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1. Introduction
The type 3171 is a low-cost, vibration-sensitive, safety switch for the protection of rotating and
reciprocating machinery. 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
• In type 3171MR, the ball and lever are latched by pressing the reset button manually
• In type 3171S, the ball and lever are latched by actuating a solenoid remotely, using an
electrical signal or 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.
Weatherproof Vibration Switch
Types 3171MR and 3171S
Installation and Operating
Manual
EN
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Summary of Contents for Ffeuk 3171MR
- Page 1 • In type 3171MR, the ball and lever are latched by pressing the reset button manually • In type 3171S, the ball and lever are latched by actuating a solenoid remotely, using an electrical signal or by pressing the reset button manually •...
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Page 2: Warnings And Cautions
2. Warnings and Cautions Read all Warnings and Cautions before Installation and Set-up. 2.1 Warnings WARNING ! • Risk of electric shock • For electrical safety, the vibration switch must be earthed • For your own safety, disconnect all electrical power to the vibrating machine and ensure the vibrating machine cannot operate during installation. -
Page 3: Electrical Installation
3.2 Mechanical Installation Details The vibration switch must be fitted on the machine structure so that good transmission is ensured from the likely source of excess vibration. The vibration switch shall be firmly fixed in the vertical orientation shown in figure 1 to a vertical surface of the vibrating machine using M5 fixings suitably resistant to vibration. - Page 4 4.2 Electrical Installation - Details 3mm hex • To avoid breaking the lid hinge, DO NOT push on the lid when fully open. Figure 2: Before Installation Tie-wrap wires to protect against vibration and using cable ties rated for expected ambient temperature.
- Page 5 Switches are shown in their reset state. Figure 4: Wiring Configuration Check lever moves freely up and down. 3mm hex 1Nm max. Figure 5...
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Page 6: Set-Up Sequence
5. Set-up Sequence No adjustment is needed if the vibration switch has been ordered preset for your application. Otherwise, the vibration switch is factory set accurately to 3g. For set up in the field, adjust SET LEVEL so that the switch no longer trips in normal running with reasonable sensitivity to excesssive vibration as follows: Remove SET LEVEL CAP. - Page 7 The SET LEVEL can be estimated by referring to the calibration curve in figure 6 and counting the number of turns from the factory setting. Figure 6: Vibration Switch Calibration Curve. If the factory setting is lost, it can be approximated as 11.5 turns from flush. FLUSH...
- Page 8 6. Functional Test To check correct set-up of the vibration switch, repeat set-up sequence section 5. 7. Maintenance There are no user serviceable parts inside the vibration switch. Maintenance is not required except for periodic external visual inspection of the following: •...