WE MAKE IT EASY.
4CTV Formula:
I
L
(load amps) =
20 V
o
turns 5
x
( )
V
o
= VDC from 4CTV
turns= number of times conductor
passes through 4CTV
APPLICATION #1. Monitoring Loads Under 20A
Note: If I
L
is always below 10A, multiple passes of the conductor will improve
scaling. The sum of these amperages must remain below 20A.
APPLICATION #2. Monitoring Loads Over 20A with a Current Transformer
Note: If the CT is oversized, multiple conductor passes or more
secondary turns through the 4CTV or 4CMA will improve
scaling. The CT output should not exceed 5A or the CT
secondary turns should not total more than 20A.
4CTV Formula:
I
L
(load amps) =
5
x
( )
V
o
= VDC from 4CTV
CT primary
rating
V
o
APPLICATION #3. Monitoring and Summing Multiple Loads
Note: If the loads are from secondaries of current transformers, the CT ratios and the turns on the 4CTVs and
4CMA must all be the same. If CTs are used, the CT primary amps would be the total for all CTs used.
4CTV Formula:
For loads under 20 amps
I
LT
(load amps) =
5 x N
x
( )
V
o
= VDC from 4CTVs
turns = number of times conductor passes
through 4CTV
N = number of loads monitored
20 x N
turns
V
o
4CTV Formula:
For loads over 20 amps
I
LT
(load amps) =
x
( )
CT primary
rating total
V
o
5 x N
Conductor
4CTV
4CTV
LOAD #1
I
L1
LOAD #2
I
L2
LOAD #3
I
L3
4CTV
4CTV
4CTV
Current
Transformer
I
L
0
-
5
A
M
P
S
Conductor
Current
Transformer
4CTV
4 turns for CTs with 5A secondaries
20 turns for CTs with 1A secondaries
Power
Supply
24 VDC ± 10%
I
O
(4-20 mA)
4CMA
Conductor
Load
600
Max
V
o
= (0-5 VDC)
30 k
I
o
= mA from UMM
N= number of loads monitored
4CMA
Formula:
For loads under 20 amps
I
LT
(load amps) =
20 x N I
o
- 4
turns 16
x
( )
I
LT
(load amps) =
I
o
- 4
16
CT Primary
rating total
x
( )
4CMA
Formula:
For loads over 20 amps
turns = number of times conductor passes
through
4CMA
4CMA
Formula:
I
L
(load amps) =
I
o
- 4
16
( )
I
o
= mA DC from 4CMA
CT primary x
rating
I
O
(4-20 mA)
Power
Supply
24 VDC ± 10%
I
L
4CMA
4 turns for CTs with 5A secondaries
20 turns for CTs with 1A secondaries
0
-
5
A
Conductor
Load
600
Max
4CMA Formula:
I
L
(load amps) =
20 I
o
- 4
turns 16
x
( )
I
o
= mA DC from 4CMA
turns= number of times conductor
passes through 4CMA
I
L
I
L
Power
Supply
24 VDC ± 10%
Current
Output
4-20 mA
SIG OUT
COM
24 PWR
IN 1
IN 2
IN 3
UMM
I
LT
= I
L1
+ I
L2
+ I
L3
I
O
Universal
Math
Module
LOAD #1
I
L1
LOAD #2
I
L2
LOAD #3
I
L3
4CMA 4CMA
Minimum
Load
Voltage Output
V
o
= (0-5 VDC)
30 k
Minimum
Load
Voltage Output
V
o
= (0-5N VDC)
30 k
Minimum
Load
Voltage Output
4CMA
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