I have a building that whenever the chiller starts the lights blink, commputers without ups drop, and phones are sometimes lost. This occures only for a fraction of a second on start than all is ok. We placed a recorder on the main and the only thing of interest is the system voltage runs about 4 volts lower during the complete run time. We also did infered testing and everything looked ok. The trans. is a 500kva with paralled 350mcm al. 40 feet to meter, than 3 300mcm copper per phase to 800amp MDP about 10 feet. The building runs about 150amps without chiller than about 270amps with chiller running. Everything checks out ok, the only problem is for a fraction of second lights dim and a slight hum/vibration of main wires to MDP. thanks, john
blinking lights
- Thread starter jociha
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charlie tuna
Senior Member
- Location
- Florida
Re: blinking lights
how good is the recorder you used? you will need a data logger with the capability of reviewing each cycle. this will show the instantanious amount of voltage drop to the computer power supply during the four or five seconds during the chiller start. infrared the normal path of power between the service and the computer equipment looking for a poor connection that is additive to the normal voltage drop caused by the chiller startup. make sure this test is conducted during maximum current flow operating periods. we use a metrosonics data logger that monitors the power conditions 32 times per cycle. sometimes it's the power company's problem - but you need a good certified meter to prove it!
how good is the recorder you used? you will need a data logger with the capability of reviewing each cycle. this will show the instantanious amount of voltage drop to the computer power supply during the four or five seconds during the chiller start. infrared the normal path of power between the service and the computer equipment looking for a poor connection that is additive to the normal voltage drop caused by the chiller startup. make sure this test is conducted during maximum current flow operating periods. we use a metrosonics data logger that monitors the power conditions 32 times per cycle. sometimes it's the power company's problem - but you need a good certified meter to prove it!
Re: blinking lights
If your are having that much trouble your voltage recorder did not pickup the drop when the chiller starts. From your info the FLA of the chillier is
270 amps - 150 amps = 120 amps. Starting current is about 6 times the FLA or 6 x 120 = 720 amps.
Most of the drop will be in the transformer. Look on the nameplate and get the %Z or %X. The voltage drop will be 720 amps x %Z. Assume the %Z is 4 %. VD = .04 x 720 = 29 volts. This does not include the VD in the service conductors. What is the service voltage? What is the primary voltage?
If your are having that much trouble your voltage recorder did not pickup the drop when the chiller starts. From your info the FLA of the chillier is
270 amps - 150 amps = 120 amps. Starting current is about 6 times the FLA or 6 x 120 = 720 amps.
Most of the drop will be in the transformer. Look on the nameplate and get the %Z or %X. The voltage drop will be 720 amps x %Z. Assume the %Z is 4 %. VD = .04 x 720 = 29 volts. This does not include the VD in the service conductors. What is the service voltage? What is the primary voltage?
Re: blinking lights
Bob makes a good point. It sounds like your recorder is not fast enough to record the dip. In all likely hood there is no real problem other than a design issue, which was overlooked. Voltage drop is going to happen with large loads starting
IMHO if the computers and phone systems did not get put on a UPS then they are not important to the company operation, interuptions and outages should be expected on a daily basis.
Bob makes a good point. It sounds like your recorder is not fast enough to record the dip. In all likely hood there is no real problem other than a design issue, which was overlooked. Voltage drop is going to happen with large loads starting
IMHO if the computers and phone systems did not get put on a UPS then they are not important to the company operation, interuptions and outages should be expected on a daily basis.
Re: blinking lights
The recorder records once every second,we did the infered with every thing running,the voltage is 480 3phase, your right, every second is probably to slow, the problem is only there for a fraction of a second.this problem is like if you were ever in someones house and they turn something big on and the lights dim for a fraction of a second.
The recorder records once every second,we did the infered with every thing running,the voltage is 480 3phase, your right, every second is probably to slow, the problem is only there for a fraction of a second.this problem is like if you were ever in someones house and they turn something big on and the lights dim for a fraction of a second.
brian john
Senior Member
- Location
- Leesburg, VA
Re: blinking lights
Joc:
Your voltage drop may not be an issue at the main, check at the distribution panels. Check at selected loads. Does this happen all the time or at selected times througgh out the day?
