1. Speed Switches
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2. NSS How it Works
Sensor disc is attached to rotating shaft that is
being monitored
Sensor disc has magnets in it that creates an
alternating magnetic field
Sensor is mounted across from disc and detects
magnetic field changes as a frequency

3. NSS How it Works
The switch decodes the magnetic frequency
signal to calculate a rotation speed in RPM
The switch compares the present speed to that
of the set point
Switch is activated according to set up for under
speed, over speed, or no speed

4. NSS
Two ranges: 10 to 100 RPM and 100 to
5000 RPM
Set point can be set anywhere in the
range
SPDT switch rated 5A @ 115 VAC
Temperature Limits: -40 to 140°F (-40 to
60°C)
Comes pre-wired with 12” (30.5 cm) of 18
AWG

5. NSS
Power Requirement: 115 VAC
Gap Distance: 3/8”(9.5 mm) ±1/8” (3.1
mm)
Conduit Entrance: 1” female NPT

6. Non-Contact vs Contact
The sensor is not connected to the
rotating shaft
No worries about bearings to wear out
No mechanical linkages to wear out or
break
Easier to install then direct couple types
as alignment is not as critical

7. NSSM
Metal housing
Explosion-proof
UL pending
Can come in kit with
disc or with disc
separate

8. NSSP
Plastic housing
NEMA 4X
Disc comes
separately

9. Discs and Mounting Brackets

10. NSS Applications
Drive trains
Crushers
Belt conveyors
Bucket elevators
Exhaust fans
Screw conveyors
Tail pulleys
Looking for belt breaks, slippage, clogs,
overloads, failures

11. Turbine Protection
Application: Westinghouse AC Vertical 2900 KW
Generator
Problem: Shaft (300 rpm) for Electric Grid Transfer
Customer: Duke Energy – Gaston Shoals, SC

12. Turbine Protection
Application: General Electric 1798 KW AC Vertical
Generator
Problem: Shaft (300 rpm) for Electric Grid Transfer
Customer: Duke Energy – Gaston Shoals, SC

13. Coal Feed – Ratio Metric Conveyor
 Precise coal feed control to furnace
 Protect against feeder clogging
 Protect against machine failure
 Maintain operational efficiency

14. Coal & Ash Conveyor Monitoring
Belt breakage or slippage detection
Conveyor slow-down or stoppage
Under/over speed detection

15. Boiler Feed-Water Pump Protection
 Protect high service pump shafts from shaft reversal
 Avoid costly equipment damage caused by reverse water
flow
 Rugged & reliable system
 Easy installation & set up
 Cost effective pump protection

16. Screw Conveyor
Application: Screw Conveyor – Harsh environment
Problem: Detect slow-down or zero speed of conveyor
Customer: Industrial Grain Processor

17. Rotary Airlock
Application: Rotary air lock – Harsh environment
Problem: Detect slow-down or zero speed
Customer: Industrial application

18. Industrial Mixer
Application: Industrial Mixer – Harsh environment
Problem: Detect slow-down or zero speed

19. Bucket Elevator
Application: Grain - Bucket Elevator
Problem: Conveyor slow-down. Prevent possible
spark/explosion or product waste
Customer: Grain/Feed/Ethanol facility

20. Blower Monitoring
Application: Industrial heat treating machinery –
Blower monitoring
Problem: If belt breaks or motor stops toxic fumes
build up – possible fire hazard
Customer: Industrial heat treating oven OEM and/or
end user

21. Oven Fan & Conveyor
Application: Mesh Belt Furnace
Problem: Conveyor & fan speed detection
Customer: Surface Combustion – Oven OEM

22. Heat Treating
Application: Monitor motor shaft speed
Problem: Maintain Consistent conveyor speed and air
flow
Customer: Thermal systems – Heat treating/drying

23. Conveyor Speed
Application: Municipal Treatment Conveyor Speed
monitoring
Problem: Speed change can cause material backup and
systems damage
Customer: City waster water treatment facility

24. Mixer
Application: Material Processing Mixer - Agitator Speed
Control
Problem: Varying material volume requires varying
agitation speed Sensor
Customer: Mixer/centrifuge
OEM & user

25. Conveyor Protection – Slow Down/Zero Speed
•Applications: Grain/Feed, Cement/Aggregate, Mining,
Packing, Paper, Textile, etc.
•Senses belt slippage, slow-down and/or zero speed
•Simple, low-cost machine protection
•Provides early warning & prediction maintenance
•Increased efficiency, increased productivity, reduced
down-time, etc.

26. Automobile Conveyor
Application: Fixtured chain conveyors for controlling line
speed on automotive assembly lines.
Problem: Conveyor over speed (a.k.a. runaway or
break away speed) can cause chassis collision,
possibly causing severe damage and/or injury.

27. Garbage Shredder
Application: Conveyor speed monitor – garbage
shredder
Problem: conveyor speed fluctuations are critically
monitored

28. Rock Quarry
Application: Rock quarry and/or
cement plant
Problem: Conveyor slow-down.
Possible spark & Explosion, and or
loss of production

29. Questions
To order a free catalog or for more information contact;
Dwyer Instruments, Inc., P.O. Box 373,
Michigan City, IN., 46361
Telephone: (800) 872-9141 or (219) 879-8000
Fax: (219) 872-9057
Internet address: www.dwyer-inst.com
E-mail: info@dwyer-inst.com