Summary

The MNS type low-voltage drawer switchgear (hereafter referred to as the switchgear) is developed by our company, drawing on and improving upon the MNS series of low-voltage switchgear from ABB. It represents one of the most advanced low-voltage drawer switchgear systems in China today. The product consists of standardized, modular units, and the drawers are equipped with a reliable mechanical interlock mechanism, enhancing user safety and reliability during operation.

This switchgear is designed for power supply systems with three-phase five-wire connections, operating at 50 (60) Hz AC, with a rated working voltage of 400V and 660V, and a rated current of up to 5000A. It is suitable for power plants, substations, industrial and mining enterprises, buildings, hotels, airports, docks, and communication centers such as radio and television, to control power generation, transmission, distribution, conversion, and consumption. It also provides reactive power compensation for the main bus through a capacitor compensation cabinet. This equipment complies with national standards: GB7251.1 'Low Voltage Switchgear' and IEC60439 'Low Voltage Switchgear and Control Equipment'.

Use environmental conditions

◆ The ambient air temperature is not higher than +40℃, not lower than-5℃, and the average temperature within 24h is not higher than +35℃.

◆ The relative humidity of the surrounding air should not exceed 50% at the highest temperature of +40°℃, and the relative humidity is higher at lower temperatures, such as 90% at +20℃, but consider that moderate condensation may occur occasionally due to changes in temperature.

◆ Indoor use, the altitude of the place of use shall not exceed 2000m.

◆ It should be installed in a place without violent vibration and impact, and where electrical components are not corroded.

 Main

◆ Cabinet introduction

◇ Basic size of cabinet, receiving cabinet and contact cabinet

Power center (PC) cabinet 

Circuit component selection

The main components in the device are selected from electrical components with advanced technical performance indicators or those that can be mass-produced in China by introducing imported technology.

A, the main circuit breaker 630A and above power supply inlet and feeder circuits, the main selection of DW45 series, NA1 series, AE. series, CW or RMW series, can also choose imported MT series, E series or IZM series, etc.

B. CDM1 series, CM1 series, TM30 series, NM1 series, RMM1 series are mainly selected for feeders below 630A and circuit breakers for motor control. Imported NS series, S series, NZM series plastic shell circuit breakers can also be selected.

C. AC contactors are mainly selected from CDC7, LC1 series, 3TB series, CJX2 series contactors, as well as the accompanying thermal relays and interlocking mechanisms.

D. Current transformers are selected from BH series, SDH series, LMK series, etc.

E, the fuse is selected from RT series or NB series with high breaking capacity.

Table 1