). If utility work or maintenance inadvertently swaps two lines, the motor will instantly spin in reverse. In machinery like scroll compressors or industrial pumps, reverse rotation can permanently destroy internal mechanical components within seconds. The GMR-32B scans this sequence prior to startup and cuts the control circuit if an error is present. 2. Phase Loss Protection (Single-Phasing)
When the three supply voltages are significantly unbalanced, the motor experiences negative‑sequence currents that produce double‑frequency heating in the windings. The GMR32B will detect severe imbalance (greater than 20% imbalance) and trigger its protection, but while the unit is still powered and the imbalance is below the alarm threshold, the distorted waveform can cause the protection module’s own power supply to run hotter than normal. This is especially true of the GMR‑32B_Smart‑Plus model, which is specifically designed for environments with high‑order harmonics (e.g., inverters, large VFDs) and uses a Buck‑topology power supply to maintain stable operation in such contaminated networks. gmr32b phase controller manual hot
The front interface features localized LED indicators designed to reveal real-time fault codes and line behavior: LED Label / State Condition Identified Internal Relay Action All phases balanced, proper phase sequence Relay energizes (NO contacts close, system operational) Phase Reverse (ON) Phase sequence of lines is incorrect Instantly trips / Prevents equipment startup Phase Loss (ON) Static or dynamic loss of any phase ( Trips control contact loop to prevent single-phasing motors Over/Under Volt (ON) The GMR-32B scans this sequence prior to startup