KR-939SB4 Integrated Four-Parameter Composite Probe

This probe integrates four two-wire transmitters, outputting four channels of standard 4–20 mA current signals. It can interface with the Kere Company "KR-939B4 Fan Safety Monitor" or directly connect to computer data acquisition and control systems (e.g., DCS, PLC)..

As is well known, cooling tower fans are important equipment for production enterprises. In long-term and harsh operating environments, it is inevitable to produce component corrosion, oil deficiency wear, material fatigue, which can cause other components to loosen, friction to intensify, dynamic imbalance, and increased vibration. If not detected and treated in a timely manner, it will cause serious accidents such as bearing burnout, mechanical damage, and even blade fracture.

Numerous statistical practices have proven that the most critical safety operating indicator for cooling tower fans is mechanical vibration parameters.According to ‘the International Organization for Standardization ISO-2372 standard’ for safety monitoring of this type of equipment, the complex vibration monitoring quantity generated by the moving friction components of each part of the fan should be the true effective value (RMS) of the vibration velocity proportional to the vibration energy;The frequency band range of vibration detection should meet 10-1000Hz;The detection of vibration direction should be all-round.This requires monitoring instruments to have high quality performance.

The KR-939SB4 probe can conveniently measure the True RMS (defined as severity value in equipment safety standards) of vibration velocity across full 360° coverage and wide frequency ranges for vibrating objects. Simultaneously, it monitors temperature changes at vibration points, making it suitable for direct measurement of vibration safety and temperature rise safety in various large and medium-sized rotating machinery and moving equipment (e.g., blowers, water pumps, gearboxes, bearing housings, rolling friction components). This eliminates the need for additional signal conversion or calibration processes

Main technical performance and indicators

Measurement range of lubricating oil temperature:0～100 ℃ ，

Compreh-ensive error of temperature measurement:±1℃

Oil level measurement characteristics:

Measurement range of lube oil level:0～50㎜（10 mm for the gear box under normal oil level oil limit position）, 

Maximum error of oil level measurement： <= ±1㎜

Ambient temperature from -40 to 65 C（Extreme temperature resistance from -50 to 150 C）

Vibration measurement characteristics:

Range of vibration measurement:0～20 ㎜/s ，The measurement output is proportional to the effective value of the vibration velocity (RMS). Frequency range of vibration measurement: 10～1000HZ, Maximum error of vibration measurement: <=±1㎜/s

Signal output characteristics:

Active current type output:DC/4～20mA ，Requirements for passive resistive load

Maximum load resistance:< 300 Ohm

Supply characteristics of power supply:

Working voltage：DC/24V±4V，

Maximum protection voltage:DC/30V ，

Rated current：DC/80mA, 

Maximum instantaneous working current:120mA，

Internal voltage Ambient temperature range:－20～80℃，

Ambient humidity range：0～100％（The port is sealed with 704 silicone rubber seals）

Electrical connections:

Environmental temperature range: -20 to 80°C,

Environmental humidity range: 0 to 100% (ports sealed with 704 silicone rubber).

Electrical connection:

The probe uses a 5-wire, 6-terminal configuration:  

1# +V: +24 V power supply;

2# GND: Connected to the probe housing (shielding optional)

3# T: Temperature signal output; 

4# Z: Vibration signal output (X-axis); 

5# Y: Vibration signal output (Y-axis);

6# X: Vibration signal output (Z-axis).

Typical wiring see [Fig. 2] Schematic diagram of probe wiring principle.

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