FFE 3171 Ex User Manual

Explosionproof Vibration Switch
Type 3171 Ex
Installation and Operating
Manual
EN
1. Introduction
The type 3171 Ex is a low-cost, vibration-sensitive, safety switch for the protection of rotating
and reciprocating machinery in hazardous environments. It is adjusted to operate above the
machine's normal running levels of vibration, activating machine shut-down circuits and/or
alarms and to switch off the machine before catastrophic failure.
The switch detects vibration in all directions. Unbalanced forces created by failing machinery
contain both the fundamental frequency and harmonics. The switch responds by shutting off the
machine if any components of vibration exceed the set value.
The switch operates as follows:
• Mounted vertically on a vibrating machine, a steel ball is held by a permanent magnet into
a conical seat
• If the vibration of the machine is sufficient to cause the ball to detach from the magnetic
field of the magnet, it trips a latched lever, thus releasing a micro switch plunger so the
machine can be stopped
• The ball and lever are latched by pressing the reset button manually
• The SET LEVEL of the vibration switch is set by adjusting the gap between permanent
magnet and ball.
Consult the FFE website at www.ffeuk.com for the latest information on applications and any
new warnings that may affect installation or safety.
1

FFE 3171 Ex Specifications

General

Brand	FFE
Model	3171 Ex
Category	Switch
Language	English

Summary

Introduction

Warnings and Cautions

Warnings

Critical safety warnings for installation and operation.

Cautions

Cautions regarding corrosion, cable entry, and Ex protection.

EMC Requirements

Advises on using specific cables/conduits for EMC compliance.

Terminal Block Specifications

Details terminal block type, certification, and ratings.

Product Label Information

Describes information on the product label, including certifications.

Mechanical Installation

Mechanical Installation Introduction

Introduces mechanical installation, handling, and environmental limits.

Mechanical Installation Details

Details fitting the switch vertically with M5 fixings on a vibrating machine.

Electrical Installation

Electrical Installation Introduction

Covers switch contact ratings, wiring, and temperature considerations.

Electrical Installation Details

Provides illustrated steps for electrical installation, wiring specs, and torque values.

Set-up Sequence

Functional Test

Maintenance

Accessories