Siemens SENTRON 3VL250 User Manual

System Manual
SENTRON
Protection devices
3VL IEC molded case circuit breakers
11/2013Edition
Answers for Infrastructure & Cities.

Siemens SENTRON 3VL250 Specifications

General

Brand	Siemens
Model	SENTRON 3VL250
Category	Protection Device
Language	English

Summary

Product description

Overview 3VL

General description and types of 3VL molded case circuit breakers, including their climate-proof design.

SENTRON VL types

Application overview

System protection

Describes releases designed for protecting cables and non-motorized loads against overload and short-circuit.

Motor protection

Details application for optimal protection and direct starting of three-phase AC squirrel-cage motors.

Starter combination

Configuration

Functional principle

Explains the trip-free mechanism, contact operation, and current limiting principles of the circuit breakers.

Electronic overcurrent trip unit (ETU)

Describes the functionality of ETUs, using electronics and current transformers to capture and compare currents.

Functions

Protection functions

Overview of the protective functions offered by the 3VL molded case circuit breakers.

Overcurrent release

Description of the overcurrent release mechanism, including main connections and internal view.

Differential current protection with RCD module

Describes protection against ground faults using RCD modules, ensuring protection against alternating and pulsating currents.

Ground-fault protection

Explains protection against fault currents flowing to ground that can cause fires in the plant.

Application planning

Use with frequency converters

Use of capacitor banks

Transformer protection on the primary side

Application of circuit breakers for protecting transformers, considering high inrush current peaks.

Use in DC systems

Guidelines and selection criteria for using 3VL molded case circuit breakers in DC systems.

Use in motor protection

Details on using circuit breakers for optimal protection and direct starting of three-phase AC squirrel-cage motors.

Installing/mounting

Installation methods

Overview of installation methods: fixed-mounted, plug-in, and withdrawable versions.

Mounting and safety clearances

Guidelines for permissible mounting positions and required safety clearances.

Locking devices

Connecting

Cables and busbars

Main connection types for fixed mounting

Main connection methods for plug-in and withdrawable version

Displays and operator controls

Overcurrent trip unit without LCD display

Overcurrent trip unit with LCD display

Parameter assignment / addressing

Setting the parameters

Guide to setting protection parameters on the electronic trip unit (ETU) based on system requirements.

Setting the protection parameters for motor protection (ETU10M, ETU30M and LCD-ETU 40M)

Specific parameter settings for motor protection applications, covering overload and short-circuit protection.

Service and maintenance

Preventive measures

Guidelines for qualified personnel regarding functionality tests and maintenance inspection intervals.

Troubleshooting

Common fault causes and corrective actions for circuit breaker issues like tripping or functional errors.

Technical data

General data - 3VL molded case circuit breakers

Key electrical specifications, rated voltages, and permissible ambient temperatures for 3VL breakers.

Technical overview

Configuration of main connections

Motor Protection

Motorized operating mechanisms

RCD modules

Undervoltage release

Shunt release

Ground-fault detection

Circuit diagrams

Circuit diagrams VL1 ... 8 motorized operating mechanism (MO)

Control with undervoltage release

Circuit diagrams VL1 ... 6, motorized operating mechanism with stored energy mechanism, with or without undervoltage release

Circuit diagrams, undervoltage release and shunt release

Circuit diagrams 3VL plus RCD module