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Old 07-18-2019, 08:15 AM   #1
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Default Odd readings on meter

We have been installing new meters on property and are running in to a pretty consistent issue. 1 or 2 of the phases on our 3 phase systems will show positive amps, positive voltage and negative power readings. All of these should be coming off of Wye transformers, some of the high voltage may be delta, but the problem transcends both. We have checked ct orientation and the like. We have placed portable meters on the gear to confirm these readings and they read the same. Some of these meters are on restaurant style venues, so not much inductive or capacitive loads. The previous meters did not show these readings, but they were a much older meter that was not bidirectional. We have two types of new meters we are using and both are showing this, so i am thinking these are legitimate readings. Just cant understand why.

I will paste the readings on one that we are dealing with today. Any guidance would be appreciated.
PS sorry for the formatting, i could not paste as a table.

Vab,491.8 V ,491.78,
Vbc,491.8 V ,491.80,
Vca,492.7 V ,492.68,
Van,284.3 V ,284.32,
Vbn,283.3 V ,283.34,
A_Amps,239.6 A ,239.63,
B_Amps,210.2 A ,210.22,
C_Amps,237.1 A ,237.07,
A_Watts,63223.6 W 63223.57,
B_Watts,54996.2 W ,54996.17,
C_Watts,64275.1 W ,64275.06,
A_WattHour,-15241.0 W-hr,,-15241.00,
B_WattHour,27654.0 W-hr ,27654.00,
C_WattHour,-25957.0 W-hr ,-25957.00,
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Old 07-18-2019, 04:56 PM   #2
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How do you get "positive", and "negative" readings on an AC system? Did you read the instructions that came with the equipment?
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Old 07-18-2019, 05:54 PM   #3
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your post shows positive values for all the readings except watthours.

watthours are the stored values of the consumption. if the watthour meters are older, the motors are probably spinning backwards and a phase needs to be swapped (ie. rotation is wrong). I don't know anything about newer electronic meters, but something similar probably applies.
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Old 07-19-2019, 12:27 AM   #4
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Solar, Cogen, capacitors?


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Old 07-19-2019, 11:31 AM   #5
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Several different resteraunt type venues. The most notable one is a food service counter at a cinema.

These are Veris E50's(Schneider EM3500) and a Dent HD 48. All installed according to instructions. Weve been installing them for 5 years with no problem, until someone accidentally order a case of bidirectional units.
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Old 07-19-2019, 11:49 PM   #6
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Does the negative watt-hour reading count up or down with usage?
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