Low voltage protection

 
Low voltage measurement and control device is mainly used for the measurement and control of 0.4KV voltage grade of low voltage wire feeding cabinet, outlet cabinet, capacitor cabinet ,there are existing 951D low voltage transmission line protection measurement and control device、926 low voltage outlet protection measurement and control device、953D low voltage motor protection measurement and control device,956D low-voltage capacitor protection measurement and control device, 959 low voltage bus protection measurement and control device、Measurement and control device for 962D low voltage equipment、988D low voltage generator backup protection measurement and control device, such as the improvement of low voltage protection device product line；Products with quick break, time limit quick break, over current, over-current counter time limit, over load, low voltage, over voltage, mother prepared to vote, the incoming line standby power auto switching, compound voltage lockout over current, Pt breaking and perfect protection function, the product is suitable for in power plant, substation, industrial control system, all kinds of low voltage power distribution system, the company with its own advantages in quality, price advantage, service advantage of rapid development, now Yunnan and parts of Northeast China has considerable influence.

Low voltage motor protection relay is a series of protective devices developed for the fault when the low voltage motor is used, set the protection device with protection, measurement, control and communication in one.the protection device collects three-phase current, three-phase voltage, and calculate F, P, Q, COS, Se, Eq and other data,When the protection meet the action condition ,the output of the driving relay is driven to achieve the purpose of protecting the low voltage motor.
description of protective relay protection for low voltage motor
     major function  ：Start timeout, overload, broken phase, grounding, plugging turn protection, current imbalance, short circuit, under load, temperature, under voltage, over voltage, high frequency, low frequency and other related protection functions
 
     protected mode  ：in the process of starting , only start the timeout protection, broken phase protection, current imbalance protection, grounding leakage protection, short-circuit protection, after the completion of the start, the protection of the relevant inputs are put into operation
 
Two,the 926MD starting mode of low voltage motor protection relay
    Direct starting, bidirectional reversible starting, dual-speed motor starting, resistance reduction starting, star / 3D start, auto transformer starting, self-starting, restarting, external shutdown.Note: please indicate the start mode when ordering.
 
 
three． The 926MD main parameters of low voltage motor protection relay：
     working power supply  ：85~265V AC and DC general.
     range of application  ：Suitable for AC 50Hz(60Hz Instructions for ordering)，500kW and below the motor。
     busbar voltage  ：when alternating voltage is Less than 660V，Direct access to the voltage input or through the PT connected to the voltage input 
  
   Communication status：RS-485 communication，ModBus Agreement
     Digital Input /digital output：9  input acquisition,4  relay exit.
      Digital Input  input supply internal power supply（External do add power， otherwise blame by yourself）。
      digital output ：AC250V/5A, DC 30V/5A.
      DC output：1 way 4-20mA can choose output（Normal without the need to order, please note）
      Event record: can record at least 50 event trip record information.
      Installation method: using standard DIN guide rail installation or screw fixed installation in two ways
      Attention: 500kW above the low voltage and low voltage motor protection relay uses: 9431D motor protection control device。
 
four. The 926MD Description of protective relay selection for low  voltage motor：
    when the 926MD rated current of low voltage motor protection relay  is within 200A,use the Low voltage motor protection relay with current transformer ,do not need to match CT: when the rated curent is above 200A,use external current transformer,The  CT two current is 5A,The CT two side 5A current signal is connected to the three-phase current input hole of the protection mutual inductor.CT ratio set in 
the internal low voltage motor protection relay . 
     five．The 926MD Composition and structure of low-voltage motor protection relay    
     The low voltage motor protection relay is composed of three parts.：LCD show ,Controller (connection) and external transformer.
 
six．The 926MD Interference performance of low voltage motor protection relay：
     Can withstand the III standard IEC1000-4-2 level, test voltage 6kV electrostatic discharge test.
     Can withstand the IEC1000-4-3 standard III level, dry meat field strength 10V/m radiated electromagnetic field interference test.
     Can withstand the III standard IEC1000-4-4 and fast transient interference test.
     Can withstand the III standard IEC1000-4-5 level surge test.