Customer Has Been Dropping a Phase

[swish41]

Hi all!

One of our customers has been dropping a phase on a three phase system and the other interns and I have been told to simply multiply our data for our other phases by 0.5. I am confused on where this is coming from and why this would work.

Thank you!

 

[ptonsparky]

Hi all!

One of our customers has been dropping a phase on a three phase system and the other interns and I have been told to simply multiply our data for our other phases by 0.5. I am confused on where this is coming from and why this would work.

Thank you!

Data for what?

 

[gar]

190613-1311 EDT

swish41:

Your question as presented is un-understandable.

What does "dropping a phase" mean? Apparently it does not mean loss of a phase, like a fuse blown on one leg.

What are you measuring?

Provide a complete description of your problem.

Note: on a 3 wire three phase system you can measure total power consumption with 2 wattmeters appropriately connected.

.

 

[swish41]

RE

RE

Hello!

We are measuring the KW on each phase.

So we receive data from meters that has 3 phases. Each phase has a KW value assigned to it. Our customer has been loosing the data for one of the phases and they just tell us to multiply a different phases by 1.5 to get back t the phase that was lost.

 

[swish41]

Data for what?

The data is the KW off of each phase.

 

[hbiss]

In this trade the term "dropping a phase" means the loss of one phase of a 3 phase service or supply. It could also mean the loss of one leg of a single phase 120/240v service.

This is vastly different than estimating the missing data of one phase from the other two phases.

-Hal

 

[kwired]

Hello!

We are measuring the KW on each phase.

So we receive data from meters that has 3 phases. Each phase has a KW value assigned to it. Our customer has been loosing the data for one of the phases and they just tell us to multiply a different phases by 1.5 to get back t the phase that was lost.

So are you having actual power loss on one phase or just losing recording information for some reason on that one phase? Sounds like the latter is what you likely are having, but just trying to clarify.

 

[PaulMmn]

It's just a phase they're going through.... :roll:

 

[mivey]

Hi all!

One of our customers has been dropping a phase on a three phase system and the other interns and I have been told to simply multiply our data for our other phases by 0.5. I am confused on where this is coming from and why this would work.

Thank you!

It would have to be empirical data as there is no sound mathematical support for doing that given normal 3-phase unbalanced load.

If the load is well balanced, then adding 1/2 of phase A and 1/2 of phase B to get phase C would be a reasonable assumption. A lot of assuming going on though about load and power factors and would be limited in use.

 

[ggunn]

It would have to be empirical data as there is no sound mathematical support for doing that given normal 3-phase unbalanced load.

If the load is well balanced, then adding 1/2 of phase A and 1/2 of phase B to get phase C would be a reasonable assumption. A lot of assuming going on though about load and power factors and would be limited in use.

If it's balanced, wouldn't the power on phase C be the same as either A or B?

 

[mivey]

If it's balanced, wouldn't the power on phase C be the same as either A or B?

Yes. They may have a slight imbalance and want a better guess. I'm not a big fan of guessing without knowing the use for the result. Precision may or may not be important (quoted from Captain Obvious).

 

[ggunn]

Yes. They may have a slight imbalance and want a better guess. I'm not a big fan of guessing without knowing the use for the result. Precision may or may not be important (quoted from Captain Obvious).

It just seemed to me that if there were enough difference between the average between the power on A and the power on B for it to be significantly different from either that on A or B alone, the power on C could be just about anything.

 

[mivey]

It just seemed to me that if there were enough difference between the average between the power on A and the power on B for it to be significantly different from either that on A or B alone, the power on C could be just about anything.

Yup.