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Function :

Electronic Speed Switch is designed to evaluate the speed of a rotating object based on the speed information picked up by the non-contact type Inductive Proximity Switch. Output switches ON or OFF depending upon the process speed as compared to the set trip speed. Startup / Initial Bypass Delay (IBPD) facility is provided to bypass the under speed condition during startup. This allows safe time for the equipment to reach normal speed.

  Non-contact sensing.
  Extreme low speed & high speed detection.
  Programmable Set Points through keys.
  Input sensor selection facility: NPN or PNP or 2 Wire DC (NAMUR) type proximity switches can be used.
  Programmable Speed Range through keys.
  Programmable Initial Bypass delay (IBPD).
  2 C/O (2NO+2NC) relay contacts with programmable Relay Logic.
  6 digit, 7-segment LED display to indicate speed in RPM.
  User interface through keys.
  Programmable Hysteresis.
  ABS / Polycarbonate, IP-65 grade Enclosure for Monitor Unit.

Optional Features

  Programmable Trip Delay.
  4 – 20 mA output available.

Monitor Unit


: 110V AC / 230V AC, 50 Hz (Selectable) or 24V DC


: Pulses from Sensor Probe

Relay Logic

: Programmable. Various options are available


: a) 2 C/O (2NO+2NC) Relay Contacts
b) 4 -20 mA proportional to speed (optional)

Speed Range
(Speed Range in PPM can be computed as product of no. of actuations of the sensor per revolution & RPM of the rotating object)

: 1 – 6000 PPM (Higher range available on request)

LED Indication

: Pulses, Run Mode, Program Mode, LO & HI indication as per set point.

Start Up Bypass Delay

: 1 – 30 sec (Programmable)

Trip Delay (Optional)

: 1 – 30 sec (Programmable)

ON delay for Relay to become ON

: 1 – 180 sec (Programmable)

OFF delay for Relay to become OFF

: 1 – 180 sec (Programmable)


: 1 – 20% of set point (Programmable)

Relay Reset

: Auto / Manual (Programmable)


: 6 Digit, 7-segment, 0.3” Red LED display

Enclosure for Monitor

: ABS / Polycarbonate, dust and water tight to IP-65 grade suitable   for field mounting

Sensor Specifications:

Sensor Probe 1. Inductive Proximity Switch suitable for safe area (Non Hazardous)
2. 3 wire DC type / 2 wire DC NAMUR type
3. Supply voltage: 8V DC (Typical). Available internally through Monitor Unit
4. Enclosure: IP-67 grade. Tubular Threaded, Nickel chrome plated brass housing, with two nuts for clamping. Suitable for field mounting
5. Cable: 2 meter long integral PVC cable (Standard)
6. Size: Please refer Table ‘B’
Sensor Probe Selection 1. 2-wire probe (NAMUR)
2. PNP Probe
3. NPN Probe (Standard)

Table B: Status of Sensor Probe Details
Size (Thread Diameter) M18 M30 M36 M50 M80
Nominam switching distance (mm) for Non Flush Type 7mm 15mm 17mm 25mm 38mm
Nominam switching distance (mm) for Flush Type 5mm 12mm 14mm 20mm 32mm

Optional Accessories
Mounting bracket for Monitor Unit.
Mounting bracket for Sensor Probe.
IP-65 grade junction box with 4 nos. of Terminals.
Single or Double Compression Metallic (Brass) cable glands or PVC cable glands.
Sensing Flag.

Electronic Speed Switch is ideally suited to monitor any repetitive (i.e. rotational or translational) motion. It is best suited for the speed monitoring of material handling systems such as Belt Conveyors, Screw Conveyors, Bucket Elevators, Crushers, Drag Chains, Rotary Feeders etc.

Typical applications are:
To sense under speed or over speed conditions.
Detection of jamming in Feeders or Extractors.
Interlocking of conveyors.
Detection of chain link breakage in machines like Reclaimers, Drag Chain etc.
Motion detection.
Fan speed monitoring.
Missing bucket sensing in bucket elevators.