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  1. #1

    Single vfd for 6 fans ach800

    Have an application which has a single vfd controlling 6 fans. Has anyone come across such an application? It's the ach800 series vfd.

  2. #2
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    I haven't run across more than two in a field built system. Fanwalls (Huntair) are a whole nother story.
    UA LU 562

  3. #3
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    Yes. What are you wanting to know?
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
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  4. #4
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    374
    Fan walls, yes.

  5. #5
    My application calls for single acs800 Vfd controlling 6 fans. Each fan has an isolation damper preceeding it. The sequence calls for all fans to be running at the same time to maintain the air flow set point. If one fan fails, the remaining 5 will adjust their speeds to maintain the setpoint. I need to know how to wire the safeties and the damper switches to these drives? Any suggestions?

  6. #6
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    Quote Originally Posted by zerogravity View Post
    My application calls for single acs800 Vfd controlling 6 fans. Each fan has an isolation damper preceeding it. The sequence calls for all fans to be running at the same time to maintain the air flow set point. If one fan fails, the remaining 5 will adjust their speeds to maintain the setpoint. I need to know how to wire the safeties and the damper switches to these drives? Any suggestions?
    VFD should be sized for the sum of the HP of all the motors. Each motor should have it's own motor protection/overload. Why use electronic dampers instead of barometric? In other words barometric would be preferred, then you don't have to mess with added controls nor actuators.

    I'd wire a current sensor switch downstream of the motor overload that enables the damper to open once the current sensor senses enough current. Or you could use aux contacts on the motor overload to switch the actuators on with an interlock to a 'fanwall' call.

    The only safeties I can think of is fire shutdown, high/low static but that is standard stuff that simply shuts down the drive. If you're not familiar how to wire those call in a professional.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    http://threedevilskennel.com/ - not my website.
    Versatile Hunting Dog Federation - www.vhdf.org/


  7. #7
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    Quote Originally Posted by crab master View Post
    VFD should be sized for the sum of the HP of all the motors. Each motor should have it's own motor protection/overload. Why use electronic dampers instead of barometric? In other words barometric would be preferred, then you don't have to mess with added controls nor actuators.

    I'd wire a current sensor switch downstream of the motor overload that enables the damper to open once the current sensor senses enough current. Or you could use aux contacts on the motor overload to switch the actuators on with an interlock to a 'fanwall' call.

    The only safeties I can think of is fire shutdown, high/low static but that is standard stuff that simply shuts down the drive. If you're not familiar how to wire those call in a professional.
    I was recently told to add up the sum of the FLA on all motors, not just the sum of the HP. And I think he is talking about back draft dampers in case a fan motor goes down you down have a path for short circuiting the air. Also, yes, each motor needs to be fused for individual protection. Although he does mention the safeties on the damper so I am kind o lost. Never have seen that.

  8. #8
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    Good point on the HP vs. amperage. The VFD has to be able to handle both sums.
    We don't use fuses/individual circuit breakers to each motor, just motor overloads. Of course the main upstream is protected.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    http://threedevilskennel.com/ - not my website.
    Versatile Hunting Dog Federation - www.vhdf.org/


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