Operation Manual / Power2 850-M / 4 Product description
4 Monitoring during operation / 4.3 Speed measurement
© Copyright 2020 ABB. All rights reserved.
HZTL4061_EN
Rev.D
March 2020
4.3.3
Differences in speed between the low-pressure or high-
pressure stages on one engine
The speeds of the low-pressure stages differ significantly from the speeds of the high-pres-
sure stages.
A Power2 turbocharging system for V-engines, for example, can consist of multiple low-pres-
sure and multiple high-pressure stages. In this case the speeds of the low-pressure stages
only differ a little from each other. The same also applies to the high-pressure stages.
The difference between the highest and the lowest speed must not be more than 3 %, relat-
ive to the speed limit n
Bmax
.
If this admissible difference range is exceeded, the following steps must be performed:
u
Reduce the engine performance until the maximum speed of all low and high pressure
stages does not exceed 70% of n
Bmax
.
u
If the engine cannot be stopped, it can continue to be driven with this reduced engine
performance or at this low-pressure and high-pressure stage speed.
u
If a low-pressure or high-pressure stage surges continuously, the engine performance
must be reduced further.
u
Measure the temperatures in the air lines and exhaust gas pipes from and to the low-
pressure and high-pressure stages and compare with normal values.
u
Check the pressure loss of the alternative air inlet and compare it with normal values.
If the engine can be stopped temporarily:
u
Inspect air lines, exhaust gas pipes and the low-pressure and high-pressure stages and
remedy any malfunctions.
u
In any case, contacting the nearest ABB Turbocharging Service Station is recommended.
4.3.4
Malfunction of the speed measurement system
The possible reasons for malfunction of the speed measuring system are described in
chapter Troubleshooting /
.
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21
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