Passive Magnetic Speed Pickups
Passive Magnetic Speed sensors are simple, rugged devices that don’t require any external power to operate. A permanent magnet in the sensor establishes a fixed magnetic field and passing a ferrous metal target (gear) near the sensor’s pole piece (sensing area) changes the flux lines of the magnetic field, dynamically changing its strength.
This change in magnetic field strength induces a current into a coil winding which is attached to the pickups output terminals. The output signal of the sensor is an ac voltage that varies in amplitude and wave frequency as the speed of the monitored device changes, and is usually expressed in peak to peak voltage (Vp-p).
One complete waveform (cycle) occurs as each target passes the sensor’s pole piece. If a standard gear were used as a target, this output signal would resemble a sine wave if viewed on an oscilloscope.
High Output sensors are designed for use in applications where higher output voltages are needed. They perform best at low to medium speeds with medium to high impedance loads. Front-End Sealed versions are available for use where the sensor is exposed to fluids, lubricants or adverse environmental conditions.
The TS300 self-powered digital governor is designed to control an API-611, single valve, general purpose steam turbine driving a mechanical load. For applications where 24 vdc power is not available the TS300 can be operated in self-powered mode; where the power used to run all of the TS300 electronics is generated from two speed probes. The TS300 also makes use of a back-up battery, providing power when the turbine is stopped or operating at low RPM in the self-powered configuration. The TS300 can also be used for simple turbine applications where 24vdc power is available.
APPLICATIONS
- Engine RPM (revolutions per minute) measurement on aircraft, automobiles, boats, buses, trucks and rail vehicles
- Process speed measurement on food, textile, paper, woodworking, printing, agriculture, and pharmaceutical industry machinery
- Motor speed measurement of electrical generating equipment
- Speed measurement of pumps, blowers, mixers, exhaust and ventilating fans
- Flow measurement on turbine meters
- Gear speed measurement
FEATURES
- Self-powered for remote / isolated applications
- Direct conversion of speed to output frequency
- Simple installation, No moving parts
- Designed for use over a wide range of speeds
- Adaptable to a wide variety of configurations
- Customized VRS products for unique speed sensing applications
- Housing materials/styles: stainless steel threaded or smooth
- Output voltages: 8 Vp-p to 190 Vp-p
| Model Number | 7121-0000 | 7125-0000 | 7131-0001 |
|---|---|---|---|
| Description | Std – 5/8-18 x 2.218″ (1.125″ threads) | LR – 5/8-18 x 5.093″ (4.00″ threads) | Std – 5/8-18 x 6.107″ (5″ threads) |
| Diameter | 15.9 mm [0.625 in] | 15.9 mm [0.625 in] | 15.9 mm [0.625 in] |
| Housing Length | 56 mm [2.20 in] | 130 mm [5.10 in] | 156 mm [6.10 in] |
| Weight | 70 g [2.5 oz] | 98 g [3.5 oz] | 128 g [4.5 oz] |
| Feature | Description |
|---|---|
| Output Voltage (Peak to Peak) Min. | 190 Vp-p |
| Pole Piece Shape and Size | Round, 2.69 mm [0.106 in] Dia. |
| Operating Temperature | -55 °C to 120 °C [-67 °F to 250 °F] |
| Gear Pitch Range | 24 DP (Module 1.06) or Coarser |
| Operating Frequency | 15 kHz |
| Inductance | 450 mH |
| Coil Resistance | 910 Ohm to 1200 Ohm |
| Surface Speed | 0.25 m/s [10 in/s] |
| Optimum Actuator | 20 DP (Module 1.27) Ferrous Metal Gear |
| Mounting Thread | 5/8-18 UNF-2A (M16 Metric Thread Available) |
| Vibration | MIL-STD 202F, Method 204D |
| Material | Stainless Steel Threaded |
| Termination | MS3106 Connector |
| Model Number | 7120-0000 | 7130-0000 | 7131-0503 | 7131-0000 |
|---|---|---|---|---|
| Description | Std: 3/4-20 x 3.125″ (1.875″ threads) | LR: 3/4-20 x 4.75″ (3.5″ threads) | 5/8-18 x 3.050″ (1.8″ threads) | 5/8-18 x 4.75″ (3.5″ threads) |
| Diameter | 19.5 mm [0.750 in] | 19.5 mm [0.750 in] | 15.9 mm [0.625 in] 15 | 15.9 mm [0.625 in] |
| Housing Length | 78 mm [3.05 in] | 122 mm [4.80 in] | 78 mm [3.05 in] | 122 mm [4.80 in] |
| Weight | 294 g [10.5 oz] | 322 g [11.5 oz] | 280 g [9.0 oz] | 366 g [10.0 oz] |
| Feature | Description |
|---|---|
| Output Voltage (Peak to Peak) Min. | 60 Vp-p |
| Pole Piece Shape and Size | 4.75 mm [0.187 in] Diameter |
| Operating Temperature | -73 °C to 93 °C [-100 °F to 200 °F] |
| Gear Pitch Range | 12 DP (Module 2.11) or Coarser |
| Operating Frequency | 40 kHz |
| Inductance | 115 mH |
| Coil Resistance | 191 Ohm to 280 Ohm |
| Surface Speed | 0.38 m/s [15 in/s] |
| Optimum Actuator | 8 DP (Module 3.17) Ferrous Metal Gear |
| Mounting Thread | 3/4-20 or 5/8-18 UNF-2A |
| Vibration | MIL-STD 202F, Method 204D |
| Material | Stainless Steel Threaded |
| Termination | 24 AWG PVC-Insulated Leads, 3000 mm [120 in] |
| Test Conditions | Surface Speed = 25 m/s [1000 in/s], Gear = 8 DP (Module 1.27), Air Gap = 0.127 mm [0.005 in], Load Resistance = 100 kOhm |
| Feature | Description |
|---|---|
| Description | HO: 5/8-18 x 5.093″ (4.0″ threads) |
| Diameter | 0.140 in |
| Housing Length | 5.093 in |
| Weight | 128 g [4.5 oz] |
| Output Voltage (Peak to Peak) Min. | 9.2 Vp-p |
| Operating Temperature | -65 °F to 220 °F |
| Inductance | 87 mH Typical |
| Coil Resistance | 190 Ohm to 210 Ohm |
| Mounting Thread | 5/8-18 UNF-2A |
| Material | Stainless Steel Threaded |
| Thread Length | 4.0 in. |
| Termination | MS3106 Connector |
| Test Condition Specifications | 276 Hz, 8 pitch Gear, 0.016 Gap., And 270 Ohm Load |