Red Lion Magnetic Pickups & In‐Line Preamplifier Owners Manual

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OUTPUT

VOLTAGE

+

-

(A)

SMALL

GEAR

(B)

OPTIMUM

GEAR

(C)

LARGE

GEAR

(D)

SHAFT

KEYWAY

(E)
BOLT
HEAD

(F)

CAM

MAG.

PICKUP

POLE

DIA.=d

d

3d

d

LEADING

EDGE

TRAILING

EDGE

TRAILING

EDGE

LEADING

EDGE

75

50

25

0

0 5 10 15 20

FIG. 1 OUTPUT WAVEFORMS WITH VARIOUS TARGET SHAPES & SIZES FIG. 2 TYPICAL OUTPUT/AIR-GAP

MagneticPickups&In‐LinePreamplifier

Simple,Reliable&EconomicalSpeedSensorsfor:

Bulletin No. MP-N

Drawing No. LP0020

Released 2016-06-27

SPEEDSWITCHES

DIGITALTACHOMETERS

FREQUENCYTODCCONVERTERS

FEATURES INCLUDE

• NO EXT. POWER NEEDED

• WIDE OPERATING TEMPERATURE RANGE

• EPOXY ENCAPSULATED, MECHANICALLY RUGGED

• IMPERVIOUS TO DIRT, OIL & WATER

• NO MAINTENANCE REQUIRED

• LOW COST

• M12 CONNECTOR (MODEL SPECIFIC)

DESCRIPTIONOFOPERATION

A Magnetic Pickup consists of a permanent magnet, a pole-piece, and
a sensing coil encapsulated in a cylindrical case. An object (target) of
iron, steel, or other magnetic material, passing closely by the pole-piece
causes distortion of the magnetic flux field, which in turn generates a
signal voltage. The magnitude of the signal voltage depends on the
relative size and magnetism of the target, its speed of approach, and
how close it passes the pole-piece.

Magnetic Pickups are most frequently used to sense passing teeth on
a gear, sprocket, or timing belt wheel. They can also be used to sense
bolt-heads, key-ways, or other fast moving metallic targets. Typical
targets and resulting signal wave forms are shown below in Fig. 1.

SELECTINGAMAGNETICPICKUP

Selecting a magnetic pickup is a matter of matching a pickup to a gear
(or other target), to provide enough input signal to a tachometer, speed­switch, or other device for operation at the required minimum speed. The
open-circuit output from a magnetic pickup is directly proportional to
speed, and once the minimum operating speed conditions have been
met, increased signal will occur at higher speeds.

The “1-Volt Threshold Speed” column in the Application and Ordering
Table (next pg.) provides a convenient guide for estimating minimum
operating speeds. This value is the linear surface-speed of a reference
gear required to generate a 1-Volt peak, open-circuit output at an air-gap
of 0.005". The reference gear listed for each pickup is near the optimum
size for that pickup, as defined by the criteria in Fig. 1B. The RPM listed
is for a reference gear with 60 teeth running at that surface-speed. Gears
with larger teeth provide about the same or somewhat more output at the
same surface-speed, while gears with smaller teeth or fewer number of
teeth yield lower outputs. Figures 1C - 1F need a very high surface
speed to generate a 1-Volt peak. The “Minimum Gear Size” column lists
the Diametral Pitch size at which the output drops to 40-60% of the
output when the reference gear is used. Gears with very small teeth in
relation to the pole-piece diameter, deliver greatly reduced outputs, as

shown in Fig. 1A. Threshold outputs when using targets other than gear
teeth can be estimated by their relative size with respect to the reference
gear teeth. For more information on gears, definitions and relationships,
see the Sensing Gears Bulletin (LP0167).

The 1-Volt Threshold Speeds are based on a 0.005" air-gap. In
applications where this air-gap cannot be maintained or where the air-gap
can vary due to eccentricity of the sensing gear, a correction factor can be
applied from the curve in Fig 2. The effect of electrical loading is usually
minimal at low speeds and low output frequencies, however, output
voltage drop due to loading at high frequency or with low impedance
inputs can be estimated based on the Output Impedance data.

Magnetic Pickups are recommended for speed related sensing
applications. They are not recommended for counting applications, since
loss of counts will occur at low speeds. For devices not designed to
accept a magnetic pickup input, the Red Lion Controls model ASTC can
be used to convert the magnetic pickup output into an NPN open
collector output. The ASTC can detect magnetic pickup outputs as low
as 20 mV, which allows for operating speeds below the specified 1-Volt
threshold speed.

100

REL. OUTPUT %

-1-

AIR GAP (INCHES x .001)

25

Released 2016-06-27 Bulletin No. MP-N

MP25TA

0.040" (1.016)

DIA. POLE TIP

(17.45 ±0.254)

(7.95)

0.02" (0.51)

6.0"

0.313"

0.687 ±0.01"

REF.

(152.4)

MIN.

28 AWG.

VINYL LEADS

0.094" (2.387)

DIA. POLE TIP

0.812 ±0.01" 0.439"

0.02" (0.51)
3/8"-24 UNF-2A THREAD

6.0"

MP37TA

(152.4)

(11.15)

(20.62 ±0.25)

REF.

MIN.

