860-928-6551 Putnam, 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
Driver Shaft-to-shaft
Shaft Diameter 1/2″ (1.27 cm)
Operating Range 4 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 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″ x 4-1/4″ x 3-15/16″ (15.29 cm x 10.80 cm x 9.53 cm)
Wiring Contact Options SPDT, DPDT, SPDT(2)
Weight AL – 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 Throw DPDT Double Pole, Double Throw SPDT(2) Direction Indicating
24 2000 14 to 19 10 RPM 0 RPM 2120 2122 2130
15 200 8 to 11 Approx. 2 Sec. After Shaft Rotation Failure 2120-1 2122-1 2130-1
8 100 5 to 7 Approx. 3 Sec. After Shaft Rotation Failure 2120-5 2122-5 2130-5
4 50 2 to 3 Approx. 5 Sec. After Shaft Rotation Failure 2120-10 2122-10 2130-10
30 2000 25 to 70 30-40% Below Trip Point 0 2120-A1 2122-A1 2130-A1
75 2000 60 to 140 30-40% Below Trip Point 0 2120-A2 2122-A2 2130-A2
150 2000 125 to 300 30-40% Below Trip Point 0 2120-A3 2122-A3 2130-A3
240 2000 200 to 600 30-40% Below Trip Point 0 2120-A4 2122-A4 2130-A4
15 200 10 to 45 30-40% Below Trip Point 0 2120-A11 2122-A11 2130-A11
7 100 5 to 15 30-40% Below Trip Point 0 2120-A15 2122-A15 2130-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 Material Model 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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