Schneider Electric PowerLogic PM5300 Series Specifikace stáhnout pdf (Strana 57)

63230-507-201A1 Power Meter 750

03/2007 Appendix C—Instrument Transformer Wiring: Troubleshooting Guide

Table C– 5: Section III—Case B

Symptoms: 3-Wire Possible Causes

• Phase B current is higher than A and C (except in

System Type 31)

• kVA = about half of the expected magnitude

• kW and kVAR can be positive or negative, less than about

half of the expected magnitude

• PF can be any value, probably a low leading value

• One CT polarity is backwards

Table C– 6: Section III—Case C

Symptoms: 3-Wire Possible Causes

• is higher than and

• kVA = about half of the expected magnitude

• kW and kVAR can be positive or negative, less than about

half of the expected magnitude

• PF can be any value, probably a low leading value

• One PT polarity is backwards

3 V

Table C– 7: Section III—Case D

Symptoms: 3-Wire Possible Causes

• kW = 0 or low, with magnitude less than kVAR

• kVAR = positive or negative with magnitude of close to what

is expected for kW

• kVA = expected magnitude

• PF = near 0 up to about 0.7 lead

• Either the two voltage leads are swapped OR the two current leads are

swapped AND one instrument transformer has backwards polarity

(look for high or phase B current = high)

• The power meter is metering a purely capacitive load (this is unusual); in

this case kW and kVAR will be positive and PF will be near 0 lead

3= 3

Table C– 8: Section III—Case E

Symptoms: 3-Wire Possible Causes

• One phase current reads 0

• kVA = about 1/2 of the expected value

• kW, kVAR, and power factor can be positive or negative of

any value

• The CT on the phase that reads 0 is short-circuited

• Less than 2% current (based on CT ratio) flowing through the CT on the

phase that reads 0

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Schneider Electric PowerLogic PM5300 Series Specifikace Strana 57