28 AWG.

VINYL LEADS

0.094" (2.387) DIA.
POLE TIP

(20.62 ±0.25)

MP37TAC1

PIN 1

PIN 2

PIN 3

PIN 4

0.02" (0.51)

1.60 ±0.025" (40.64 ±0.635)

3/8"-24 UNF-2A THREAD

0.812 ±0.01"

45°

See Note 7
for pin-out
information

0.094 ±0.005"

DIA. POLE TIP

8.0"

(203.2 )

+2.0"

-0.0"
+50.8

-0.0

0.373"

(9.474 )

+0.000"

-0.005"

+0.000

-0.127

(2.39 ±0.13)

2.50 ±0.03" (63.5 ±0.76)

MP37CA

FLUSH WITH CASE

20 AWG.

VINYL LEADS

0.02 (0.50)

DIA. POLE TIP

2.125 ±0.01"

MP62TA

(53.98 ±0.25)

(3048)

MIN.

(15.88)

(2.92 ±0.38)

0.115 ±0.015

24 AWG.
VINYL JACKETED
SHIELDED CABLE

0.625" (15.88) REF.

PIN 4

PIN 3

PIN 1

PIN 2

(50.8 ±0.254)

0.02 (0.50)

0.115 ±0.015
(2.92 ±0.38)

MP62TAC1

DIA. POLE TIP

2.00 ±0.01"

45°

See Note 7
for pin-out
information

2.125 ±0.01"

(15.88)

MP62TB00

(3048)

BLIND END SHELL

0.106 (2.69) DIA.

EFFECTIVE POLE TIP

10' 0"

MIN.

(53.98 ±0.25)

0.625"

24 AWG.
VINYL JACKETED
SHIELDED CABLE

BLIND END SHELL

0.187" (4.75)

DIA. POLE PIECE

(47.63)

(31.75)

LEAD LENGTH MIN.

18 AWG.

FLEXIBLE LEADS

0.5" INTERNAL PIPE THREAD

N.C.

N.C.

PIN 2

PIN 1

PIN 3

+

PIN 4

-

45°



Drawing No. LP0020

MAGNETICPICKUPAPPLICATION&ORDERINGINFORMATION

MODEL NO. DIMENSIONS

MP-25TA

1/4"-40 UNS-2A THREAD

MP-37TA

1-VOLT

THRESHOLD

SPEED (1)

135 in/sec

1000 RPM

60T 24 D.P.

Ref. Gear

33 in/sec
200 RPM

60T 20 D.P.

Ref. Gear

MINIMUM

GEAR

PITCH (2)

TEMP.

RANGE

°C

48 D.P. -40 to +107

32 D.P. -40 to +107

OUTPUT

IMPENDANCE

130 Ω ±20%

15 mH

340 Ω ±20%

44 mH

PART NUMBER

MP25TA00

MP37TA00

MP-37TAC1

MP-37CA

10' 0"

0.625"

MP-62TA

5/8" - 18 UNF-2A THREAD

MP-62TAC1

5/8-18UNF-2A THREAD

MP-62TB

5/8" - 18 UNF-2A THREAD

MP-75TX

1.875"

1.25"

36.0"

(914.4)

Explosion

Proof (3)

3/4" 20 UNEF-2A THREAD

NOTES:

1. Surface speed, of listed reference gear, is @ 0.005" air-gap.

2. Gear pitch where output will drop to 40-60% of that generated by the
reference gear size, at the same surface speed.

3. UL Listed CSA Certified, Class I Group A, B, C and D; Class II Group
E, F and G. (AI-TEK Instruments) PN#AIRPAX/70085-1010-005, UL
File #E40545 (N), CSA File #042648.

4. Polarity, all pickups: white output lead goes positive with respect to
black when target approaches pole.

5. 2-Wire shielded cable is recommended for all magnetic pickup outputs.
Connect the shield to the “COMMON” or “GROUND” terminal of the
instrument being used. DO NOT run Magnetic Pickup signal leads in
conduit, troughs, or bundles with other power or control voltage lines.

33 in/sec
200 RPM

60T 20 D.P.

32 D.P. -40 to +107

340 Ω ±20%

44 mH

MP37TAC1

Ref. Gear

30 in/sec
180 RPM

60T 20 D.P.

32 D.P. -40 to +107

300 Ω ±30%

65 mH

MP37CA00

Ref. Gear

10 in/sec

50 RPM

60T 16 D.P.

24 D.P. -40 to +107

1200 Ω ±20%

400 mH

MP62TA00

Ref. Gear

10 in/sec

50 RPM

60T 16 D.P.

24 D.P. -40 to +107

1200 Ω ±20%

400 mH

MP62TAC1

Ref. Gear

20 in/sec
100 RPM

60T 16 D.P.

24 D.P. -40 to +107

1200 Ω ±20%

400 mH

MP62TB00

Ref. Gear

30 in/sec
100 RPM

60T 10 D.P.

12 D.P. -73 to +93

230 Ω ±20%

100 mH

MP75TX00

Ref. Gear

6. Lead length of magnetic pickup should not be extended. An ASTC0000
can be used to convert the magnetic pickup signal to NPN Open
Collector style output, which allows for a much greater transmission
distance.

7. M12 unit color codes for CCM12S01 cable used with MP37TAC1 and
MP62TAC1 is:

PIN 3 - Blue (-)
PIN 4 - Black (+)
PIN 2 - NC
PIN 1 - NC

ACCESSORIES

MODEL NO. DESCRIPTION PART NUMBER

ASTC In-Line Amplifier ASTC0000

CCM Mating Cable With M12 Connector, 1 Meter In Length CCM12S01

Do not dispose of unit in trash - Recycle

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