S   LUTIONS

Welcome to   S    LUTIONS, a monthly newsletter provided by Jacco & Associates. Jacco’s focus on system knowledge provides you with the engineering support and product solutions for your applications.

 61 Milford Dr.  Hudson, OH  44236  Phone:(330) 463-0100  Fax:(330) 463-0101

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Questions or comments? E-mail us at opportunity@jacco.com

Question:    In order to air balance a direct drive fan, which of the following can be used?

                   A.) EC Motor     B.) VFD     C.) Banding     D.) A, B & C

Prize:        Apple TV!

Respond by January 16^th with the correct answer to be entered in the raffle for this month’s prize!

Question:  To promote cabinet longevity, Aaon has incorporated which of the following construction standards?

                  

Answer:    D.) All Of The Above.  Congratulations to James Dudt for winning an LCD HDTV!

Belt Drive Pitfalls

Aaon provides Direct Drive fan systems on all of their HVAC systems in lieu of belt driven systems.  Some people may ask why and this newsletter will help explain the benefits of direct drive systems over belt driven systems.

 

Power Loss: Direct drive systems transfer power directly from the motor to the fan.  Belt driven systems transfer power through a belt and pulley system.   This transfer is not 100% efficient and can result in up to 15% power loss as outlined by AMCA 203-90 (see Figure 1).  This inefficiency is a result of mis-alignment and belt slippage.

 

Belt Maintenance: Belt driven systems need to be routinely inspected and serviced to insure proper alignment and inspect or change belts due to wear or stretching.

 

Bearing Maintenance: Belt driven systems have an additional set of bearings as opposed to direct drive systems (see Figures 6&7).  The tension on the belt from the motor to the impeller shaft can be as much as 15 times greater than in a direct drive system.  The belt must maintain enough tension in order to insure the belt does not slip.

 

Indoor Air Quality: As belts begin to wear the belt dust is transferred into the air stream which will travel into the occupied space.

 

Noise: Belt driven systems have increased vibration and belt slippage due to the nature of the design.  Both of these         components results into additional noise that is transferred into the building.