Operation Manual / TPL76-C
4 Operation / 4.4 Speed measurement
© Copyright 2017 . All rights reserved.
HZTL2485_EN
Revision E
July 2017
4.4.1
Speed differences with multiple turbochargers per
engine
The speeds of all turbochargers on one engine differ only slightly from
each other in normal operation.
The difference between the highest and the lowest turbocharger speed
must not be more than 3 % relative to the speed limit n
Bmax
.
If this permissible range of difference is exceeded, the following steps
must be carried out:
u
Reduce engine performance immediately until the highest turbochar-
ger speed no longer exceeds 70% of n
Bmax
.
u
If the engine cannot be stopped, continue to run at this reduced en-
gine performance or turbocharger speed.
u
If the turbocharger surges continuously, engine performance must be
reduced further.
u
Measure the temperatures in the air and gas lines to and from the tur-
bochargers and compare them with standard values.
If the engine can be stopped for a short time:
u
Inspect the air and gas lines as well as the turbocharger and eliminate
any problems.
u
In any event, it is recommended that you contact the nearest ABB Tur-
bocharging Service Station.
4.4.2
Assembly
If the speed sensor is not fitted on the turbocharger, the following pro-
cedure must be adopted to fit it:
w
Engine and turbocharger are not running.
w
The turbocharger lubricating system is switched off.
u
Remove screw plug (42047) from bearing casing.
NOTICE
Part position
The position of the screw plug for measuring the speed is marked "
n
"
on the bearing casing.
u
Screw in speed sensor (86505) as far as it will go and tighten to
torque specified in table. (See chapter Table of tightening torques.)
u
Connect speed sensor using cable connector (86515).
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