1 HVACR115 – Mechanical for Gas Heat Blower Assemblies
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HVACR115 – Mechanical for Gas Heat
HVACR115 – Mechanical for Gas Heat
Blower AssembliesBlower Assemblies
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Blower AssembliesBlower Assemblies
• Are constructed to pull air through the return air ducts and filter, then push air through the heat exchanger and supply ducts.
• They require careful adjustment to produce enough volume and velocity to maintain comfort at design conditions.
• Are constructed to pull air through the return air ducts and filter, then push air through the heat exchanger and supply ducts.
• They require careful adjustment to produce enough volume and velocity to maintain comfort at design conditions.
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Blower AssembliesBlower Assemblies
• There are two types of blower assemblies available:– Direct Drive– Belt Drive
• There are two types of blower assemblies available:– Direct Drive– Belt Drive
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Direct DriveDirect Drive
• Approximately 1050 RPM on high speed.
• Motor is attached by either the blower wheel hub assembly on the shaft or through a spider coupling.
• Supported by motor shaft.
• Variable speed requires a multi-speed motor.
• Used in residential applications mainly.
• Approximately 1050 RPM on high speed.
• Motor is attached by either the blower wheel hub assembly on the shaft or through a spider coupling.
• Supported by motor shaft.
• Variable speed requires a multi-speed motor.
• Used in residential applications mainly.
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Spider CouplingSpider Coupling
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Belt DriveBelt Drive
• Motor is usually at 1725 RPM.
• Blower wheel is supported by the shaft and bearings.
• Variable speed is obtained by varying the setting of a split pulley.
• More often used on light commercial applications.
• Motor is usually at 1725 RPM.
• Blower wheel is supported by the shaft and bearings.
• Variable speed is obtained by varying the setting of a split pulley.
• More often used on light commercial applications.
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Adjustable PulliesAdjustable Pullies
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Blower AssembliesBlower Assemblies
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Belt Drive BlowersBelt Drive Blowers
• It is important that the drive on the motor and the pulley on the blower wheel be perfectly aligned.
• Any belt wear, more than normal, is most often attributed to the improper alignment of the pulley and motor.
• It is important that the drive on the motor and the pulley on the blower wheel be perfectly aligned.
• Any belt wear, more than normal, is most often attributed to the improper alignment of the pulley and motor.
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ECM and VFD MotorsECM and VFD Motors
• Today more and more manufacturers are using ECM and VFD motors to control air volume.
• Speed of the motor is directly linked to application and volume demand.
• Can compensate for air blockages.
• Today more and more manufacturers are using ECM and VFD motors to control air volume.
• Speed of the motor is directly linked to application and volume demand.
• Can compensate for air blockages.
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VFD MotorsVFD Motors
• VFD – Variable Frequency Drive remember what determines the speed of an electric motor
• Frequency of motor and the number of field poles. Rpm = (fr x 120)/NP
• If you drop the frequency you slow down the motor. i.e. a 1050 rpm motor with 30htz instead of 60htz spins at appr.600 rpms.
• If you drop the speed you drop the volume of air delivered.
• VFD – Variable Frequency Drive remember what determines the speed of an electric motor
• Frequency of motor and the number of field poles. Rpm = (fr x 120)/NP
• If you drop the frequency you slow down the motor. i.e. a 1050 rpm motor with 30htz instead of 60htz spins at appr.600 rpms.
• If you drop the speed you drop the volume of air delivered.
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ECM MotorsECM Motors
• ECM – Electronically Commutated Motors.
• The motors speed is controlled by inverting the voltage from AC to DC and then sent to the motor at the amount needed for whatever speed is needed.
• ECM – Electronically Commutated Motors.
• The motors speed is controlled by inverting the voltage from AC to DC and then sent to the motor at the amount needed for whatever speed is needed.