Phase loss protection

[JustCallBen]

I have a client car wash that has a 277/480 Wye service. They have experienced significant equipment losses over the past 6 years due to brownouts, phase losses and the like. There may have been surges but there is no hard data to back that up. Of course, the utility claims no blame or knowledge every time.

The most recent incident was a phase loss due to a defective fuse at the transformer on the pole. I was there when the lineman changed it out and I gave the old fuse to the customer for evidence. The lost phase then caused burn out of the coils of 8 contactors probably due to faulty voltage from the in-house 120/240 transformers. One motor was lost but not sure if it was due to the phase loss as it was pretty crusty to begin with.

Anywho, I would like to provide phase loss protection for the main service and for a 100A MCC downstream from that. What equipment would you recommend?

I've looked at shunt trip but it seems like most of them are not really focused on my application as they require an energized circuit to shunt. What if the phase that I need to shunt is the one that is lost?

 

[hillbilly1]

They do have them with a capacitor back up, don’t ask how I know! Found out when hooking up the wiring with the utility disconnected. LOL!

 

[hillbilly1]

Here’s a thread about it a while back.

Shunt Trip

When is a shunt trip required on the outside of a building? When is a shunt trip required on the outside of a building? You're going to have to make your inquiry a bit more clear. Knowing that a shut trip is usually a breaker option are you also implying that the breaker is located outside the...

forums.mikeholt.com

 

[ptonsparky]

Little Fuse has phase loss monitors. Others do as well. Monitor power factor on a couple of the main motors. Use control logic to shut down every thing or individual loads. Could be worked into a shunt trip breaker. All sorts scenarios.

 

[hillbilly1]

Just had a phase loss this morning, at a plant I do a lot of work for, third time in the past year and a half. Once was a bad fuse at the pole, the other two, poco lost part of the grid for a couple of square miles. Second time, lost 8 led highbays. This time, a large laminator quit talking to the PLC, and they are having to call Italy in the morning to try and get it back on line. They have a large glass tempering oven, but it has 500 kva UPS backing it up. Now they want a 200 kva UPS to back up the laminate oven. At least I have them trained to shut down the six air compressors they have when they lose a phase. The rest of the machines except the punches have built in phase loss protection.

 

[JustCallBen]

My research has shown me a phase loss indicating (protection) device which could ride parallel with the shunt trip. When it detects phase loss it would then trip the CTD. Does that sound right?