What to do if Minster SCRB-68 unit runs only at full drive motor speed?
- DDestiny Lloyd DDSAug 3, 2025
If your Minster Industrial Electrical unit runs only at full drive motor speed, first ensure the issue is electrical by checking the coupling excitation on terminals 5 (F1/C1 signal) and 3 (F2/C2 signal). Also, verify the D.C. voltage between terminals 9 (R signal) (+) and 7 (G1 signal) (-) is zero when the speed potentiometer is turned down. Check for tachometer feedback voltage, A.C., between terminals 7 (G1 signal) and 12 (G2 signal). If the drive continues to run after turning the power switch off, the drive has likely failed due to a locked center bearing or a closed air gap in the coupling.