CHAPTER 4: PROGRAMMING
EPM 5100 ELECTRONIC POWER METER – USER GUIDE
4–15
To use this equation, insert the known quantities from the present installation and the
constant,
K
h
, from the table below, then solve for
K
e
to program the EPM 5100. An example
follows the table.
4.6.3
Upgrade Calculation Example
For example, a customer has a 480/277 V system (3 phase, 4-wire) with a 1600 A main. The
watthour meter with pulse initiation is being replaced with a EPM 5100. The watthour
meter was set for one pulse every ¼-disk revolution. The value to be programmed into the
meter is calculated as follows:
(EQ 4.2)
Therefore, 0.6912 kWh or 6912 watthours should be programmed into the EPM 5100.
Table 4–3: Values of
K
h
for Pulse Initiation
Voltage
System
K
h
69 V
4Y
1.08
120 V
3
4Y
1.2
1.8
240 V
3
4Y
2.4
3.6
277 V
4Y
3.6
480 V
3
4.8
600 V
3
6.0
Disk revolution per pulse
1000
K
e
PT ratio
(
)
CT ratio
(
)
K
h
-------------------------------------------------------
=
1 4
⁄
1
----------
1000
K
e
280 120
⁄
(
)
1600 5
⁄
(
)
3.6
×
------------------------------------------------------------------
=
⇒
1
4
---
1000
K
e
2764.8
------------------
=
⇒
1000
K
e
691.2
=
⇒
K
e
0.6912 kWh
=
⇒
