Technical Information · issue 10 of 2006
New tachometers EDT 7 and EDT 8; New ignition systems; Tachometer EDT 7; Tachometer EDT 8; Antennas supplied with the units; Method; Battery life; Pictograms in the supplement for the EDT 8; Hour meter; Summary
IssueTI 10/2006
Full text
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STIH)
Technical Information 10.2006
New STIHL special tools
Contents
1. New tachometers EDT 7 and EDT 8
1.1 New ignition systems
1.2 Tachometer EDT 7
1.3 Tachometer EDT 8
1.4 Antennas supplied with the units
1.5 Method
1.6 Battery life
1.7 Pictograms in the supplement for the EDT 8
1.8 Hour meter
1.9 Summary
1. New tachometers EDT 7 and
EDT 8
1.1 New ignition systems
The development of new ignition systems has made
it necessary to use new tachometers.
The principle of operation underlying the new
ignition systems is different from that of the
"standard" ignition system.
Both pairs of poles are used to generate electrical
pulses. One pair of poles is used to generate the
energy for ignition. The other pair is used to
generate pulsating electrical power which can be
used for various purposes, depending on the design
of the ignition system.
The new ignition systems used on some models can
be identified by their flywheels with two pairs of
magnetic poles.
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)m~ge 2 Technical Information 10.2006
The second pair of poles generates a relatively high Features of the EDT 7:
impulse voltage which is registered by the
- Used for engines with one cylinder
tachometer and used for indication of the speed,
depending on the instrument's electrical design. - Used with two-stroke and four-stroke engines
This means that, for every revolution of the flywheel, with one ignition pulse for each revolution of the
the tachometer can indicate two revolutions of the crankshaft. Can be adjusted for one pulse per
power unit, which effectively constitutes a two revolutions.
measuring error. - Storage and indication of the maximum speed
The new tachometers are designed and built in such - Operation and adjustment of settings via a
a way that they only process and indicate the single button
ignition pulses of the new ignition systems.
Operation of the EDT 7 is described in a manual
The purposes for which the second electrical pulse supplied with the unit.
is used are described in the Technical Information
bulletins issued when a power tool with newly The previous tachometer EDT 5 can continue to be
developed ignition system is launched on the used for "standard" STIHL ignition systems.
market.
1.3 Tachometer EDT 8
1.2 Tachometer EDT 7
901TI050 KN
Left: Previous version DET-303 –
Part No. 0464 801 0000
Right: New version EDT 8 –
Part No. 5910 850 1009
The new tachometer EDT 8 supersedes the
901TI041 KN
previous version DET-303.
Features of the EDT 8:
Left: Previous version EDT 5 –
- Used for engines with one cylinder
Part No. 5910 850 1006
Right: New version EDT 7 – - Used with two-stroke and four-stroke engines
Part No. 5910 850 1008 with one ignition pulse for each revolution of the
crankshaft
The new tachometer EDT 7 supersedes the
- The setting cannot be changed
previous version EDT 5. Both versions are
characterized by the fact that they can be adjusted Operation of the EDT 8 is described in a supplement
to the operating principle and ignition system of the enclosed with the unit (see also 1.7).
engine concerned by changing the setting. The previous tachometer DET-303 can continue to
be used for "standard" STIHL ignition systems.
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Technical Information 10.2006 Page 3
1.4 Antennas supplied with the units 1.5 Method
1.5.1 Measurement with test line
901TI043 KN
The two new tachometers are supplied complete
with two antennas of different lengths:
- Test line (A) with a length of approx. 24 in
(60 cm) and a terminal which is clamped directly
onto the insulation of the ignition lead or spark
plug boot.
901TI045 KN
- Short antenna (B) with a length of approx. 6 in
(15 cm) for measurement without contact.
Pulses should be measured with the test line. This
method yields the most accurate results.
. Clamp the test line onto any point on the
2. insulation of the ignition lead or spark plug boot.
1.
1.5.2 Measurement with short antenna
901TI044 KN
Both the test line and the antenna can be attached
to the housing in the same simple way, as illustrated
above.
A
901TI046 KN
This method is useful for measuring the speed of
engines in which it is difficult or impossible to clamp
the test line onto the ignition lead or spark plug boot.
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)m~ge 4 Technical Information 10.2006
During measurement: 1.6 Battery life
. Ensure that distance (A) remains between The battery in the two new tachometers cannot be
4 and 8 in (10 and 20 cm). replaced. The battery has a service life of
approximately ten years in normal use.
. Direct the antenna towards the pulse-
conducting parts of the ignition system.
Steady indication of the speed on the display means
1.7 Pictograms in the supplement for the
that the tachometer is properly aligned.
EDT 8
Operation, the essential technical data and the
unit's use are explained by means of drawings and
1.5.3 Measurement with built-in antenna pictograms in the supplement enclosed with the
EDT 8.
B 1.7.1 Explanation of pictograms
Use
A B C
901TI047 KN
This method is useful if a test line cannot be used
and when the measurement must be made close to
the engine or to the pulse-conducting parts of the
ignition system.
During measurement:
. Keep distance (B) as short as possible
(max. 2 to 4 in (5 to 10 cm)).
. Direct the built-in antenna and the arrow on the
unit towards the pulse-conducting parts of the
901TI048 KN
ignition system.
Steady indication of the speed on the display means
that the tachometer is properly aligned.
Preference should be given to the measurement A Two-stroke engine with one cylinder and one
methods outlined in 1.5.1 and 1.5.2. ignition pulse for each revolution of the
crankshaft.
B STIHL 4-MIX® engine with one cylinder and
one ignition pulse for each revolution of the
crankshaft. Four-stroke engine with lubrication
by the fuel mixture.
C Four-stroke engine with one cylinder and one
ignition pulse for each revolution of the
crankshaft. Engine with separate lubrication.
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Technical Information 10.2006 Page 5
Technical data
901TI049 KN
– 40 °C to +70 °C Operating temperature
– 40 °F to +158 °F range
0–16 000 1/min Maximum range for
0–16,000 rpm indication of the speed
Disposal
Electrical devices must not be disposed
of as household waste. The device,
accessories and packaging should be
recycled in an environment-friendly
manner.
1.8 Hour meter
The new EDT 7 and EDT 8 tachometers do not have
an hour meter function
1.9 Summary
Item Part name Previous New Remarks
1 Tachometer EDT 5 5910 850 1006 --- 1)
2 Tachometer DET-303 0464 801 0000 --- 1)
3 Tachometer EDT 7 --- 5910 850 1008
4 Tachometer EDT 8 --- 5910 850 1009
Remarks
1) Previous version of part only remains available while stocks last.
Last Technical lnformation on STIHL special tools: 23.2005
© ANDREAS STIHL AG & Co. KG, 2006 Technical Documentation
D1/MTK-na
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