HVAC Equipment Causing Surges

M

mikev86

Member
Location
Easton, MD
Occupation
Electrical Designer
Hello all,

We recently had a new 480V panel installed to serve some sensitive automotive equipment and a new 10-ton packaged HVAC unit.

Prior to HVAC unit being installed, SPD counter was at 3. Since HVAC unit was installed we have been getting an average of 4 hits/day.

There are no VFDs present and the HVAC unit is not cycling on and off frequently. We have checked for damaged wires and loose connections, even had Trane come out to investigate their unit and found nothing. That being said, when we turned off the disconnect, the surges stopped.

We are looking at moving the HVAC unit to another panel to not have it on the same source as the sensitive equipment, but have concerns the surges will still happen and the other existing 480V panels do not have any surge protective devices.

Looking for recommendations on what else to check and troubleshoot.

Thank you!
Mike
 
When the surge counter activates is not regulated. It is often a marketing scheme for the SPD vendor to make it seem as though the SPD is working hard and to encourage early replacement.
Put a Power Quality Meter to see if there are real surges being seen and to what magnitude.
 
Jraef said:
Do you now anything about the HVAC equipment? For example, if they are using a Wye-Delta starter on a compressor, that will cause significant spikes on the line when it transitions.
Click to expand...
We didn't open up the HVAC equipment, but did just confirm the surge counter goes up when the compressor kicks on. Voltages all checked out:
278v- A phase to neutral
280v- B phase to neutral
282v- C phase to neutral

278v- A phase to ground
280v- B phase to ground
282v- C phase to ground

484v- A phase to B phase
485v- A phase to C phase
487v- B phase to C phase

Turned down the thermostat so the AC kicked on. SPD light didn't turn red and alarm didn't go off, but counter went up.
 
You must log in or register to reply here.
Top