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Catalog Subsection for Table of Contents
Magnetic Pickups
Models MP3298, MP7905 and MP7906 sect. 70
1511775
2016/02/25
(00-02-0181)
Gap Adjustment
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, 20AWG, 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 moist-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
PIckup Model Part Number
MP3298
MP7906
MP7905
20700162
20700161
20700160
Total Length
3 in. (76 mm)
Threaded Length
3 in. (76 mm)
3 in. (76 mm) 3 in. (76 mm)
4-1/2 in. (114 mm) 4-1/2 in. (114 mm)
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 chiips.
Thread Size
5/8-18 UNF
3/4-16 UNF
3/4-16 UNF
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.
Dimensions
with all rights reserved. (c) 2016 Enovation Controls, LLC. A copy of the warranty may be viewed or printed by going to www.fwmurphy.com/warranty.
Magnetic Pickup Installation
Drill and tap a hole in the flywheel housing (See
Specifications for model and thread size). IMPORTANT:
Drilling too deep may damage ring gear teeth. Blow chips with air hose when drilling and tapping hole.
Gear Pitch/Voltage Output
Gear Pitch % Output Std. Volts
16
20
24
32
48
64
72
6
8
10
12
Note: Dash indicates not recommended.
118
100
85
23
-
-
-
187
172
162
157
Output Voltage Operating
Chart
Gap Chart
Note: Tested at 1000 I.P.S. 20 pitch gear, 0.005 gap and 100K OHM load.
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