Schweitzer Engineering Laboratories SEL-701-1, Instruction Manual

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SEL-701-1 Monitor
Date Code 20011009
Settings Calculation
General Data
3.4
General Data
Identifier Settings
All models of the SEL-701-1 Monitor have the following identifier settings:
The SEL-701-1 Monitor prints the Relay and Terminal Identifier strings at the top
of responses to serial port commands to identify messages from individual monitors.
Enter up to 20 characters, include capital letters A–Z, numbers 0–9, periods (.), dashes
(-), and spaces. Suggested identifiers include the location, process, circuit, size, or
equipment number of the protected motor.
Current Transformer (CT) Configuration Settings
The CT ratio and secondary rating settings configure the monitor to accurately
scale measured values and report the primary quantities. Calculate the phase and
neutral CT ratios by dividing the primary rating by the secondary rating.
EXAMPLE 3.1 Phase CT Ratio Setting Calculation
Consider an application where the phase CT ratios are 600:5.
Set CTR = 600/5 = 120.
Set ITAP = 5 A.
Select phase current transformers for your application so that the primary current
rating is equal to or greater than the motor full load current. Full load current should
not be less than half the CT primary current rating. See
Example 3.1.
Table 3.1 Identifier Settings
Setting Prompt Setting Range Setting Name = Factory Default
Relay Identifier 20 Characters RID = SEL-701-1
Terminal Identifier 20 Characters TID = MONITOR
Table 3.2 CT Configuration Settings
Setting Prompt Setting Range
Setting Name =
Factory Default
Phase (IA, IB, IC) CT Ratio 1–6000 to 1 CTR = 100
Phase CT Secondary Rating 1, 5 A ITAP = 5
Neutral (IN) CT Ratio 1–6000 to 1 CTRN = 100
Neutral CT Secondary Rating 1, 5 A INTAP = 5