TM Page 30
Figure 7 - Installation of Transmitter and Split-Ring "TX.MTGS" and Inductive Head IH2
INDUCTIVE
HEAD
IH2.
ALIGN
PARALLEL
TO
LOOP
AS
SHOWN.
AIRGAP 10-20MM
CABLING
FROM STRAIN-
GAUGE
BRIDGE
0.7MM
DIAMETER
COPPER WIRE LOOP.
DON’T OVERHEAT TABS
WHEN SOLDERING
GROUND
CABLE
SCREEN
&
TRANSMITTER P8
TO HOUSING
TRANSMITTER
SCREENING
COVER
TRANSMITTER
ATTACHED
TO SHAFT WITH TX.MTGS
SPLIT-RING
ASSEMBLY.
NOTE:
COUNTER-BALANCE
MODULE (NOT SHOWN) WILL
NORMALLY FITTED AT 180
°
TO TRANSMITTER
The following sections describe installation of each possible inductive power supply components combination:-head/loop,
loop/loop and loop/IP2 module). Installation procedure is the same for both single channel and multi-channel "D" range
PCM and also "B" range fm/fm systems.
MOST DIFFICULTIES WITH ROTARY TELEMETRY INSTALLATIONS OCCUR AS A RESULT OF DROPOUTS IN THE
INDUCTIVE POWER SUPPLY TO THE TRANSMITTER. PLEASE READ THE APPROPRIATE SECTION CAREFULLY!
5.1
INDUCTIVE HEAD IH2 OR IH2/L WITH SHAFT MOUNTED POWER PICKUP LOOP
The IH2 and long pole piece version IH2/L (for larger diameter shafts) consists of a coil wound around a "U" shaped ferrite
core and encapsulated within a housing. The head is located in a position close to a loop antenna wound around the shaft.
An internal capacitor tunes the head inductance to resonance, necessary for efficient operation. In operation the IH2 coil is
energised by a power oscillator in the demodulator/decoder module, usually at 2MHz. This generates an alternating
magnetic field across the pole pieces, which induces power into the loop. The IH2 or IH2/L may be used with the special
manufacture split-ring assembly (general part number "TX.MTGS"), which will have either a locating groove for the loop
wire, an integrated glass-fibre ring with printed copper track, or a single/two turn loop wound onto the shaft itself (with an
intervening insulating layer of 10-15mm).
A fine tuning adjustment is incorporated in the IH2, IH2/L housing to enable initial tuning to resonance. If the installation is
close to metal components, which can affect the head tuning, this adjuster may be used to re-tune and improve efficiency.
Once set, the tuning core should be locked in position with a small amount of silicone rubber to prevent movement and a
possible loss of tuning (which would then cause a voltage drop in the DC supply to the transmitter).
5.1.1
Inductive Head IH2 or IH2/L with Power Pickup Loop in Split-Ring Assembly "TX.MTGS"
A system option for high RPM applications is the custom design split-ring assembly "TX.MTGS". This fits around the shaft
O.D. and incorporates a power pickup/signal transmit loop antenna and also mounting for the transmitter, either in a cut-out
section or contained within the ring. The TX.MTGS ring is manufactured from phenolic composite or aluminium, dependant
upon the application.
See figure 7 below and "Suggested Installation Sequence" text.
Содержание TX31D/1/IFM
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