Dimensions (L x W x H) 6.02″ x 4.25″ x 3.93″ (15.29 cm x 10.80 cm x 9.98 cm)
Wiring Contact Options SPDT, DPDT, SPDT(2)
Weight AL – 4 lbs. (1.81 kg)      CI – 8 lbs. (3.63 kg)

Not Field Adjustable

Speed Switch Input (RPM) (Application Running Speed) Approximate Contact Operating Speeds (RPM) Contact Type
Start-Up Trip-Point Upon Initial Speed Switch Acceleration (RPM) Drop-Out Point On Shaft Speed Loss (RPM) SPDT Single Pole, Double Throw DPDT Double Pole, Double Throw SPDT(2) Direction Indicating
1.5 5 1.5 0.5 RPM 0 RPM 8121 81212 8131
0.5 2.5 0.5 Approx. 4 Sec. After Shaft Rotation Failure 8121-5 81212-5 8131-5
2 25 1.5 Approx. 3-5 Sec. After Shaft Rotation Failure 8121-5 81222-5 8132-5

Swtiches can be mounted in any position but they must be aligned and concentric with the corresponding drive shaft. When ordering, please specify Mounting Style: Type B – Base Mount Type F – Flange Mount Type FK – Flange Mount w/ pilot

How To Order

Housing Material Model No. Mounting Style
(AL or CI)   81xx-xx   (B, F, or FK)

For example: Model 8121-5 with Cast Iron housing and Base mount = CI-8121-5-B

Dazic 2120 series
Model 8120 with Base mount (Type B)

Dazic 2120 with flange
Model 8120 with Flange mount with pilot (Type FK)


Single Pole, Double Throw

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Double Pole, Double Throw

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Direction Indicating

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