Industrial control for HVAC systems — Redundant VFDs

What’s up everyone. Josh Kingsley here, your host for All Things Control by Eaton.

In this installment of What’s in the Trailer, we’ll look at an HVAC system for a commercial building like a hospital. This system is outfitted with a redundant drive configuration, HVAC enclosed control and HVAC definite purpose contactors. Let’s explore what’s in the trailer.

Maximum VFD uptime with a redundant system

Assume it's hurricane season. A particularly bad storm is raging one night and lightning strikes Acme General Hospital, causing a power surge in the building. This damages the primary of two PowerXL DH1 HVAC variable frequency drives. Because the two VFDs are constantly communicating with each other about their performance status, the secondary DH1 discovers that the primary is offline and immediately assumes control of the system. This ensures that uptime is maximized by providing an alternative VFD to get the system back up and running in virtually no time.

Faster repairs with a redundant VFD system

Now, what if Acme’s HVAC system suffers a break in the belt that propels the motor? I am going to demonstrate this by touching the belt break demo on the XP 503 HMI. As you can see, the DH1 will detect the loss of load, will turn off the compressor and condenser, and will not allow you to turn on the system until the belt is repaired. 

In addition, because the secondary VFD is communicating with the primary and knows that the fault has been detected because of a broken belt, it will not attempt to assume control of the system. The DH1 will instead communicate the fault to Acme’s maintenance manager so that they can have it fixed. In other words, by signaling the fault real-time, the DH1 has helped ensure that the system can be repaired faster. 

Think about how important these two features are to doctors and nurses providing critical care to patients. Making sure that their facility’s environment is consistently managed can be life-saving.

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