17405 Simpson, 17405 Datasheet - Page 64

• Manufacturer Part Number: 17405
• Description: Current Meter
• Manufacturer: Simpson
• Type: Ammeterr

Specifications of 17405

• Meter Function: DC Ammeter
• Meter Range: 0A To 10A
• Meter Size/dimensions: 2.5 X 2.5 In.
• Scale Length: 52.7mm
• Meter Shape: Square
• Display Accuracy ±: 2%
• Current Meter Range: 0-10 A
• Accuracy: +/-2 %
• Barrel Size: 2.22"
• Application: Industrial or commercial applications
• Connection Type: Stud
• Diameter, Body: 2.16 in. (ID), 2.22 in. (OD)
• Diameter, Mounting Hole: 0.140 in.
• Dimensions: 2.38"L×2.34"H
• Display Type: Analog
• Function: Ammeter
• Material, Casing: Plastic
• Measuring Range: 0 to 10 A
• Primary Type: Electromechanical
• Range, Measurement: 0 to 10 ADC
• Repeatability: 2%
• Size: 2-1⁄2 in.
• Size, Thread: 1⁄4-28
• Standards: UL Recognized
• Temperature, Operating: -20 to +65 °C
• Equipment Type: DC Current Meter
• Range: 0 - 10
• Lead Free Status / RoHS Status: na
• Lead Free Status / RoHS Status: na

C
6
Formula:
Where:
The ratio of the current transformer can be modified by adding
more primary turns to the transformer. By adding primary
turns, the current required to maintain five amps on the sec-
ondary is reduced.
Example:
1 Primary Turn
2 Primary Turns
4 Primary Turns
Donut Current Transformer Wrapping Information
Donut Current Transformer Wrapping Information
Nameplate
Nameplate
Nameplate
Primary Turn Ratio Modification
100:5
100:5
100:5
Ratio
Ratio
Ratio
A 100:5 current transformer designed for one
primary turn.
Ka = Kn x Nn / Na
Ka = Actual Transformer Ratio
Kn = Nameplate Transformer Ratio
Na = Actual Number of Primary Turns
Nn = Nameplate Number of Primary Turns
Actual
Actual
Actual
Ratio
100:5
Ratio
Ratio
50:5
25:5
Formula:
Where:
Example:
(In practicality one turn is dropped from the secondary as a ratio correc-
tion factor.)
The ratio of the current transformer can be modified by altering the
number of secondary turns by forward or backwinding the secondary
lead through the window of the current transformer. By adding second-
ary turns, the same primary current will result in a decrease in second-
ary output. By subtracting turns, the same primary current will result in
greater secondary output.
Again using the 300:5 example adding five secondary turns will require
325 amps on the primary to maintain the 5 amp secondary output or
Deducting 5 secondary turns will only require 275 amps on the primary
to maintain the 5 amp secondary output or
The above ratio modifications are achieved in the following manner:
Primary Turn Ratio Modification
lp
ls
lp - Primary Current
ls - Secondary Current
Np - Number of Primary Turns
Ns - Number of Secondary Turns
A 300:5 Current Transformer.
300p
325p
325p
5s
5s
5s
Ns
Np
60s
1p
65s
1p
65s
1p