860-928-6551 Brooklyn, Connecticut


Stop an entire operation if one machine fails.

2100 Series Zero Speed Switch

Operating Range: 4 to 2000 RPM

The 2100 Series Zero Speed Switches 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 material handling 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 4 to 2000 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

2100 Series
Shaft Diameter1/2″ (1.27 cm)
Operating Range4 to 2000 RPM
Driver TorqueRequired.0208 ft-lb (4 in-oz) (.0282 Nm)
Temperature Tolerance-40°F to +250°F (-40°C to +121°C)
Housing OptionsAluminum (AL) or Cast Iron (CI)
NEMA Rating4/4x
Mounting OptionsBase, Flange or Flange with pilot
Dimensions (L x W x H)6″ x 4-1/4″ x 3-15/16″ (15.29 cm x 10.80 cm x 9.53 cm)
Wiring Contact OptionsSPDT, DPDT, SPDT(2)
WeightAL – 4 lbs. (1.81 kg)      CI – 8 lbs. (3.63 kg)
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 ThrowDPDT Double Pole, Double ThrowSPDT(2) Direction Indicating
24200014 to 1910 RPM0 RPM212021222130
152008 to 11Approx. 2 Sec. After Shaft Rotation Failure2120-12122-12130-1
81005 to 7Approx. 3 Sec. After Shaft Rotation Failure2120-52122-52130-5
4502 to 3Approx. 5 Sec. After Shaft Rotation Failure2120-102122-102130-10
30200025 to 7030-40% Below Trip Point02120-A12122-A12130-A1
75200060 to 14030-40% Below Trip Point02120-A22122-A22130-A2
1502000125 to 30030-40% Below Trip Point02120-A32122-A32130-A3
2402000200 to 60030-40% Below Trip Point02120-A42122-A42130-A4
1520010 to 4530-40% Below Trip Point02120-A112122-A112130-A11
71005 to 1530-40% Below Trip Point02120-A152122-A152130-A15

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 MaterialModel No.Mounting Style
(AL or CI) 21xx-xx (B, F or FK)

For example: Model 2120-1 with Cast Iron housing and Base mount = CI-2120-1-B

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

Dazic 2120 with flange
Model 2120 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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