What type of recorder are you utilizing?
Joc:
Your voltage drop may not be an issue at the main, check at the distribution panels. Check at selected loads. Does this happen all the time or at selected times througgh out the day?
What type of recorder are you utilizing?
Re: blinking lights
I gather it has been there for a while but the old chiller started once, early each morning and stayed on all day , our new chiller cycles a few times each day, our recorder is a amprobe measuring once every second and this happens every time a commpressor starts thru out the day.
I gather it has been there for a while but the old chiller started once, early each morning and stayed on all day , our new chiller cycles a few times each day, our recorder is a amprobe measuring once every second and this happens every time a commpressor starts thru out the day.
jrdsg
Senior Member
- Location
- Vancouver, Canada
Re: blinking lights
derekbc
"IMHO if the computers and phone systems did not get put on a UPS then they are not important to the company operation, interuptions and outages should be expected on a daily basis."
that's rich. if only everyone were so aware...
derekbc
"IMHO if the computers and phone systems did not get put on a UPS then they are not important to the company operation, interuptions and outages should be expected on a daily basis."
that's rich. if only everyone were so aware...
Re: blinking lights
JOCHIA, sorry for being cynical in my last post. As pointed out you PQ meter is not fast enough to catch the dip. From what you describe, it sounds like it could be normal. Hard to tell since I do not know what size transformer, how long the service drop is, etc.
What does suprise me is most computers and phone system can work at fairly low voltages something like 90 volts on a single phase system.
If you can give some specific details, we can give some specific resolution.
Have a good day. Dereck
JOCHIA, sorry for being cynical in my last post. As pointed out you PQ meter is not fast enough to catch the dip. From what you describe, it sounds like it could be normal. Hard to tell since I do not know what size transformer, how long the service drop is, etc.
What does suprise me is most computers and phone system can work at fairly low voltages something like 90 volts on a single phase system.
If you can give some specific details, we can give some specific resolution.
Have a good day. Dereck
brian john
Senior Member
- Location
- Leesburg, VA
Re: blinking lights
What I would do is rent a high speed recorder with CT's.
Start at the service and work out, monitoring at selected points. The period of time for the monitoring would be based upon captured data, noting of the blinking lights and any other voltage anomilies.
I always tell our customers if the data on your pc is important, get a UPS
An IR scan would also help in determining if there are any high resistacnce connections, that may be contributing to the voltage drop issue. Often the high resistance connections are visible to the naked eye, but one seldom does as through a visual investigation as a IR thermographer will.
What I would do is rent a high speed recorder with CT's.
Start at the service and work out, monitoring at selected points. The period of time for the monitoring would be based upon captured data, noting of the blinking lights and any other voltage anomilies.
I always tell our customers if the data on your pc is important, get a UPS
An IR scan would also help in determining if there are any high resistacnce connections, that may be contributing to the voltage drop issue. Often the high resistance connections are visible to the naked eye, but one seldom does as through a visual investigation as a IR thermographer will.
brian john
Senior Member
- Location
- Leesburg, VA
Re: blinking lights
If you are in an area when the expertise is available, it may be cheaper to sub this out. The learning curve for some recorders may take some time and it is possible you might miss something. Same goes for IR cameras.
RPM, BMI or Dranetz make good recorders (BMI is now Dranetz). Rentals are typically $980.00 to $1680.00 per month, shipping is extra, and the time of shipping is included as part of the rental period. IR cameras are more expensive to rent.
If you are in an area when the expertise is available, it may be cheaper to sub this out. The learning curve for some recorders may take some time and it is possible you might miss something. Same goes for IR cameras.
RPM, BMI or Dranetz make good recorders (BMI is now Dranetz). Rentals are typically $980.00 to $1680.00 per month, shipping is extra, and the time of shipping is included as part of the rental period. IR cameras are more expensive to rent.
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