Schneider Electric K series Manual do Utilizador descarregar pdf (Página 41)

PLSED309039EN PM1000 Series Power Meters

08/2010 Chapter 5 – Installation

CT Connections

Mount the current transformers (CTs) as close as possible to the power

meter for best accuracy. The following table illustrates the maximum

recommended distances for various CT sizes, assuming the connection is

via 2.5 mm

(14 AWG) cable.

Table: 5-5: CT size and maximum distance

5 A CT size

Maximum Distance in metres (in feet/inch)

(CT to PM1000 power meter)

2.5 VA

3.05 m (10 ft/120 in.)

5.0 VA

4.6 m (15 ft/181 in,)

7.5 VA

9.15 m (30 ft/360 in.)

10.0 VA

12.2 m (40 ft/480 in.)

15.0 VA

18.3 m (60 ft/720 in.)

30.0 VA

36.6 m (120 ft/1441 in.)

 User programmable CT primary range: 1 A to 99 kA AC.

 CT secondary: 1 A or 5 A AC (programmable)

Other values are also programmable to compensate CT errors if desired.

 Power meters CT burden: 0.2 VA maximum per input.

See the ―PROG menu — Setup‖ on page 17 for more information.

NOTE:

The PT primary and secondary values must be user programmed before using the power

meter. Otherwise, the readings will be wrong.

With dual- range CTs; select the best range for programming the power meter. If you change

the range thereafter without re-programming the power meter, the power meter will read

erroneous values.

CT Polarity

When the power meter is connected using the CTs, you must maintain

correct CT polarities. CT polarities are dependent upon correct connections

of CT leads, and upon the direction the CTs are facing when clamped

around conductors. The dot on the CT must face the line side; the

corresponding secondary connection must connect to the appropriate input

on the power meter.

Failure to connect CTs properly results in inaccurate power readings. If your

power meter is not reading power properly, it is more than likely that the CT

is incorrectly wired. If one or two CTs are reversed, then energy parameters

accumulate only one phase value. If two or all the phases of the CT are

reversed, energy will not accumulate. (Energy import will not be measured).

CT Connection Reversal

To check the polarity of the CT after the power meter has been installed,

simply look at the phase-wise W (Watt) readings to see that each of the

readings are positive (assuming you are consuming power). If one of the W

readings is negative, that particular phase CT is reversed and must be

corrected. On the other hand if you are exporting power, all three phase-

wise W readings must be negative.

1 2 ... 36 37 38 39 40 41 42 43 44 45 46 ... 80 81

Comentários a estes Manuais

Sem comentários

Schneider Electric K series Manual do Utilizador Página 41

Comentários a estes Manuais

Manuais e produtos relacionados com Medição, teste e controlo Schneider Electric K series