The GMR-32B MUST be installed on the line (supply) side of a variable frequency drive (VFD) . It monitors the quality of the mains power supply, and installing it on the output side of a VFD will expose it to high-frequency harmonics and distorted waveforms that can cause severe damage to the controller and malfunction.

If you’d like, I can draft a full 8–12 page manual in this format (including diagrams and the experiments with step‑by‑step measurement procedures). Which sections should I expand first?

THREE-PHASE SOURCE (LINE SIDE) │ │ │ ▼ ▼ ▼ ┌───────────────────────┐ │ L1 L2 L3│ <-- Primary Monitoring Inputs │ │ │ GMR-32B │ │ │ │ NO1 COM1 NC1 NO2 │ <-- Auxiliary Control Contacts └───────────────────────┘ │ │ │ │ ▼ ▼ ▼ ▼ To Contactor / Safety Interlock Loop

If you can provide a photo of the unit or the manufacturer listed on the casing, I can help locate the specific manual for that brand.

The relay monitors the voltage polarity; if the sequence is wrong, the internal mechanism opens the contacts to cut power. Typical Applications HVAC: Central air conditioning compressors.

Complete Technical Manual & User Guide for the GMR-32B Phase Controller The GMR-32B Phase Controller

Installation should be performed by a qualified electrician.

: Upon powering up, a green LED usually indicates a correct phase sequence. A red LED often signals a fault, such as phase reversal or loss. Why You Need One

Connect the three incoming phases from your main breaker directly to the input terminals. Wire L1 to Terminal 1, L2 to Terminal 2, and L3 to Terminal 3.

—End of manual—

5 LEDs (Normal, Phase Loss, Reverse Phase, Overvoltage, Undervoltage). Installation & Wiring

The GMR32B Phase Controller can be configured using the user interface, which consists of a display screen and a keypad. The following parameters can be configured:

Lights up if any phase (L1, L2, L3) is missing or if there is a three-phase voltage imbalance.