Vibration Monitoring for Air Handler Applications

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Monitoring the vibration of rotating components of enclosed air handling units presents a unique challenge for predictive maintenance programs. The air handling units are expected to maintain consistent environmental conditions, such as flow rate, temperature, and humidity, and often to extremely limited tolerances. In many laboratories, manufacturing, and warehousing spaces, small deviations in operating parameters can result in void products. As a result, opening a unit to access the rotating components to collect vibration data, or even to perform a visual inspection, is impractical because of the potential for ambient air to affect conditions or introduce contaminants.

Common faults with air handling units include:
▶ Unbalance
▶ Misalignment between the sheaves
▶ Looseness
▶ Belt resonance defects / worn belts
▶ Worn or damaged sheaves
▶ Bearing defects
▶ Rubbing
▶ Motor electrical, including rotor bar faults

Vibration Monitoring can be used on Air Handlers to:
▶ Reduce or eliminate exposure to safety hazards
▶ Reduce data collection time while increasing repeatability and data accuracy
▶ Collect data on previously inaccessible fan components
▶ Prevent high-cost failures
▶ Help ensure consistent environmental conditions

The first consideration is whether or not process monitoring or dynamic vibration analysis is right for your condition monitoring program. Due to access concerns, permanent monitoring is the preferred method for repeatability, human safety, and operational effectiveness.

Process monitoring requires 4-20 mA Loop Power Sensors, which will provide the overall vibration level of the machine so that it can be trended and alarmed using the plant DCS, PLC, or SCADA system. Process monitoring will require permanently mounted loop power sensors that output a 4-20 mA signal proportional to velocity or acceleration. Process monitoring will provide an allover understanding of machine health but cannot provide the same level of detailed diagnostic data as dynamic vibration analysis.

Dynamic vibration analysis allows for trended data and machine health diagnostics. However, dynamic vibration sensors can be paired with CTC’s SC300 Series signal conditioners to create a hybrid approach for both process monitoring and dynamic analysis. A signal conditioner converts the signal from dynamic sensor into a 4-20 mA output, so it can be tended and alarmed using the plant DCS, PLC, or SCADA system but also used for more in-depth predictive maintenance.

Regardless of whether or not a signal conditioner is the right choice for your program, CTC has a variety of accelerometers for use in air handler applications.

LOOP POWER SENSOR OFFERINGS FOR AIR HANDLER APPLICATIONS:
4-20 mA monitoring will provide a cost-effective, online process monitoring solution. Our standard LP200 Series and LP300 Series can be permanently mounted for a 4-20mA output proportional to vibration in velocity or acceleration respectively. 


LP202 Loop Power Sensor, 4-20 mA Output Proportional to Vibration in Velocity, Top Exit 2 Pin Connector

LP204 Loop Power Sensor, 4-20 mA Output Proportional to Vibration in Velocity, Side Exit 2 Pin Connector



LP302 Loop Power Sensor, 4-20 mA Output Proportional to Vibration in Acceleration, Top Exit 2 Pin Connector

LP304 Loop Power Sensor, 4-20 mA Output Proportional to Vibration in Acceleration, Side Exit 2 Pin Connector

CTC's Loop Power Sensors can be paired with our PMX enclosures to trigger alarm and shutdown.

RELAY AND PROTECTION EQUIPMENT FOR USE WITH LOOP POWER SENSORS:
CTC'S PMX Series Enclosure is a fiberglass, 1-4 channel process control enclosure with display and relay. These enclosures are designed for loop power sensor input and the relays can trigger alarm or shutdown.


GENERAL PURPOSE ACCELEROMETERS:
General purpose accelerometers typically meet the needs of air handling units. In limited access areas, like near belt guards, side exit connector accelerometers are typically suggested. CTC's Dynamic Vibration IEPE Ultrasound Sensors also provide an excellent solution for general-purpose monitoring with the ability for high-frequency fault detection. Some of our most popular general purpose accelerometers include:

AC102 Standard Size Multipurpose Accelerometer, Top Exit 2 Pin Connector, 100 mV/g, ±10% Sensitivity Tolerance, ±80 g, Dynamic Range

AC104 Standard Size Multipurpose Accelerometer, Side Exit 2 Pin Connector, 100 mV/g, ±10% Sensitivity Tolerance, ±80 g, Dynamic Range

AC292 Premium Compact Accelerometer, Top Exit 2 Pin Connector, 100 mV/g, ±5% Sensitivity Tolerance, ±80 g, Dynamic Range

AC294 Premium Compact Accelerometer, Side Exit 2 Pin Connector, 100 mV/g, ±5% Sensitivity Tolerance, ±80 g, Dynamic Range

 

UEB332 Dynamic Vibration IEPE Ultrasound Sensor, 1/4-28 Mounting, Top Exit 2 Pin Mini-MIL Connector, 100 mV/g, ±10% Sensitivity Tolerance, ±50 g, Peak

UEA332 Dynamic Vibration IEPE Ultrasound Sensor, 1/4-28 Mounting, Side Exit 2 Pin Mini-MIL Connector, 100 mV/g, ±10%, ±50 g, Peak

 

CABLES & CONNECTORS:
Due to the environment within the air handling unit, the cable connecting the accelerometer to the switch box needs to be robust, chemical resistant, moisture resistant, and reliable in a caustic environment, such as CTC's Premium V Series Viton™ Seal-Tight Boots or A Series Standard MIL-Style Connectors.

 

V Series Seal-Tight Viton™ Boot Connectors are our most rugged and durable connectors, featuring an IP69 rating for excellent ingress protection, as well as superior resistance to many chemicals, including chlorine:

V2R Premium, High Temperature 2 Socket MIL-Style Seal-Tight Viton™ Boot Connector with PPS Insert, For Permanent Mounting, 350 °F (177 °C) Maximum Temperature

A Series MIL-Style Connectors are general purpose connectors that work in a variety of environments. The A Series comes with stainless steel locking ring and a variety of material options, including Polycarbonate, PPS, and Nylon.

A2A Polycarbonate Molded, 2 Socket-MIL Style Connector, for Permanent Mounting, 250 °F (121 °C) Maximum Temperature

JUNCTION BOXES:
Junction Boxes can be used for local measurements or the transmission of data to online vibration monitoring systems. Junction Boxes can also be used for cable reduction purposes or for switched outputs during manual route data collection of the vibration signals. Depending on the environment in which your junction box is mounted, CTC offers the majority of our junction boxes in either fiberglass or stainless steel options.