Voltage Monitoring 3 Phase Undervoltage Relay Screw Fixing Mounting 50/60 Hz

Voltage Monitoring 3 Phase Undervoltage Relay Screw Fixing Mounting 50/60 Hz

Why need the 4-20mA analog output

The 0-5V standard signal is not suitable for remote transmission, and does not meet the needs of 1-5V, 4-20mA input meters. This requires conversion, and the transmitter is one of the options for conversion. Transmitter becomes the middle bridge of signal conversion, electric protector can choose 4-20MA analog output, can make the signal transmission of protector more sensitive, thus improve the accuracy of protection

♦ Features
Integrative structure or Separate structure, Built-in LED and keypad afford a precise,digital setting, Three-phase monitoring of short-circuit, locked-rotor,overcurrent, undervurrent, phase loss, phase unbalance,overvoltage,undervoltage, Earth fault (should couple with ZCT) ,Fault recording ,RS-485 communication port (optional) , 4-20 mA analog output (optional) unbalance,overvoltage,undervoltage , 2 C/O output contacts, one for trip,one for alert

♦ Protective Functions Typical Applications
-- Short-circuit Pumps
-- Locked-rotor Fans
-- Overcurrent Blowers
-- Undercurrent Motors
-- Phase loss Compressors
-- Phase unbalance
-- Overvoltage
-- Undervoltage
-- Ground fault

The reason maybe makes motor protector broken

In practical applications, there are many reasons that can cause the motor to burn down. It can be divided into the following categories:
(1) Motor overload caused by various reasons, the current is too large;
(2) Current imbalance caused by too low or high voltage, unbalanced phase, or lack of phase (including phase failure due to contactor failure);
(3) The return air pressure caused by refrigerant leakage or pipeline problems is too low, and the motor cooling is insufficient;
(4) damage to the winding insulation or high water content of the refrigerant, short circuit burned, etc. Theoretically, the overload protector can effectively cope with the first two conditions, while the thermal protector can cope with the first three conditions. The “short circuit” in the fourth case may be related to the quality or installation, or it may be related to the high water content of the metal chips or the refrigerant. In actual use, several situations may occur at the same time, and each other is a cause and effect. It may not be possible to use a brand-new compressor as a laboratory, and the problems are often simplified. The biggest limitations of currently used thermal protectors and overload protectors are that they cannot prevent all of the above-mentioned phenomena from happening. Therefore, the protection of the motor can only stay in the “cooling therapy” afterwards, that is, temporarily stopping the compressor. Cool naturally and then operate again. Thermal protectors and overload protectors do not have a limited number of pull-in times, and the motor is often burned in the "protection - operation - reprotect - rerun" cycle. For emergencies, such as winding insulation damage or short circuit caused by copper shavings, etc., the motor will be instantly burned at high temperature, and the thermal protector and overload protector will not react and cannot be protected.

♦ Technical data