GE 239 Instruction Manual

Also see for 239: Instruction manual

4-10239 Motor Protection RelayGE Multilin4 PROGRAMMING 4 PROGRAMMING4a) CT INPUTSAt 3+$6(&735,0$5$, the 239 shifts the 02725)8///2$'&855(17 settings by afactor of 10 to remove the extra decimal place (see Figure 4–3: SETPOINTS PAGE 2– SYSTEM SETUP above). If changing the 3+$6( &7 35,0$5< setting causes it tocross the 50 A value, the 02725)8///2$'&855(17 is reset to 0 A, forcing the opera-tor to restore the correct value. In previous firmware versions, crossing the 50 Avalue by changing the 3+$6(&735,0$5< setting changed the 02725)8///2$'&855(17setting by a factor of 10 automatically, often without the operator’s knowledge.• PHASE CT PRIMARY: Enter the primary current rating of the phase current transformers. Allthree phase CTs must be of the same rating. For example if 500:5 CTs are used, the phase CTprimary value entered should be 500. When the relay is shipped with factory defaults loaded, thephase CT ratio is set off. When off is the CT value, the 239 is forced to a trip state as a safety pre-caution until a valid CT value is entered. Ensure that the CT is connected to the correct 1 A or 5A terminals to match the CT secondary.• GROUND SENSING: Ground sensing on solid or low resistance grounded systems is possiblewith residually connected phase CTs as shown in Figure 2–3: TYPICAL WIRING DIAGRAM onpage 2–4. If this connection is used enter residual. The ground CT primary will automatically bethe same as the phase CTs. For more sensitive ground current detection a separate core bal-ance (zero sequence) CT which encircles all three phase conductors can be used. In this caseselect core balance 50:0.025. A GE Multilin 50:0.025 CT is available. If a conventional 5 A sec-ondary CT is used to encircle the 3 phase conductors, enter core balance x:5. It is then neces-sary to specify the CT primary using the next message *5281'&735,0$5<.• GROUND CT PRIMARY: This message will only be visible if the ground sensing in the previousmessage is selected as core balance x:5. Enter the CT primary current. For example, if a 50:5CT is installed for ground sensing enter 50. One amp CTs can also be used for ground sensing.In this case enter the CT primary value multiplied by 5. For example, if a 100:1 ground CT isinstalled and the ground sensing is selected as core balance x:5 enter 500 for the primary value.• NOMINAL FREQUENCY: Enter the nominal system frequency as either 50 or 60 Hz. The 239uses this information in the detection of Phase Short Circuit and Ground Fault Trips.b) MOTOR DATA• MOTOR FULL LOAD CURRENT (FLC): Enter the full load amps from the motor nameplate.This is the maximum rated current at which the motor can operate without overheating. It is the1.0× pickup point on the timed overcurrent characteristic. When the current exceeds this value,the timed overcurrent feature begins to time, eventually leading to a trip. Immediate overloadwarning and undercurrent setpoints are multiples of this value. Timed overcurrent is not activeduring motor starting.• OVERLOAD PICKUP INHIBIT: Enter the overload pickup (service factor) specified on the motornameplate if shown. Otherwise enter an overload pickup of 1.00. The pickup inhibit will operateduring start and/or run depending upon the value programmed in the setpoint 86( 29(5/2$'3,&.83 ,1+,%,7 21 described below. During a running condition this value adjusts the pickup atwhich the overload curves begin timing. If the overload pickup is 1.15 for example, the overloadcurves will not begin to operate until the phase current reaches 1.15 × FLC. During a start, 6$)(67$// 7,0( and /2&.(' 52725 &855(17 setpoints will not be used until the current reaches theoverload pickup inhibit setting.This setpoint acts as a lower cutoff for the overload pickup. The trip times are not shifted, but justcut-off below the value specified by the overload pickup inhibit setting.NOTE