REFDESDESCRIPTIONDS1, DS2FS1INDICATOR LIGHTFREQUENCY METER, 0-400 HzSWITCHFigure 8-12. Underfrequency Relay Test Set-Up(c) Check capacitor Cl between points 5 and6 on terminal board TB106. Capacitance should be 60uf.(d) Replace components found to be defective.(4b) Test the total resistance of rheostat (R28).Total resistance should be 15,000 ohms + 10%. Testresistance between wiper arm and either–end ofrheostat. Resistance should vary between 0 and15,000 Ohms.(5) Make a point-to-point check of all wiringand chassis mounted components.c. Special Relay Assembly.(1) Check all components for signs of physicaldamage.(2) To test the crank relay (K3), apply 24-28Vdc across the two small terminals and check forcontinuity across the two large terminals.(3) See figure 8-12 and connect the under-frequency relay (Kl2) (Mode II Sets) as shown.Test as follows:ME 6115-545-34/8-12 C1(a) Adjust the frequency to 400 Hz and theinput votage to 120 volts. Relay contacts should“pick up”; lamp DSl should light and DS2 shouldextinguish.(b) Lower frequency slowly until relay con-tacts drop-out (lights transfer). Contacts shoulddrop out at 370 + 5 Hz.(c) Raise frequency slowly until contactspick up. DSl should light and DS2 should extinguish.Contacts should pick up at 370 to 395 Hz.(d) Raise voltage to 132 volts and checkdrop out (lights transfer). Drop out should occurwithin ± 1 cycle of drop out at 120 volts.(4) To test the undervoltage relay (Kll),(Mode XI) connect the relay in a test circuit as illus-trated in figure 8-13, and proceed as follows:(a) Adjust ac power supply to 120 volts,400 Hz. Lamp DSl should extinguish and DS 2should light.(b) Reduce voltage slowly to 104 volts andhold for 2 minutes. Lamp DS1 and DS2 shall main-tain states.8-18 Change 1
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
