FW MURPHY MP3298 Magnetic Pickups Installation Guide

FW MURPHY MP3298 Magnetic Pickups

A magnetic pickup is an AC generator. It is normally installed into the flywheel housing of an internal combustion engine. The starter ring gear acts upon it to generate a voltage pulse each time a gear tooth passes the end of the sensor.

Product Overview

Specifications

Housing Material:
MP3298: Type 300 Stainless Steel; Locknut: Type 300 Stainless Steel
MP7905 and MP7906: Type 6061 Aluminum/Anodize Class 1 Locknut: steel nickel plated
Output Leads (all models): Two insulated leads, 20 AWG, STR/
TEF insulated per MIL-W-16878D Type E, 1 White and 1 Black
Output Voltage (all models): 200 V.P.P. TYP. (tested at 1000 I.P.S. 20 Pitch gear, 0.005 Gap., and 100K OHM Load) Coil Resistance:
MP3298: 975 Ohms TYP
MP7905 and MP7906: 2500 Ohms TYP
Potting (all models): Internal portion of pickup is filled with epoxy resin, making the magnetic pickup oil- and moisture-resistant. Temperature (all models): -65° to +225° F (-54° to 107° C) Coil Induct.:
MP3298: 800 mH max, @ 1 KHz
MP3298: 400 mH TYP. @ 1 KHz

Magnetic Pickup Installation

Flywheel Housing
Drill and tap a hole in the flywheel housing (See below for model and thread size).
IMPORTANT: Drilling too deep may damage ring gear teeth.
Blow chips with air hose when drilling and tapping hole.

Drill and Tap Chart

Set Gap Adjustment

Insert magnetic pickup and turn until it stops at the face of the gear. Back off the gear by turning the pickup counter clockwise 1/4, 1/2 or 3/4 turn. See Gap Chart to determine gap distance based on the turn. Check gap clearance by rotating the gear completely around.

NOTE: Magnetic pickup gap should be adjusted so that the minimum voltage required is attained at the engine’s lowest RPM. The voltage will increase as the speed increases. If erratic readings occur, remove the magnetic pickup and check the magnetic tip for metal chips.

Gap Chart

TURN

|

1/4

| .013 in.
(0.33 mm)| .015 in•

(0.38 mm)

1/2

| .028 in.
(0.71mm)| .030 in•

(0.76 mm)

3/4

| . 035 in.
(0.88 mm)| .045 in•

(1.14 mm)

1| .055 in.
1.39 mm)| .062 in•

(1.57 mm)

| GAP

In order to consistently bring you the highest quality, full-featured products, we reserve the right to change our specifications and designs at any time. FW MURPHY product names and the FW MURPHY logo are proprietary trademarks. This document, including textual matter and illustrations, is copyright protected with all rights reserved. (c) 2022 FW MURPHY. A copy of our typical warranty may be viewed or printed by going to www.fwmurphy.com/warranty.

Dimensions

A. MP3298 and MP7906 = 3 in. (76 mm) MP7905 = 4.5 in . (114 mm)
B. MP3298 = 5/8-18 UNF-2A MP7905 and MP7906 = 3/4-16 UNF-2A
C. MP3298 = 0.250 in. (6 mm) MP7905 and MP7906 = 0.370 in. (9 mm)
Polarity: White lead is positive with respectto Black lead upon approach of ferrous metal.

Gear Pitch/Voltage Output

Note: Dash indicates not recommended.

Output Voltage Operating Chart

Note: Tested at 1000 I.P.S. 20 pitch gear, 0.005 gap and 100K OHM load.

Customer Support

FW MURPHY PRODUCTION CONTROLS
SALES, SERVICES & ACCOUNTING
4646 S. HARVARD AVE.
TULSA, OK 74135
MANUFACTURING
2151 RANDON DYER ROAD
ROSENBERG, TX 77471
5757 FARINON DRIVE
SAN ANTONIO, TX 78249

DOMESTIC SALES & SUPPORT
FW MURPHY PRODUCTS
PHONE: 918 9571000
EMAIL: INFO@FWMURPHY.COM
WWW.FWMURPHY.COM
FW MURPHY CONTROL SYSTEMS & SERVICES
PHONE: 281 633 4500
EMAIL: CSS-SOLUTIONS@FWMURPHY.COM

INTERNATIONAL SALES & SUPPORT
CHINA
PHONE: +86 571 8788: 6060
EMAIL: INTERNATIONAL@FWMURPHY.COM
LATIN AMERICA & CARIBBEAN
PHONE: + 1918 770 8775
EMAIL: INTERNATIONAL@FWMURPHY.COM
SOUTH KOREA
PHONE: +82 70 7951 4100
EMAIL: INTERNATIONAL@FWMURPHY.COM

References

• Warranty & Terms of Sale - FW Murphy Production ControlsFW Murphy Production Controls

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